Abstract:  The aims of the present study were to evaluate the effect of a meal rich in virgin olive oil on triacylglycerol composition of human postprandial triacylglycerol-rich lipoproteins (fraction Sf > 400), and to assess the role of the triacylglycerol molecular species concentration and polarity on lipoprotein clearance. Fasting (0 h) and postprandial blood samples were collected hourly for 7 h from eight healthy normolipidemic subjects after the ingestion of the meal. Plasma and lipoprotein triacylglycerol concentrations increased quickly over fasting values and peaked twice at 2 and 6 h during the 7-h postprandial period. The triacylglycerols in the lipoprotein fraction at 2 h generally reflected the composition of the olive oil, however, the proportions of the individual molecular species were altered by the processes leading to their formation. Among the major triacylglycerols,  the proportion of triolein (OOO; 43.6%) decreased (P < 0.05), palmitoyl-dioleoyl-glycerol (POO; 31. 1%) and stearoyl-dioleoyl-glycerol (SOO; 2.1%) were maintained and linoleoyl-dioleoyl-glycerol (LOO; 11.4%) and palmitoyl-oleoyl-linoleoyl-glycerol (POL; 4.6%) significantly increased (P < 0.05) compared with the composition of the triacylglycerols in the olive oil. Smaller amounts of endogenous triacylglycerol (0.8%), mainly constituted of the saturated myristic (14:0) and palmitic (16:0) fatty acids, were also identified. Analysis of total fatty acids suggested the presence of molecular species composed of long-chain polyunsaturated fatty acids of the (n-3) family, docosapentaenoic acid, [22:5(n-3)] and docosahexaenoic acid (DHA), [22:6(n-3)] and of the (n-6) family [arachidonic acid, [20:4(n-6)]. The fastest conversion of lipoproteins to remnants occurred from 2 to 4 h and was directly related to the concentration of the triacylglycerols in the lipoprotein particle (r = 0.9969, P < 0.05) and not with its polarity (r = 0.1769, P > 0.05). The rates of clearance were significantly different among the major triacylglycerols (OOO, POO, OOL and POL) (P < 0.05) and among the latter ones and PLL (palmitoyl-dilinoleoyl-glycerol, POS (palmitoyl-oleoyl-stearoyl-glycerol) and OLL (oleoyl-dilinoleoyl-glycerol) (P < 0.01). OOO was removed faster and was followed by POO, OOL, POL, PPO (dipalmitoyl-oleoyl-glycerol), SOO, PLL, POS and OLL.
 

Alaiz, M., F. J. Hidalgo and R. Zamora
Effect of pH and temperature on comparative antioxidant activity of nonenzymatically browned proteins produced by reaction with oxidized lipids and carbohydrates.
Journal of Agricultural and Food Chemistry 47 (1999) 748-752.
ISSN: 0021-8561

Abstract: The antioxidative activity of nonenzymatically browned bovine serum albumin (BSA) produced by reaction with ribose (RI), hydroperoxides of methyl linoleate oxidation (HP), and secondary products of methyl linoleate oxidation (SP), at different pHs (4, 7, and 10), and temperatures (25, 37, 50, 80, and 120 ºC), was studied to compare the antioxidative effects of carbohydrate- and oxidized lipids-modified proteins. The modified proteins (RIBSA, HPBSA, and SPBSA) were tested for antioxidative activity (at 100 ppm) in soybean oil using the thiobarbituric acid-reactive substances (TBARS) assay. All of them decreased significantly (p < 0.05) the TBARS formation in the oil and exhibited different effectiveness as a function of the temperature and the pH of the medium. In addition, there was a good correlation between the antioxidative activity of the protein and the amino acid losses produced during the nonenzymatic browning. These results are in agreement with an analogous and complimentary contribution of both Maillard and oxidized lipid/protein reactions to the antioxidative activity produced in foods during processing and storage.
 

Aparicio, R.,  L. Roda, M.A. Albi  and F. Gutierrez
Effect of Various Compounds on Virgin Olive Oil Stability Measured by Rancimat.
Journal Agricultural and  Food Chemistry 47 (1999) 4150-4155.
ISSN: 4376-4381.

Abstract: Phenolic and orthodiphenolic compounds together with carotenoids, tocopherols, pigments, and fatty acids were tested for their antioxidant effect in 79 samples of virgin olive oils cv. Picual and Hojiblanca. A linear regression based on the oleic/linoleic ratio and the contents of phenols and toco-pherols showed a good correlation (adjusted-R2= 0.91) with the stability measured by the percentage contribution of each chemical variable to stability is discussed. The contribution of phenolic and orthodiphenolic compounds was around 51%, the composition of fatty acids 24%, and in less percentage a-tocopherol, carotenoids, and chlorophylls. No effect or very little, was shown by b and g tocopherols.
 

Barrera-Arellano, D., M.V. Ruiz-Méndez,  G. Márquez-Ruiz and M.C. Dobarganes
Loss of  tocopherols and formation of degradation compounds in triacylglycerol model systems heated at high temperature.
Journal of the Science of  Food and Agriculture 79 (1999) 1923-1928.
ISSN: 0022-5142

Abstract: Triolein, trilinolein and mixture of both (1:1) were heated at 180ºC for 2, 4, 6, 8 and 10 hours in the absence of tocopherols or in the presence of  a-tocopherol (500 mg/Kg);  d-tocopherol (500 mg/Kg); and a mixture of  a-,  b-,  g- and  d-tocopherol (200-250 mg/Kg each). Losses of tocopherols as well as increases in polymeric triacylglycerols were followed. Total polar compounds were also evaluated after 10 hour heating. Results demonstrated that the antipolymerisation effect of tocopherols at high temperature depended on the degree of unsaturated affecting in a greater extent to the less unsaturated substrate, triolein. The maximum effect for the three substrates was found when the tocopherol mixture was added. Interestingly,  a-tocopherol losses were very rapid and independent of the unsaturation of the triacylglycerol system under the conditions used, although degradation of the substrate was significantly higher as the degree of unsaturation increased for any period of heating.
 

Berdeaux, O., G. Márquez-Ruiz and M.C. Dobarganes
Characterization, quantitation and evolution of monoepoxy compounds formed in model systems of fatty acid methyl esters and monoacid triglycerides heated at high temperature.
Grasas y Aceites 50 (1999) 53-59
ISSN: 0017-3495

Abstract: Monoepoxy compounds formed after heating methyl oleate and linoleate, triolein and trilinolein at 180ºC for 5, 10 and 15 hours, were characterized and quantitated after derivation to fatty acid methyl esters by using two base-catalyzed procedures. Structures were identified by GC-MS before and after hydrogenation. A complete recovery of the epoxy compounds was obtained by comparing results from methyl oleate and linoleate before and after trasesterification, and good repeatibility was also attained. Similar amounts of epoxides were found for methyl esters and triglycerides of the same degree of unsaturation, although formation was considerably greater for the less unsaturated substrates, methyl oleate and triolein, possibly due to the absence of remaining double bonds in the molecule which would involve a lower tendency to particcipate in further reactions. On other hand, independently of the degree of unsaturation of the model systems and of the period of heating, significantly higher amounts of  trans isomers were formed. Finally, from comparison between the amounts of epoxides and the level of polar fatty acids in samples, it was deduced that monoepoxy compounds were one of the major groups formed under the conditions used.
 

Berdeaux, O., G. Márquez-Ruiz  and  M.C. Dobarganes
Selection of methylation procedures for quantitation of short-chain glycerol-bound compounds formed during thermoxidation.
Journal of Chromatography A 863 (1999) 171-181.
ISSN: 0021-9673

Abstract: Five methylation procedures, including base- and acid-catalyzed methods, were tested in thermoxidized methyl linoleate and trilinolein, in order to quantitate major oxidation short-chain glycerol-bound compounds by gas chromatography. Results indicated that transmethylations using KOH in methanol or CH3ONa/CH3OH in tert.-butyl methyl ether were the most appropriate methods, given the excellent reproducibility and practically complete recovery obtained for the compounds of interest, mainly short-chain fatty acids and aldehydic acids. Also, formation of acids from aldehydes during thermoxidation as well as modifications of aldehydic functions under acidic conditions, such as conversion to acetals, were checked using dodecanal as model aldehyde.

Borja, R., J. Alba,  A. Martín  y A. Mancha
Estudio cinético del proceso de digestión anaerobia de aguas de lavado de aceitunas de almazara en reactores de mezcla completa con microorganismos inmovilizados.
Grasas y Aceites 50 (1999) 87-93.
ISSN: 0017-3495.

Resumen:  Se ha efectuado un estudio cinético del proceso de digestión anaerobia en régimen continuo de aguas de lavado de aceitunas de almazara en un reactor de mezcla completa utilizando sepiolita como soporte para la inmovilización de los microorganismos responsables del proceso, a la temperatura de 35 °C.  Se utilizan cuatro concentraciones de substrato como alimento, 4,5, 3,5, 2,5 y 1,5 g DQO/l, operando con cada una de ellas en un rango de tiempos de retención hidráulicos de 4,5 a 1,25 días.  Para ello, se aplica el modelo cinético de Michaelis-Menten, obteniéndose los valores de la velocidad máxima de utilización de substrato, k (g DQO/g SSV día), y de la constante cinética del proceso, Ks (g DQO/l), para cada concentración de substrato objeto de estudio. Se observa que estas constantes cinéticas disminuyen de forma significativa al disminuir la concentración de substrato en el alimento, presentando los valores más elevados para la mayor concentración utilizada.  Los coeficientes de producción celular, Yx, y de muerte microbiana, kd, fueron 0,14 g SSV/g DQO y 0,003 días-1, respectivamente.
 

Brenes, M., A. García, P. García, J. J. Ríos and A. Garrido
Phenolic compounds in Spanish olive Oils.
Journal of Agricultural and Food Chemistry 47 (1999) 3535-3540.
ISSN: 0021-8561

Abstract: Phenolic compounds in Spanish virgin olive oils were characterized by HPLC. Simple phenols such as hydroxytyrosol, tyrosol, vanillic acid, p-coumaric acid, ferulic acid, and vanillin were found in most of the oils. The flavonoids apigenin and luteolin were also found in most of the oils. The dialdehydic form of elenolic acid linked to tyrosol and hydroxytyrosol was also detected, as were oleuropein and ligstroside aglycons. The structure of a new compound was elucidated by MS and NMR as being that of 4-(acetoxyethyl)-1,2-dihydroxybenzene. Changes of phenolic compounds in virgin olive oils with maturation of fruits were also studied. Hydroxytyrosol, tyrosol, and luteolin increased their concentration with maturation. No clear tendency was observed for the rest of the phenolic compounds identified.

Canet, M. y J.Mª. García
Repercusión de la frigoconservación de la aceituna de molino en el proceso de producción de aceite de oliva virgen.
Grasas y Aceites  50 (1999) 181-184.
ISSN: 0017-3495

Resumen:  Durante la campaña 1993-94, un total de 1.003.551 Kg de aceitunas (Olea europaea, cvs. Blanqueta y Villalonga) fueron almacenadas en una cámara frigorífica a 5 ºC por un tiempo máximo de 18 días. El aceite virgen obtenido de estas aceitunas mostraba unos índices físico-químicos y una valoración sensorial dentro de los límites establecidos para el aceite virgen "extra". La frigoconservación de la aceituna hizo posible el trabajo a máximo rendimiento de la maquinaria de procesamiento durante 8 semanas, sin que se redujera apreciablemente la calidad del aceite virgen obtenido. Además permite una mejor amortización de los equipos disponibles y, al requerir que el fruto se distribuya en cajas, contribuye en la racionalización de la manipulación postcosecha de la aceituna.

Cantisán, S., E. Martínez-Force,  R. Álvarez-Ortega and R. Garcés
Lipid characterization in vegetative tissues of high saturated fatty acid sunflower mutants.
Journal of Agricultural and Food Chemistry 47 (1999) 78-82
ISSN: 0021-8561

Abstract: Five sunflower (Helianthus annuus L.) mutant lines with high concentrations of saturated fatty acid in the seed oil, three high stearic and two high palmitic, have been studied during their germination and vegetative cycle. No significant variations with regards to the control line were observed in the saturated fatty acid content of the vegetative tissue lipids, however, during seed germination important differences between lines were found. Although in the early steps of germination the palmitic and stearic acid levels in the respective mutants continued being higher than the control, they decreased and reached values similar to the control, except in CAS-3. Variations in the cotyledon palmitic acid content with regards to the control line were also observed in high stearic mutants. All this suggest the expression of a modified acyl-ACP thioesterase during cotyledon development that could be partially involved in the observed phenotype in seeds.
 

Clemente, A., J. Vioque, R. Sánchez-Vioque, J. Pedroche, J. Bautista and F. Millán.
Protein quality of chickpea (Cicer arietinum L.) protein hydrolysates.
Food Chemistry 67 (1999) 269-274.
ISSN: 0308-8146

Abstract: Chickpea protein isolate (CPI) was used as the starting material of chickpea protein hydrolysates (CPHs). To obtain a highly extensive hydrolysate with a degree of hydrolysis higher than 50%, a sequential utilisation of endoprotease (Alcalase) and exoprotease (Flavourzyme) was necessary. Molecular weight patterns of CPHs were determined by gel filtration chromatography. As a result of the enzymatic activity, differences in the chromatographic pattern of CPHs were observed. Although significant decreases of Phe and Arg were observed after hydrolysis, adequate amounts of essential amino acids in relation to the reference pattern of FAO were found. In vitro protein digestibility of CPHs (95%) were similar to that of the starting material (CPI), and TIA was not detected in any case. A high increase of solubility in CPHs, with respect to CPI, was observed, one CPH being totally soluble over a wide pH range (2-10) when the enzymes were added sequentially. Due to their high protein quality and solubility, CPHs might be considered as potential ingredients in the food industry.
 

Clemente, A., J. Vioque, R. Sánchez-Vioque, J. Pedroche  and F. Millán
Production of extensive chickpea (Cicer arietinum L.) protein hydrolysates with reduced antigenic activity.
Journal of Agricultural and Food Chemistry 47 (1999) 3776-3781.
ISSN: 0021-8561

Abstract: Chickpea protein isolate was used as starting material for the production of hypoallergenic protein hydrolysates. Western blotting of the protein isolate showed that IgE in sensitized patient sera strongly bound to the basic polypeptidic chains and recognized the acidic ones of 11S globulin. During the hydrolysis process by the individual and/or sequential action of endo- and exoproteases, a high reduction of antigenic activity was observed. Results suggest that the presence of intact or partially hydrolyzed basic polypeptide chains of 11S globulin are responsible for the formation of IgE complexes in protein hydrolysates obtained by exoprotease treatment; however, the digestion of these polypeptide chains by individual action of endoprotease caused a high loss of antigenic activity. The most effective reduction of antigenicity, >90%, was observed in extensive hydrolyzed chickpea proteins obtained by sequential treatment with endo- and exopeptidases. This chickpea protein hydrolysate could be useful for the elaboration of specialized hypoallergenic food products.
 

Copado M.A.,  V. Ruíz-Gutiérrez and A.R. Burgos
Fatty acids and Squalene carried by  alpha fetoprotein, and fetal and adult serum albumin from chicken. Comparison with these  from manmmals
Journal of Protein Chemistry 18 (4) (1999) 413?424.
ISSN: 0277-8033

Abstract: Alpha fetoprotein (C-AFP), serum albumin (C-fSA) from chicken embryos, and SA from hens were purified using gentle chromatographic and electrophoretic methods, and their fatty acids (FAs) and squalene contents were analyzed using gas chromatography and mass spectrometry. In 7-day-old chick embryo, AFP carries 16% and fSA 6% free FAs, the rest being carried as phospholipids, which differs from rat and pig AFP, where all fatty acids are carried like free fatty acids. At this stage C-AFP contains 3.6% arachidonic acid, which falls to 1.7% in 14-day-old embryos. Both of these figures are significantly lower than in humans, rats, calves, and pigs. C-AFP does not transport docosahexaenoic acid, in notable contrast to the mammals mentioned above. The finding of squalene in the two fetal proteins is reported for the first time. During the interval between 7 and 14 days, the proportion of C16:1 n-7 and of C18:2 n-6 increases 10-fold, that of C18:0 quadruples, and that of C18:1 n-9 decreases 3-fold. Squalene increases in this period from 2.2% to 10.0%. The C-fSA of a 7-day-old embryo transports only one FA with more than two unsaturated carbons, arachidonic acid (2.4%). It also contains squalene (1.2%). Similarly, only arachidonic acid (2.5%), but not squalene is found in hen SA. The percentage of saturated and monounsaturated FAs divided by the percentage of polyunsaturated FAs, and the ratios of the percentage of FAs with C14-C18 with respect to those with C20-C22 transported by C-AFP are very different from those of studied mammals.
 

Dobarganes, M.C.,  A. Cert,  and  A. Dieffenbacher
The determination of stigamastadienes in vegetable oils.
Pure Appl. Chemistry 71 (1999) 349-359.
ISSN: 0033-4545

Abstract: The development by collaborative study of a standardised method for the determination of the stigmastadienes content in vegetable oils is described. The procedure involves the isolation of the unsaponifiable matter in the oil and its fractioning on a silica gel column. The fraction containing the steroidal hydrocarbons is the use of an internal standard/cholestan-3,5-stadiene. The procedure is very sensitive allowing determination at levels of 0.01-4.0 mg/kg.
 
 

Durán Quintana, Mª.C.,  P. García García and A. Garrido Fernández
Establishment of conditions for green table olive fermentation at low temperature.
International Journal of Food Microbiology 51 (1999) 133-143.
ISSN: 0168-1605

Abstract: Four Lactobacillus plantarum strains were isolated from table olive cold fermentation brines. Their specific growth rate and acidification in MRS broth and in green table olive brines were studied by means of a mixed 2 pH (4.5 and 5.0) x 3 salts (3, 4 and 5%, w/v, NaCl) x 3 incubation temperature (9, 12 and 15ºC) levels factorial design. In MRS broth, the greatest effect (linear) on acidification was due to temperature. In brine, the effects were considerably less, pH (linear) being the most important for specific growth rate, and temperature (linear) for acidification. In both media, an initial pH of 5.0 led to good acidification at 12-15ºC. The effectiveness of the conditions found (initial pH of 5.0; 3%, w/v, NaCl; and incubation at 12ºC) was confirmed in simulated green olive fermentations with three of the strains, which proved especially robust. Behaviour in terms of growth and acidification rates was similar for these strains, and comparable to that observed in traditional processes, although mannitol and sucrose were not metabolised and fructose was only partially used. This leads to the possibility of obtaining normal fermentation processes of table olives in cold regions when appropriate initial conditions and starter cultures are used.

.
Fernández-Bolaños, J., B. Felizón, A. Heredia, R. Guillén and A. Jiménez
Characterization of the lignin obtained by alkaline delignification and of the cellulose residue from steam-exploded olive stones.
Bioresource Technology 68 (1999) 121-132.
ISSN: S0960-8524.

Abstract: The lignocellulosic by-products (whole stones and seed husks) obtained from pitted table olive and olive oil processing (respectively) were pre-treated under various conditions of steam-explosion, with respect to pressure and time and with a dilute solution of sulfuric acid and without previous acid impregnation. The two materials exhibited considerable difference in behaviour. The pre-impregnation of whole stones with low level of acid prior to steam treatment was necessary to improve the fractionation and the autohydrolysis of hemicellulose, while the results with seed husks were similar both with and without an acid catalyst. The lignins recovered from water-washed solid residue by alkaline-extraction followed by acidification were characterized. These lignin preparations from whole stones contained a very high amount of fat and almost no neutral sugars. The results also showed that these lignin preparations were guaiacyl-syringyl lignin, similar to exploted hardwood lignin, with an extensive cleavage of the $-aryl-ether linkage. The effect of treatment severity on the major physical properties of cellulose was also investigated. The cellulose fraction derived from steam-exploded whole stones was rapidly depolymerzed as severity increased, leading to a degree of polymerization of 180, at a severity of log Ro = 4.07. In seed husks, under similar severity conditions, depolymerization of cellulose was much slower, and only reached a value of 821 (at log Ro = 4.07) or a value of 600 at log Ro = 4.34 without acid impregnation. The cellulose derived from both steam-exploded materials was moderately crystalline, the relative crystallinity index values of seed husks being higher than those of whole stones. The results indicated that the cellulose from seed husks was more protected than that of the whole stones in the steam-explosion process, and could be used to produce a cellulose with different properties and applications depending on severity and on the different treated material.
 

Gallardo-Guerrero, L., B. Gandul-Rojas  and M.I.Mínguez-Mosquera
Chlorophyll pigment composition in table olives (cv Gordal) with green staining alteration.
Journal of Food Protection 62 (1999) 1167-1171.
ISSN: 0362-028X

Abstract: Metallochlorophyllic complexes of copper are present in green table olives, showing the alteration known as green staining. They were formed stepwise in such a way that new metallochlorophyll derivatives were detected as the fruits became more altered. Cu-15-glyoxylic acid pheophytin a was the first compound formed, followed in order by Cu-pheophytin a, Cu-15-glyoxylic acid pheophytin b, Cu-15-formyl-pheophytin a and Cu-pyropheophytin a. Pigment analysis in fruits classified according to the surface area affected by green staining showed a progressive increase in the concentration of all copper complexes with the course of the alteration. The metallochlorophyll derivatives of copper were present both in the part of the fruit affected by the alteration and in the remainder part, although the amount was significantly greater in the former. On the other hand, not all the copper present in the fruits was accessible for the formation of such compounds, since the concentration of copper complexes found in olives with the maximum degree of alteration observed did not exceed 20% of the total copper of the fruit.
 
 

Gandul-Rojas, B., L. Gallardo-Guerrero and M.I Mínguez-Mosquera
Identification of oxidized chlorophylls¡Error! Marcador no definido. and metallo-chlorophyllic complexes of copper in table olives (cv. gordal) with green staining alteration.
Journal of Food Protection 62 (1999) 1172-1177.
ISSN: 0362-028X

Abstract: In Spanish green table olives showing the alteration known as green staining, new chlorophyll derivatives have been identified: the copper complexes of 31,32-didehydrorhodochlorin-15-glyoxylic acid-173-phytyl ester a and b (Cu-15-glyoxylic acid pheophytins a and b), and 31,32-didehydro-151-hydroxy-151-hydroxyrhodochlorin-15-acetic acid d?lactone-152-methyl-173-phytyl ester a and b (Cu-151-OH-lactone-pheophytins a and b). These compounds were isolated by normal phase thin layer chromatography and identified from their UV-visible and mass spectra and by co-chromatography with authentic standards. The chromatographic and spectroscopic characteristics and the molecular mass for a new allomerized chlorophyll derivative and its copper complex are reported. The corresponding molecular structure according to the molecular mass has been proposed. The characterization of the latter compounds enables their possible detection in processed fruits and vegetables. The present work gathers new advances in the study of the color alteration in table olives and this is the first time that copper complexes of oxidized chlorophylls are detected in foodstuffs.
 

Gandul-Rojas, B., M. Roca López-Cepero and  M.I. Mínguez-Mosquera
Chlorophyll and carotenoid patterns in olive fruits, Olea europaea cv. arbequina.
Journal of  Agricultural and Food Chemistry 47 (1999) 2207-2212.
ISSN: 0021-8561

Abstract: In olive fruits of the Arbequina variety, the chlorophyll pigments decrease significantly throughout ripening, while the carotenoids decrease more gradually and discontinuously. There is no degradation of the carotenoid fraction in stages before complete ripeness. The presence of esterified xanthophylls exclusively in this variety suggests that the chloroplast pigment metabolism is different to that in other olive varieties studied previously. There are increases of specific carotenoids, violaxanthin, neoxanthin, antheraxanthin, lutein epoxide and esterified xanthophylls between the light-green and yellowish-green ripening stages. Such increase is related to the detection of precursor carotenoids (phytofluene and x-carotene) in the yellowish-green stage. Chlorophyllides (a and b) and a-carotene have also been detected exclusively in this variety. Quantitatively, the drastic change in color between light-green and yellowish-green ripening stages characteristic of this variety can be explained by the considerable reduction found in the chlorophylls/carotenoids ratio. The study of the pigments present in skin and pulp has shown that the pattern of carotenoid distribution differs depending on the fruit part concerned.
 

García, P., M. Brenes, C. Romero and A. Garrido
Colour and texture of acidified ripe olives in pouches.
Journal of Food Science 64 (2) (1999) 248-251.
ISSN: 0022-1147

Abstract: The effects of pouch material (aluminium, plastic), packing pH (3.8, 4.3), acidifying compound (lactic, gluconic), and storage temperature were tested on polyphenol content and color of holding brines, surface color, and firmness of ripe olives. Using pouches of plastic films, pH 4.3-4.0 holding solution, and lactic or gluconic acid products with colour and texture similar to traditional canned ripe olives were produced. They could be properly stored at room temperature (25ºC). As storage temperature rose, colour improved but texture was seriously degraded at 50ºC.
 

García-Ayuso, L.E., J. Velasco,  M.C. Dobarganes and M.D. Luque de Castro
Accelerated extraction of the fat content in cheese using a focused microwave-assited soxhlet device.
Journal of Agricultural Food Chemistry  47 (1999) 2308-2315.
ISSN: 0021-8561

Abstract: A fast method for hydrolysis and extraction of fat in cheese based on the use of a Soxhlet extractor assisted by microwaves is proposed. The use of this type of energy dramatically reduces the time required for both steps (namely, the hydrolysis time was decreased from 1h to 10 min with avoidance of the neutralization step, and the extraction time was decreased from 6h to 40 min), providing similar efficiency and reproducibility comparable to or better than that of the conventional Soxhlet methodology. In addition, the proposed method is cleaner than conventional Soxhlet, as 80-85% of the extractant, is recycled. The determination of the fatty acid composition by gas-liquid chromatography and quantification of both polymer formation by high-performance size exclusion liquid chromatography and nonpolar triacylglycerol formation by thin-layer chromatography with flame ionization detection in the extracts obtained by the proposed method, conventional Soxhlet and Weibull-Berntrop procedures (Soxhlet with a prior hydrolysis step), showed that the quality of the extracts obtained by the proposed procedure is better than that of the conventional alternatives, possibly due to the shorter time required by the accelerated method.
 

García García, P., M. Brenes-Balbuena, D. Hornero-Méndez, A. García Borrego and A. Garrido-Fernández
Content of biogenic amines in table olives.
Journal of Food Protection 63 (1999) 111-116.
ISSN: 0362-028X

Abstract: Biogenic amines are low molecular weight organic bases that possess biological activity. The aim of this work was to study the content of biogenic amines in fresh table olive fruits and to follow its changes during the fermentation process of spanish-style green olives and the storage of ripe olives no biogenic amines were found in fresh olives. Putrescine was found in samples of brines taken after three months of brining as well as small amounts of cadaverine. Contents encrease with fermentation time. After twelve months fermentation/storage small amounts histamine, tyramine and tryptamine were also found. Gordal cultivar showed the highest contents, followed by Manzanilla and Hojiblanca. No relationship was found between content of biogenic amines and lactic acid production or table olives spoilages, although zapatera olives had considerably higher amounts than those brines that had undergone a normal fermentation. Concentration in directly brined olives were markedly lower than contents in spanis-style olives. With respect to partition between flesh and brines, there was equilibrium between both media in the case of spanish-style olives, whereas the contents in directly brined olives were higher in flesh than in brine.
 
 

Garrido Fernández, A.  y C. Romero Barranco
Calidad de las aceitunas de mesa
Grasas y Aceites 50  (1999) 225-230.
ISSN: 0017-3495

Resumen: El trabajo comenta las diferentes normas, tanto nacionales como internacionales, que regulan los aspectos de la calidad de las aceitunas de mesa. Se comentan especialmente la Norma Cualitativa unificada Aplicable a Aceitunas de Mesa en el Comercio Internacional y las correspondientes COI/CODEX (Consejo Oleícola Internacional, COI, y COI/Codex Alimentarius, respectivamente), la Reglamentación Técnico Sanitaria para la elaboración, circulación, y venta de aceitunas de mesa (española), Las Normas de calidad para la exportación de Aceitunas de Mesa (española), y las “United Standards for Grades of Green and Canned Ripe Olives” (USA). Asimismo se analizan las implicaciones de las nuevas reglamentaciones sobre etiquetado nutricional (principalmente en el comercio con USA), la aplicación del Análisis de Riesgos y Control de Puntos Críticos (ARCPC), y la necesidad de adaptar el Sector al cumplimiento de las diversas normas de la serie ISO 9000 o su equivalente EN 29000.
 

Gutiérrez, F.,  T. Arnaud and M.A. Albi
Influence of ecological cultivation on virgin olive oil quality
Journal of the American Oil Chemists’Society 76 (1999) 617-621.
ISSN: 0003-021X

Abstract: The quality of oil extracted from ecologically cultivated olives of the Picual variety olives cultivated using conventional methods. Olive trees grown in a two –section plot. Fruits from each plot were harvested at various stages of ripeness, and acidity value, peroxide index, ultraviolet absorption at 232 and 270 nm, stability to oxidation, sensory analysis, fatty composition, and contents of tocopherols , phenolic compounds, and sterols were determined in oils extracted from each treatment. The results showed that the organic virgin olive oil was a superior quality to the conventional virgin olive oil  in all the quality parameters analyzed.
 

Gutiérrez, F., B. Jiménez,  A. Ruiz and M.A. Albi
Effect of olive ripeness on the oxidative stability of virgin olive oil extracted from the varieties Picual and Hojiblanca and on the different components involved.
Journal of  Agricultural and  Food Chemistry  47 (1999) 121-127.
ISSN: 0021-8561

Abstract: The initial stability of virgin olive oil depends on various factors, among which are the variety and degree of fruit ripeness. The former, which genetically determines the composition of olive and its oil, also marks, to some extent, its stability. However, oil stability  changes as the olive ripens, so it obvious that the degree of ripeness is a important factor. The oils were obtained by the Abencor system. Acidity, peroxide index, UV absorption  at 232 and 270 nm, sensory analysis, fatty acid composition, tocopherols, phenolic compounds, orthodiphenolic compounds, sterols, pigments and oxidative stability were determined, and the results were analized statistically. During ripening there was a decrease in all of the parameters studied except linoleic acid, D-5 avenasterol. And oil content, which increased. Virgin oils showed very good correlation between stability and the concentrations of total phenols, o-diphenols, tocopherols, chlorophyll pigments and carotenoids, linoleic and linolenic acids, total sterols, b-sitosterol and D-5 avenasterol.

Hidalgo, F. J., M. Alaiz and R. Zamora
Effect of pH and temperature on comparative nonenzymatic browning of proteins produced by oxidized lipids and carbohydrates
Journal of Agricultural and Food Chemistry 47 (1999) 742-747.
ISSN: 0021-8561

Abstract: Bovine serum albumin (BSA) was incubated for 24 h in the presence of 10 mM ribose (RI), methyl linoleate hydroperoxides, or the secondary products of methyl linoleate oxidation (SP), at five temperatures (25, 37, 50, 80, and 120 ºC) and different pHs (4, 7, and 10), to study the influence of these variables in the browning, fluorescence, amino acid losses, and pyrrolization of the modified proteins. All treated proteins exhibited similar colors and fluorescence spectra, and the spectra of their Ehrlich adducts were also analogous. However, at 25-50 ºC the proteins treated with oxidized lipids exhibited higher color changes, amino acid losses, and pyrrolization than the BSA treated with RI, and these effects were much higher in proteins treated with RI at 80-120 ºC. The effect of pH was similar in proteins treated with RI or SP. These results suggested a similarity for browned proteins obtained from both carbohydrates and oxidized lipids. In addition, both reactions seem to be complementary, because melanoidin formation derived from oxidized lipids can be produced under conditions different from those carbohydrate/protein reactions.
 

Jarén-Galán, M. A. Pérez-Gálvez and M.I. Mínguez-Mosquera
Prediction of decoloration in paprika oleoresins. Application to studies of stability in thermodynamically compensated systems.
Journal of  Agricultural and Food Chemistry 47 (1999) 945-951.
ISSN: 0021-8561

Abstract: In six paprika oleoresins, the kinetic parameters for the decoloration reaction at three temperatures have been established. The thermodynamic study shows that the decoloration reaction in each oleoresin has its own activation entropy (DS) and activation enthalpy (DH). The six reactions studied show a constant ratio between DH and DS, which means that each reaction is an isokinetic form of only one reaction affected by thermodynamic compensation. Instead of one equations per oleoresin to predict pigment concentration as a mathematical function of time and temperature, one unique equation can be obtained in which DH is function of DS. The validity of this equation has been tested comparing the actual concentration remaining during a heat treatment and the calculated one. More than 90% of the calculated concentration are within the range of variability of the actual mean. Due to the reduction in the number of variables in thermodynamic compensated systems, it is proposed a general procedure to calculate the activation entropy in isokinetic reactions.
 

Jarén-Galán, M. and M.I. Mínguez-Mosquera
Effect of pepper lipoxygenase activity and its linked reactions on the pigments of the pepper fruit.
Journal of Agricultural and Food Chemistry 47 (1999) 4532-4536
ISSN: 0021-8561

Abstract: The products formed during the enzymatic reaction catalyzed by the lipoxygenase of pepper (variety Agridulce) have in vitro a strong destructive action on the carotenoid pigments of the fruit. When conditions and proportions of enzyme and pigments are similar to those found in the fruit, and at a reaction temperature of 20oC, almost 30 % of the pigments are destroyed after 24 h of reaction. Of this amount, 2.5% is due to autoxidation of pigments, 4.5% to oxidation induced by the presence of linoleic under saturating conditions, and the remaining 22 % to the presence in the medium of reaction products of the lipoxygenase-catalyzed reaction. When the enzyme acts under substrate-saturating conditions, the rate of pigment destruction by lipoxygenase can be considered maximal at the experimental temperature. The fact that in vitro pepper lipoxygenase induces a heavy destruction of pigments, and that in vivo, its activity remains almost constant during over-ripening, could explain why up to 40% of the pigment content in some varieties is lost during the post-harvest period.
 

Jarén-Galán, M. and M.I. Mínguez-Mosquera
Quantitative and qualitative changes associated with heat treatments in the carotenoid content of paprika oleoresins.
Journal of Agricultural and Food Chemistry 47 (1999) 4379-4383
ISSN: 0021-8561

Abstract: Quantitative changes in the red and yellow carotenoid pigment fractions of four paprika oleoresins were studied at four storage temperatures. At all four temperatures, there was an overall loss of pigmentation, which was more marked with increasing temperature. However, pigmentation loss was not qualitatively uniform. At temperatures below 60° C, the rate of destruction of the yellow pigment fraction was higher than that of the red pigments. Above 60° C, the order of lability of the two fractions was inverted, and the red pigment fraction became the more unstable. Thus, treatments above this temperature increase the proportion of yellow pigments. Any heat treatment results in a decrease in the total pigment concentration, with the initial proportion of red and yellow pigments switching in favour of one or the other depending on the temperature used.
 

Jarén-Galán, M., C. Carmona-Ramón and M.I. Mínguez-Mosquera
Interaction between chloroplast pigments and lipoxygenase enzymatic extract of olives.
Journal of Agricultural and Food Chemistry 47 (1999) 2671-2677
ISSN: 0021-8561

Abstract: Lipoxygenase activity in olive fruits increases considerably when the enzyme is extracted using extraction buffer with ethylenediaminetetraacetate, Triton X-100, dithiothreitol, sodium meta-bisulfite and hydrated polyvinylpolypyrrolidone. In absence of these compounds the activity measured of the crude extract is almost negligible and the further effects of the enzymatic reaction, such as bleaching activity on chloroplast pigments, do not appear. Moreover, when the oxidizing level of the medium is increased by the addition of linoleic acid or soybean lipoxygenase with linoleic acid, the crude enzymatic extracts of olives reduce the destructive capacity of soybean lipoxygenase on chlorophylls to 1/6. These results suggest a double pigment protection against lipoxygenase in the olive crude extract, one inhibiting the enzyme and other interrupting the chain of oxidative reactions beginning with hydroperoxide formation.
 

Jarén-Galán, M., U. Nienaber and S.J. Schwartz
Paprika (Capsicum annuum) oleoresin extraction with supercritical carbon dioxide
Journal of Agricultural and Food Chemistry 47 (1999) 3558-3564.
ISSN: 0021-8561

Abstract: Paprika oleoresin was fractionated by extraction with supercritical carbon dioxide (SCF-CO2).  Higher extraction volumes, increasing extraction pressures, and similarly, the use of cosolvents such as 1% ethanol or acetone resulted in higher pigment yields.  Within the 2000-7000 psi range, total oleoresin yield always approached 100 % each time. Pigments isolated at lower pressures consisted almost exclusively of b-carotene, while the pigments obtained at higher pressures contained a greater proportion of red carotenoids (capsorubin, capsanthin, and zeaxanthin) and small amounts of b-carotene.  The varying solubility of oil and pigments in SCF-CO2 was optimized to obtain enriched and concentrated oleoresins through a two-stage extraction at 2000 psi and 6000 psi. This technique removes the paprika oil and b-carotene during the first extraction step, allowing for second-stage oleoresin extracts with a high pigment concentration (200 % relative to the reference) and a red:yellow pigment ratio of 1.8 (compared to 1.3 in the reference).
 

Lanzón A. T. Albi,  and A. Guinda
Formation of a D 7 triterpene alcohol in refined olive oils.
Journal of the American Oil Chemists´ Society 76 (1999) 1421-1424.
ISSN: 0003-021X

Abstract: The triterpene alcohol fraction in several virgin olive oils and corresponding refined oils by alkali and physical refining process was analyzed by gas chromatography. A D7 compound  was detected in all refined olive oils but not in virgin olive oils. This compound was tentatively identified by gas chromatography - mass spectrometry (GC-MS)  as being 24-methyl-5D-lanosta-7,24-dien-3D-ol. It is a 24-methylencycloartanol  isomer produced during the refining process by the opening of the 9,19 cyclopropane ring with formation of a double bond in the D7 position and the translocation of a double bond in the side chain   from the 24-28  to the 24-25 position.
 

León Camacho, M.,  Mª.V. Ruiz-Méndez and  E. Graciani Constante
Isomerisation of fatty acids during deodorization / physical refining stripping with nitrogen.
Fett Lipid 101 (1999) 290-294
ISSN: 0931-5985

Abstract: A gas-liquid chromatography study has been carried out on the methyl esters of trans fatty acids formed by isomerization of the corresponding cis fatty acids during the deodorization of edible oils. Conclusions are drawn as to the best way of presenting the results to give useful information on the alterations undergone by the natural fatty acids of olive, sunflower, and soybean oils during deodorization. The results can be used to compare the effects of treatments, whether the same or different, on the three types of edible oil tested. Nitrogen was used as stripping gas in the deodorization.
 

León Camacho, M., Mª.V. Ruiz-Méndez  and E. Graciani Constante
Changes in olive oil components during deodorization and/or physical refining at the pilot plant scale using nitrogen as stripping gas.
Fett Lipid 101 (1999) 38-43
ISSN: 0931-5985

Abstract: A detailed study has been made of the changes produced by the action of the independent variables (temperature, flow of stripping gas, thickness of oil layer in the deodorizer, and length of the process) on different quality parameters of olive oil deodorized and/or physically refined in discontinuous process (in a pilot plant of 250 Kg maximum capacity using nitrogen as stripping gas in place of steam). The changes produced in the unsaturated fatty acids (elaidization), in the contents of 3,5-stigmastadiene (dehydrated beta sitosterol) and saturated fatty acid in the beta position have been studied. A bleached olive oil with 1.8º of acidity was used in a 23 centred cube experimental scheme The results obtained were compared with those from similar assays carried out with bleached sunflower seed oil with 0.56º of acidity (using a 4x4 latin square experimental scheme). It is concluded that  the content in trans fatty acids of the deodorized oils depends indirectly on the four variables, and although the elaidic content is correct in all cases, the trans content of 18:2 and 18:3 readily exceeds the permitted limit when the temperature is above 250 ºC and the residence times are long. The same occurs with the content of saturated fatty acids in beta position of triglyceride and 3,5-stigmastadiene. This means that the oil must be deodorized at lower temperature, with longer residence time and greater energy spending. As the different olive oils have different initial characteristics, it is of interest to establish criteria able to forecast whether a particular oil could be refined under pre-set conditions. Similar study should be made to obtain refined oils in other plants.
 

.
Márquez-Ruiz, G., M. Martín-Polvillo,  N. Jorge, Mª.V. Ruiz-Méndez and M.C. Dobarganes
Influence of used frying oil quality and natural tocopherol content on oxidative stability of fried potatoes.
Journal of the American Oil Chemists’ Society 76 (1999) 421-425.
ISSN: 0003-021X

Abstract: Sunflower oil (SO) and high-oleic sunflower oil (HOSO) were used to prepare fried potatoes by either discontinuous and continuous laboratory frying. Fried potatoes differing in oil quality were stored at 60ºC for up to 30 days and evaluated for polar compounds, polymers, peroxide value, oil stability index and  a-tocopherol content. Results obtained through the various methods applied were consistent and indicated that the length of the induction period could not be explained only on the basis of the degree of unsaturation or polar compounds levels in fried potatoes before storage. a-tocopherol content had also a significant influence as potatoes fried in HOSO, with 16% polar compounds and only 10 mg/Kg  a-tocopherol at the starting point of storage, were oxidized more rapidly than potatoes fried in SO with a comparatively higher degradation level, 19% polar compounds,  and 100 mg/Kg  a-tocopherol.
 

Márquez-Ruiz, G., R. Garcés,  M. León-Camacho and M. Mancha
Thermoxidative stability of triacylglycerols from mutant sunflower seeds.
Journal of the American Oil Chemists’Society 76 (1999) 1169-1173.
ISSN: 0003-021X

Abstract: Thermoxidative stability was evaluated in triacylglycerols (TAG) from the oils of the mutant sunflower lines CAS-3, CAS-4 and CAS-8, with high-stearic-acid percentage, and CAS-5, with high-palmitic-acid percentage, all in a standard high-linoleic genetic background, and the mutant sunflower line CAS-12, with high-palmitic-acid percentage in a high-oleic genetic background. These oils contained unusually high contents of TAG molecular species with one and two saturated fatty acids at the sn-1,3 positions. Purified total TAG devoid of tocopherols were subjected to controlled thermoxidative treatment at 180ºC. Polymerized TAG were determined at 2-h intervals for 10 h. After this time, total polar compounds, oxidized TAG monomers, TAG dimers and TAG oligomers were determined. TAG from the highly saturated sunflower oils with levels of linoleic acid similar to those in the conventional sunflower oil (40-50%), showed enhanced thermal stability. In these TAG, the amounts of polar compounds formed during the thermoxidative treatment were similar to those formed in the high-oleic-acid line. Excellent results were obtained for the TAG of the CAS-12 oil, which had the highest thermal stability, producing half the amount of polar compounds as the conventional line and less than two-thirds that of the high-oleic line.
 

Martínez Román, F., Mª J. Moyano Pérez.,  J. Alba Mendoza., Mª A. Ruiz Gómez., F. Hidalgo Casado y F.J. Heredia Mira
Método rápido de obtención de aceite de oliva virgen para determinación de acidez
Grasas y Aceites 50 (1999) 122-126.
ISSN: 0017-3495.

Resumen: Se propone un método rápido y sencillo para obtener, a partir de muestras de aceitunas, suficiente cantidad de aceite para determinar su grado de acidez. A partir de muestras de pasta de aceitunas molidas se separan distintas fracciones que se someten a un proceso de centrifugación a 4500 rpm durante 5 minutos. Se comparan los resultados de acidez de los aceites obtenidos de las muestras con adición de microtalco natural y sulfato sódico anhidro, con muestras testigo, así como con el procedimiento de extracción Abencor. Se analiza también la correlación entre la acidez de muestras de aceite obtenidas por el método Abencor, con otras obtenidas por el método normalizado en España, norma UNE 55070, basado en la extracción en la extracción del aceite por el método Soxhlet. Los resultados ponen de manifiesto que en las muestras centrifugadas se obtiene cantidad suficiente para la determinación del grado de acidez, que el tratamiento con sulfato sódico anhidro consigue mayor porcentaje de recuperación, y que, en los tres casos, la acidez presenta buena correlación con la del sistema Abencor, duplicando el número de muestras analizadas respecto a este método. Así mismo, se demuestra que el valor de acidez obtenido al aplicar la norma UNE 55070 es aproximadamente 0,3 grados por encima del obtenido por el sistema Abencor.
 

Martínez-Force, E., R. Álvarez-Ortega and R. Garcés
Enzymatic characterization of high palmitic sunflower (Helianthus annuus L.) mutants.
Planta 207 (1999) 533-538.
ISSN: 0032-0935

Abstract: Two high-palmitic acid sunflower (Helianthus annuus L.) mutants, CAS-5 and CAS-12, have been biochemically characterized. The enzymic activities found to be responsible for the mutant characteristics are beta-keto-acyl-acyl carrier protein synthetase II (KASII; EC 2.3.1.41) and acyl-acyl carrier protein thioesterase (EC 3.1.2.14). Data suggest that the high-palmitic acid phenotype observed in both mutant lines is due to the combined effect of a lower KASII activity and a higher thioesterase activity with respect to palmitoyl-acyl carrier protein (16:0-ACP). The level of the latter enzyme appeared to be insufficient to hydrolyse the produced 16:0-ACP completely and, as a consequence, 3 new fatty acids appeared: (Delta9 Delta12). These fatty acids should be synthesized from palmitoyl-ACP or a derivative by the action of the stearoyl-ACP desaturase, fatty acid synthetase II and oleoyl-phosphatidylcholine desaturase, respectively.
 

Martínez-Force, E., S. Reddy and J.A. Wise
Systematic mutagenesis of the fission yeast Srp54 protein.
Current Genetics 35 (1999) 88-102.
ISSN: 0172-8083

Abstract: The signal recognition particle (SRP) is a ribonucleoprotein required for targeting a subset of nascent pre-secretory proteins to the endoplasmic reticulum membrane. Of the six SRP polypeptides, the most highly conserved is Srp54p, a modular protein consisting of an amino-terminal (N) domain of unknown function, a central GTPase (G) domain, and a carboxyl-terminal (M) domain implicated in the recognition of both signal sequences and SRP RNA. To identify regions of Srp54p that interact with other SRP subunits or regulatory proteins, we carried out systematic mutagenesis of the fission yeast homology, principally using a "clustered charged-to-alanine" strategy. Of the 35 alleles examined, 13 are unable to support growth, two confer cold-sensitivity, five confer heat-sensitivity, and 15 produce no discernible phenotype. The lethal and conditional mutations map throughout the protein to several conserved regions, confirming that these motifs play critical roles in Srp54p function. The effects of the amino-acid substitutions are analyzed with reference to the recently determined tertiary structures of the N/G domain and the intact protein from a thermophilic bacterium.
 

Milán, Z.,  E. Sánchez,  R.  Borja,  K. Ilangovan, A. Pellón,  N. Rovirosa,  P. Weiland  and R. Escobedo.
Deep bed filtration of anaerobic cattle manure effluents with natural zeolite.
Journal of Environmental Science and Health, B34, 2 (1999) 305-332.
ISSN: 0360-1234.

Abstract:  This study was carried out in a pilot plant for the treatment of anaerobic cattle manure waste. The pilot plant consisted of a semicontinous anaerobic reactor, a settling tank, a filtration process and an ionic exchange column. The study was focused on the filtration process, with natural zeolite as filtering material. In the filtration process different media sizes of natural zeolites packed in columns were tested.  The ranges of media size were 0.4 – 1.0, 1.0 – 3.0 and 3.0 - 5.0 mm. Filtration systems operated by gravity flow from 2 to 10 m3m-2h-1.   The process control was done by assays of solids, turbidity, total and soluble COD, ammonium and orthophosphate. The results showed a better behavior in the filters packed with a media size range between 1.0 and 3.0 mm, operating at 7m3m-2h-1 ,principally when effluent gross particles were previously retained in an Heterogeneous Media Filter, operating at 4 m3m-2h-1. The head losses diagrams in the filter runs were obtained, at each operational conditions. The hydraulic behavior of traditional silica sand and natural zeolite beds were compared at the same operational conditions.
 

Morales, M.T., F. Angerosa and R. Aparicio
Effect of the extraction conditions of virgin olive oil on the lipoxygenase cascade: Chemical and sensory implications.
Grasas y Aceites  50  (1999) 114-121.
ISSN: 0017-3495

Abstract: The volatile compounds produced through the lipoxygenase cascade are responsible for the most remarkable sensory attributes of virgin olive oil. The paper analyses the evolution of these compounds according  to different conditions of temperature and time of the malaxing process. The influence of these parameters on the production of C6 and C5 volatile compounds is stated together with the effect that the amount of these compounds has on the most remarkable virgin olive oil sensory descriptors (green, bitter-pungent, sweet and undesirable). Optima values of temperature and time are given for producing high sensory quality virgin olive oils. Three cultivars, Spanish Picual and Italian Frantoio and Coratina were characterised by sensory attributes and volatile compounds quantified by two different methodologies in order to avoid that results could be circumscribed to a specific cultivar or a quantification method.
 

Morales, M.T. and R. Aparicio
Effect of extraction conditions on sensory quality of virgin olive oil
Journal of the American Oil Chemist’Society 76  (1999) 295-300.
ISSN: 0003-021X

Abstract: The extraction condition of virgin olive oil have a great influence on its sensory quality. During the centrifugation process, temperature and time of malaxing can be altered to potentially affect quality. Malaxing times (15, 30, 45, 60, and 90 min )and temperatures (25 and 35ºC) were studied in an experimental oil mill. Volatile compounds, produced through the lipoxygenase pathway (hexanal, Z-3-hexenal, E-2-hexenal,hexyl acetate, Z-3-hexenyl acetate,hexan-1-ol, E-3-hexen-1-ol,Z-3-hexen-1-ol, and E-2-hexen-1-ol),were analyzed by dynamic head space gas chromatography, gas chromatography-mass spectrometry, and gas chromatography-olfatometry. Different amounts of volatiles responsible for positive attributes of green aroma and negative attributes of astringent mouthfeel of virgin olive oil were determined. The results, after applying mathematical procedures, showed that a temperature of 25ºC and a malaxing time between 30 and 45 min produced volatile compounds that contribute to the best sensory quality. High temperature (T> 35ºC) with minimum values of time (t < 30 min) could also be useful as an alternative way to obtain pleasant green virgin olive oils.
 

Moyano, Mª. J.,  M. Melgosa., J. Alba., E. Hita  and  F.J. Heredia
Reliability of the bromthymol blue  method for color in virgin  olive oils.
Journal of the American Oil Chemists’Society 76 (6) (1999) 687-692.
ISSN: 0003-021X

Abstract: The bromthymol blue (BTB) method is currently used for the assessment of colour in olive and seed oils by visual comparison with standard solutions. Two BTB scales were prepared with 2 yr difference and compared, and the recent one was used to analyse 502 virgin olive oil samples, obtained by the Abencor technique reproducing the industrial procedure.The temporal chromatic degradation of the BTB samples after 2 yr [3.93 Commission Internationale de L’Eclairage (CIE) 1976-(L*a*b*) (CIELAB) units, on the average], as well as the small percentage of virgin olive oils matching the colours of the samples provided by the BTB scales (13.1% with a suprathreshold color tolerance of  1.52 CIELAB units), indicates the limitations of BTB method. Linear regression models are proposed in order to compute with acceptable accuracy the BTB indices from chromaticparameters. The  use of CIELAB for the specification and future studies on colour in virgin olive oils is recommended.
 

Pérez, A.G.,  C. Sanz,  J.J. Ríos,  R. Olías, and J.M. Olías
Effects of ozone treatment on postharvest strawberry quality.
Journal of Agricultural and Food Chemistry 47 (1999) 1652-1656.
ISSN: 0022-5142

Abstract:  The effect of ozone treatment on the postharvest quality of strawberry was evaluated. Strawberry fruits (Fragaria x ananassa Duch. cv. Camarosa) were stored  at 2°C in an atmosphere containing ozone (0.35ppm).  After three days at 2°C, fruits were moved to  20°C to mimic retail conditions (shelf-life).  The changes in several quality parameters such as fungal decay, color, sugar and acids distribution, and aroma were evaluated during strawberries shelf-life.  Ozone treatment was ineffective in preventing fungal decay in strawberries after four days at 20°C.  Significant differences in sugars and ascorbic acid content were found in ozone treated strawberries.  At the end of cold storage,  vitamin C content of ozonated strawberries was three times that of control fruits.  A detrimental effect of ozone treatment on strawberry aroma was observed, with a 40% reduced emission of volatile esters in ozonated fruits.
 

Pérez, A.G., C. Sanz,  R. Olías and J.M. Olías
Lipoxygenase and hydroperoxide lyase activities in ripening strawberry fruits.
Journal of Agricultural and Food Chemistry  47 (1999) 249-253.
ISSN:  0022-5142

Abstract:  The enzymes lipoxygenase and  hydroperoxide lyase have been identified in strawberry (Fragaria x ananassa Duch.) var. Camarosa.  Their subcellular localization, substrate preference and product specificity were determined in mature strawberry fruits.  The activity of both enzymes was located mainly in the microsomal fraction.  Linolenic acid was the preferred substrate for strawberry lipoxygenase, forming 13- and 9-hydroperoxides of this acid in proportion 70:30.  The strawberry hydroperoxide lyase cleaves 13-hydroperoxide of linoleic (13% relative activity)  and linolenic (100% relative activity) acids to form hexanal and (3Z)-hexenal, respectively.  Both enzyme activities and endogenous content of volatile aldehydes formed by sequential action of lipoxygenase-hydroperoxide lyase were evaluated during strawberry development and ripening. A sequential enzymatic pathway for the formation of green odor compounds in strawberry is proposed.
 

Pérez, A.G., R. Olías,  J.M. Olías  and  C. Sanz
Biosynthesis of 4-hydroxy-2,5-dimethyl-3(2H)-furanone and derivatives in  vitro grown strawberries.
Journal of Agricultural and Food Chemistry  47 (1999) 655-658.
ISSN:  0022-5142

Abstract:  The biosynthesis of 2,5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol), and its methyl ether, and glucoside derivatives has been studied in strawberries.  An in vitro system was used for growing this fruit, showing that the presence in the incubation medium of sucrose or hydroxyquinoline hemi-sulfate has not effect on the bioformation of these compounds.  Strawberries in vitro-grown showed an increase in furanone contents along time, especially between the second and fourth days, to the same extent as field-grown fruits but at a higher rate. Among the precursors added to the incubation medium, D-fructose gave rise to an increase in furaneol and its glucoside derivative of 42.6% and 26.3%, respectively.  D-fructose-6-phosphate seems to be the precursor of furaneol in strawberries since, when present in the incubation medium, it produced an average increase of 125% in all furanones contents respect to control fruits.
 

Pérez-Camino, M.C. and A. Cert
Quantitative determination of hydroxy pentacyclic triterpene acids in vegetable oils.
Journal of Agricultural and Food Chemistry  47 (1999) 1558-1562.
ISSN: 0021-8561

Abstract: A simple and precise analytical method for the determination of hydroxy pentacyclic triterpene acids (HPTAs) in vegetable oils was developed. The acidic fraction was isolated by solid-phase extraction using bonded aminopropyl cartridges, and the extract was silylated and analyzed by gas chromatography. Repeatability and recovery of the method were determined. In virgin olive oils, similar amounts of oleanolic (3b-hydroxyolean-12-en-28-oic) and maslinic (2a,3b-dihydroxyolean-12-ene-28oic) acids and traces of ursolic (3b-hydroxyurs-12-en-28-oic) acid were found. The main factor affecting HPTA concentration was the oil quality since that increases as the quality decreases, while olive variety, olive ripeness, and oil extraction system had less influence. In crude olive pomace oils, the concentrations were very much higher than in virgin olive oils. During refining processes, total or significant losses of HPTAs were observed. Esterified derivatives of HPTAs were not found.
 

Pérez-Gálvez, A., J. Garrido-Fernández, M.I. Mínguez-Mosquera, M. Lozano-Ruiz  and V. Montero-de-Espinosa.
Fatty acids composition of two new pepper varieties (Capsicum  annuum L. cv. jaranda and jariza). Effect of drying process and nutritional aspects.
Journal of the American Oil Chemists´Society 76 (1999) 205-208.
ISSN: 0003-021X

Abstract: Different quantitative composition in fatty acids of the pericarp and seeds of two new pepper fruits (Capsicum annuum L. Cv. jaranda and jariza) and the incidence of the different processing stages for paprika is shown. In the pericarp the PUFA linoleic and linolenic, both in the same proportion, are the major acids while in the seed is linoleic, and in a very high concentration than showed in the pericarp. It must point up that the pericarp, an storage zone of carotenoid pigments although contains an important presence of linolenic acid, this acid does not participate in the esterification process, so that esterification would be less useful. From the different lipid pattern are deduced nutritional aspects. In the drying step the concentration levels are constant in the seed while in the pericarp, there is a net increase in the total content of fatty acids, so biosynthetic process are not rejected.
 

Pérez-Gálvez, A., J. Garrido-Fernández and M.I. Mínguez-Mosquera
Participation of pepper seed in the stability of paprika carotenoids.
Journal of the American Oil Chemists´Society 76 (1999) 1449-1454.
ISSN: 0003-021X

Abstract: The degradation of carotenoid pigments present in dried, milled pepper fruit in the absence and presence of different proportions of seed was studied; the reaction was performed at 70ºC in an oven. During the useful life of the product, the thermodegradation reaction rate is inversely proportional to the percentage of seed in the mixture. Beyond that period, the mixtures with lower proportion of incorporated seed lose pigmentation more slowly with increasing reaction time. Taking the experiment as a whole, the value of the reaction rate inverts, and is higher the greater the amount of seed. The presence of higher seed levels, involving the addition of unsaturated fatty acids (mainly linoleic) prone to oxidation, implicates negative effects at prolonged conservation time, only detectable when the product has not commercial validity. Finally, in a mixture reproducing a commercial paprika, the effect is determined of the presence of some 40% of seed on the behavior of the red and yellow pigment fractions under the experimental degradation conditions. At the same time, isomer-forming reactions are examined.
 

Perez-Vich, B., R. Garcés and J.M. Fernández-Martínez
Genetic control of high stearic acid content in the seed oil of sunflower mutant CAS-3.
Theoretical and Applied Genetics 99 (1999) 663-669.
ISSN: 0040-5742

Abstract: A sunflower oil rich in stearic acid (C18:0) may improve substantially its quality for food applications. A sunflower mutant with a high C18:0 (250 g Kg-1) content, named CAS-3, has been recently developed. The objective of this research was to study the genetic control of the high C18:0 trait in this mutant, before it can be effectively used in a breeding program. The mutant was reciprocally crossed with the lines HA-89 (50 g Kg-1 C18:0) and RDF-1-532 (80 g Kg-1 C18:0), the latter being the parental line from which CAS-3 was isolated. A partial dominance of low over high C18:0 content and a control mainly gametophytic was observed from the analysis of the F1 seeds in these crosses. Gas-liquid chromatography analyses of seed oil fatty acids from the BC1F1 and F2 generations from crosses with the original parental line RDF-1-532 indicated a one-gene inheritance for the high C18:0 content. The locus was designated ES1, showing two alleles with a partial dominance of low over high C18:0. The data for C18:0 content in the F2 seeds of the HA-89 x CAS-3 cross satisfactorily fit a 1:14:1 phenotypic ratio. The F2 segregation ratio and the analysis of the BC1F1 and F3 seeds indicated that a second locus was segregating in crosses with HA-89. This locus was designated ES2, was acting in an additive manner, and its influence on the C18:0 content was lower than that of the ES1 locus. It was concluded that the recessive allele es2 was already present in the RDF-1-532 line, the allele es1 being the result of a mutation from ES1. Therefore, the proposed gentotype of the lines CAS-3, RDF-1-532 and HA-89 was es1es1 es2es2, ES1ES1 es2es2, and ES1ES1 ES2ES2, respectively. The knowledge of the inheritance of the C18:0 content in sunflower will efficiently assist in the development of high C18:0 sunflower hybrids.
 

Perez-Vich, B., J. Fernandez,  R. Garcés,  and  J.M. Fernandez-Martínez
Inheritance of high palmitic acid content in the seed oil of sunflower mutant CAS-5.
Theoretical and Applied Genetics 98 (1999) 496-501.
ISSN: 0040-5742

Abstract: Sunflower genotypes with increased level of palmitic acid (C16:0) in the seed oil could be useful for food and industria1 applications. The objective of the present study was to determine the inheritance of the high C16:0 content in the sunflower mutant line CAS-5 (> 25% of the total oil fatty acid). This mutant was reciprocally crossed with the line HA-89 (5.7% C16:0) and BSD-2-691 (5.4% C16:0) the latter being the parental line from which CAS-5 was isolated. No maternal effect for the C16:0 content was observed from the analysis of F1 seeds in any of the crosses. The inheritance study of the C16:0 content in F1, F2 and BC1F1 seeds from the crosses of CAS-5 with its parental line BSD-2-691 indicated that the segregation fitted a model of two alleles at one locus with partial dominance for the low content. The analysis of the fatty acid composition in the F2 populations from the crosses with HA-89 revealed a segregation fitting a ratio 19:38:7 for low (<75%), middle (7.5-15%), and high (>25%) Cl6:0 content, respectively. This segregation was explained on the basis of three loci (P1, P2, P3) each having two alleles showing partial dominance for low content. The genotypes with a high C16:0 content were homozygous for the recessive allele p1 and for at least one of the other two recessive alleles, p2 or p3. This model was further confirmed with the analysis of the F3 and the BCF1 generations. It was concluded that both the recessive alleles p2 and p3 were already present in the BSD-2-691 line, the allele p1 being the result of a mutation from P1. This genetic study will facilitate breeding strategies associated with the incorporation of the high C16:0 trait into agronomically acceptable sunflower hybrids.
 

Perona S.J., V. Ruíz-Gutiérrez  and  L.J.R. Barrón
La cromatografía líquida de alta  eficacia en la separación de triglicéridos grasas compleja
Grasas  y  Aceites 50 (1999) 298-311.
ISSN: 0017-349

Resumen: Los triglicéridos son la fracción lipídica más abundante y al mismo tiempo más compleja de la naturaleza. Por esta razón, es esencial la determinación de sus especies moleculares, así como conocer la posición estereospecífica en que se sitúan los ácidos grasos que los componen, para caracterizar las grasas animales y los aceites vegetales. La técnica más comúnmente empleada con este fin es la cromatografía líquida de alta eficacia (HPLC), en general utilizando columnas de fase reversa. En el presente artículo se describen las condiciones operativas que actualmente se emplean para alcanzar la óptima resolución de picos cromatográficos de triglicéridos, así como la situación actual del conocimiento en materia de separación de especies moleculares de mezclas de triglicéridos complejas, tales como la grasa láctea, el aceite de pescado y la grasa hepática, que son de importancia en el sector industrial y en la nutrición humana.
 

Perona,  S.J. and  V. Ruiz-Gutiérrez
Characterization of the triacylglycerol molecular species composition of fish oil by reverse-phase high performance liquid chromatography.
J. Liquid Chromatog.and Related Technol. 22 (1999) 1699-1714
ISSN: 1082-6076

Abstract: The nutritional benefits attributed to fish oils have been the basis for the study of the structural component. of Sardine oil triacylglycerols (TAGs).  TAGs were sepd. reversed-phase high performance liquid chromatography (RP-HPLC) with the result of 65 chromatography peaks resolved.  The problem of identification was avoided by the use of two more chromatography techniques.  Sepn. of the sardine oil TAGs into fractions by silver-ion thin layer chromatography (TLC) and its subsequent fatty acid anal. by gas chromatography allowed identification of 59 of the 65 chromatography  peaks.  From those peaks, the major was trimyristin (MMM), with 8.22% of the total.  Dioleoyl-acyl-glycerol (OPO, OOE), dipalmitoyl-acyl-glycerol (PPO, PPPo), dipalmitoleoyl-acyl-glycerol (PoPoO) and dieicosapentaenoyl-acyl-glycerol (EEP) species were found in important amts.
 

Portillo M.P.,  A.I. Tueros, S.J. Perona, V. Ruiz-Gutiérrez, I. Torres and  M.T. Macarulla
Modifications induced by dietary lipid source in adipose tissue  phospholipid fatty acids and   their consequences in lipid mobilization.
British Journal of  Nutrition. 82  (4) (1999)  319-327.
ISSN 0007-1146

Abstract: The aim of the present work was to assess the influence of dietary lipid source on fatty acid phospholipid profiles and on lipid mobilization. Forty male Wistar rats were divided into four groups and fed on high-fat diets which provided olive oil, sunflower oil, palm oil or beef tallow. All rats received the same amount of energy to avoid hyperphagia and differences in energy intake among groups. Phospholipid fatty acids were determined by GC. Lipolysis was stimulated in subcutaneous and perirenal isolated adipocytes by several lipolytic agents, and assessed by the determination of released glycerol. After 4 weeks of feeding, differences in body and adipose tissue weights were not observed. Dietary regimens caused great changes in adipose tissue phospholipid composition: rats fed on palm oil and beef tallow had higher concentrations of saturated fatty acids and animals fed on olive oil or sunflower oil had greater amounts of oleic and linoleic acids, respectively. These modifications did not lead to important changes in adipocyte lipolysis. Significant differences were only observed between palm-oil- and beef-tallow-fed groups when lipolysis was stimulated by isoproterenol in subcutaneous adipocytes. The fact that our feeding protocol did not induce differences in fat accumulation among groups avoids misinterpretations due to adiposity changes. The differences observed between both saturated-fat-fed groups, therefore, should only be attributable to dietary lipids. Despite this effect, the data from this work indicate that some diet-induced changes in adipose tissue fatty acid composition may have little effect on overall function.
 

Prieto González, M.M., J.C. Bada, E. Graciani and I. Lombardía
A comparative study of two heating procedures in the physical refining of edible oils.
Journal of the American Oil Chemists’Society 76 (1999) 1471-1476.
ISSN: 0003-01X

Abstract: Two mixtures of refined sunflower seed oil, one with oleic acid and the other with olive oil distillates from laboratory plant, were physically refined using nitrogen as stripping gas in a discontinuous deodorization pilot-plant scale installation (30-L capacity). Two heating procedures were tested: pun using independent electrical heating for the oil and the gas distillates so as to maintain the same temperature en both,  and anther in which only the oil was heated and controlled, resultanting in a difference in temperatures in the oil an the gas distillates. Two different oil temperatures values and three nitrogen flow rates were also assayed. The statistical technique of blocking with paired comparisons was used to analyze the results. These results showed that maintaining the same temperature in the oil and gas distillates had a positive effect on free fatty acid distillation rate and vaporization efficiency. Oil temperature and nitrogen flow rate also influenced same of the aforementioned responses.
 
 

Puerta de la R.,  V. Ruiz-Gutiérrez  and  J.R.S. Hoult.
Inhibition of leukocyte 5-lipoxygenase  by phenolics from virgin olive oil.
Biochem Pharmacol. 57 (4) (1999) 445?449.
ISSN:  0006-2952

Abstract: Interest in the health-promoting effects of virgin olive oil, an important part of the 'Mediterranean diet', prompted us to determine the anti-eicosanoid and antioxidant effects in leukocytes of the principal phenolic compounds from the 'polar fraction': oleuropein, tyrosol, hydroxytyrosol, and caffeic acid. In intact rat peritoneal leukocytes stimulated with calcium ionophore, all four phenolics inhibited leukotriene B4 generation at the 5-lipoxygenase level with effectiveness hydroxytyrosol > oleuropein > caffeic acid > tyrosol (approximate EC50 values: 15, 80, 200, and 500 microM, respectively). In contrast, none of these compounds caused substantial inhibition of thromboxane generation via the cyclo-oxygenase pathway. Hydroxytyrosol, caffeic acid, oleuropein, and tyrosol (decreasing order of effectiveness) also quenched the chemiluminescence signal due to reactive oxygen species generated by phorbol myristate acetate-stimulated rat leukocytes. None of these compounds were toxic to leukocytes at the concentrations tested. We conclude that the phenolics found in virgin olive oil possess an array of potentially beneficial lipoxygenase-inhibitory, prostaglandin-sparing, and antioxidant properties.
 

Rejano, L.
La Manzanilla fina Sevillana.
Grasas y Aceites 50 (1999) 60-66.
ISSN: 0017-3495.

Resumen: Se describe a la aceituna Manzanilla sevillana como una de las que mejor se ajusta a las características exigibles a una variedad de mesa. Esto ha dado lugar a su expansión por todo el mundo y a una forma de elaboración, denominada estilo sevillano, que también es la más preparada a nivel mundial.A continuación, se describen las líneas de investigación que el Instituto de la Grasa ha desarrollado para la mejora del proceso de elaboración. Finalmente, de destaca la necesidad de mantener y mejorar la calidad de las aceitunas Manzanillas y se describen los últimos métodos objetivos puestos a punto para controlar dicha calidad.
 

Reyes, O.,  E. Sánchez,  N. Rovirosa, R.. Borja, M. Cruz,  M.F. Colmenarejo, R. Escobedo,  M. Ruiz, X.  Rodríguez and O. Correa
Low-strength wastewater treatment by a multistage anaerobic filter packed with waste tyre rubber.
Bioresource Technology  70 (1999) 55-60.
ISSN: 0960-8524.

Abstract: A laboratory-scale fixed bed reactor of five stages running serially, with a free working volume of 6 liters, and  up- and down-flow successively was used for  treating low-strength wastewater. With this design was sought a greater passage of the liquid over the support with biofilm, constituted of waste tyre rubber (disposable material). The objective was to demonstrate the efficiency of this system to purify domestic wastewaters of 1000 mg COD/l of high microbiological load. Different  hydraulic retention times (HRTs), 4, 2 and 1 day, and 12 and 8 hours were studied. For HRTs from 4 to 1 day the efficiency of organic matter removal in the first stage reached the maximum value, and was maintained after passing the liquid through the rest of the stages. For 12 and 8 hours a greater variation of the removal efficiency was observed among all the stages; fundamentally, in the first three. BOD removal efficiencies greater than 60% were achieved: acceptable values for this primary treatment. The variations during  the process in COD,  total and suspended solids, minerals and volatile, volatile fatty acids, alkalinity, ammonia nitrogen and phosphorus, and faecal coliforms were determined. Good results were achieved for short HRTs, therefore, it would be possible to try a greater wastewater flow. The total and faecal coliform removal efficiencies  varied from 99% for four days to  70% for eight hours HRT. This was considered acceptable taking into account the high microorganisms concentration of the wastewater used (1.4•1010 MPN/100 ml).
 

Rodríguez, R., A. Jiménez, R. Guillén, A. Heredia and J. Fernández-Bolaños.
Turnover of white asparagus cell wall polysaccharides during postharvest storage.
Journal of Agricultural and Food Chemistry 47 (1999) 4525-4531.
ISSN:0021-8561

Abstract: The main polysaccharides involved in asparagus cell wall turnover have been identified. Homogalacturonans are lost from both the apical and basal sections of the spear. Galactans are mobilized from the cellulose residue of the apical section and recovered n the KOH-soluble fractions while they are lost from the cellulose residue of the basal section. Xyloglucans are incorporated in the apical region and degraded from the basal one. Cellulose is incorporated in the basal region and lost from the apical one, and acidic xylans are incorporated in high amounts in the basal section of the spear.
 

Rodríguez, R., A. Jiménez, R. Guillén, A. Heredia, J. Fernández-Bolaños.
Postharvest changes in white asparagus cell wall during refrigerated storage.
Journal of Agricultural and Food Chemistry 48 (1999) 3551-3557.
ISSN: 0021-8561

Abstract: The postharvest changes of the white asparagus cell wall have been studied in relation to the toughening process along the length of a spear that was divided into three sections: apical, middle, and basal. Polysaccharides underwent significant turnover during storage. Uronic acid concentration decreased in all sections and in almost all polysaccharide fractions, while neutral sugars increased very slightly in the apical section, decreased in he middle, and increased in the basal one. Xylose, glucose, and galactose are the main neutral sugars implicated in the turnover; xylose accumulated in the hemicellulose fractions of the middle and basal sections, glucose decreased in the hemicellulose and cellulose fractions of the middle section and increased in the cellulose fraction of the basal one, and galactose disappeared mostly from the celluylose fractions of the three sections. Lignin increased most in the middle section and least in the basal one. No increase was detected in the apical one. No important increase of wall phenolics were detected in any part of the spear. The hardening process was limited only to the basal section.
 

Ruiz Gutiérrez V., S.J. Perona, Y.M. Pacheco, J. Villar and F.J.G. Muriana
Incorporation of dietary  tryacilglycerols from  olive  oil and oleic acid-rich sunflower oil into VLDL tryacilglycerols of  hypertensive  patients.
European  Journal of Clinical Nutrition 53 (1999) 687-693.
ISSN: 0954?3007

Abstract: Objectives: To establish whether the ingestion of diets enriched with olive oil or high-oleic sunflower oil may produce changes in the composition of  VLDL  triacylglycerols  from hypertensive patients. It could be relevant for the uptake and metabolism of triacylglycerol-derived  metabolites by  extrahepatic tissues. Design: Patients were assigned to the diets in a random-order sequence. Subjects: The participants were 24 hypertensive patients recruited from a religious community. Interventions: The study was conducted over two four week periods with a four week washout period between both MUFA diets. Results: Dietary olive oil kept in balance the content of saturated fatty acids and decreased the content of arachidonic acid in VLDL triacylglycerols. HOSO diet reduced the content of palmitic acid and increased the content of linoleic acid. There was also a decrease in trioleate-glycerol and an increase in tripalmitate-glycerol of VLDL after the MUFA diets, but these effects were more pronounced in the HOSO group. Intake of olive oil decreased the content of disaturated triacylglycerols and increased the content of dioleate-containing triacylglycerols. A decrease in palmitate-dioleate-glycerol after dietary HOSO was observed. Olive oil (but not HOSO) promoted the presence of long-chain PUFA of n-3 family at the sn-2 position of VLDL triacylglycerols. Conclusions: Our data indicate that olive oil and HOSO, providing a similar concentration of MUFA (oleic acid), differ in the formation of VLDL triacylglycerols in hypertensive patients.
 

Ruíz-Gutierrez V., A. Pérez Espinosa, C.M. Vázquez and C. Santa Maria
Effects  of dietary  fats (fish, olive oil and high-oleic-acid sunflower oil) on  lipid  composition and antioxidant enzymes in rat liver.
British Journal of  Nutrition 82 (3) (1999) 233-241.
ISSN: 0007-1146

Abstract: The effects of two oleic-acid-rich diets (containing olive oil, OO, and high-oleic-acid sunflower oil, HOSO) on plasma and liver lipid composition detoxification enzyme activities, were compared with those of a fish-oil (FO) diet and a control diet. Compared with the control diet, plasma and hepatic total triacylglycerol concentrations were increased in the animals fed on the HOSO and OO diets and decreased in those fed on the FO diet. The animals fed on FO showed the highest level of cholesterol in the liver and had lower plasma cholesterol concentrations when compared with those fed on the two oleic-acid-rich diets. In comparison with the animals fed on the diets enriched in oleic acid, the FO group showed higher hepatic levels of polyunsaturated fatty acids of the n-3 series and lower levels of fatty acids of the n-6 series. Livers of FO-fed rats, compared with those of OO- and HOSO-fed rats showed: (1) significantly higher activities of catalase (EC 1.11.1.6) glutathione peroxidase (EC 1.11.1.9) and Cu/Zn superoxide dismutase (EC 1.15.1.1); (2) no differences in the NADPH-cytochrome c reductase (EC 1.6.99.3) activity. The HOSO diet had a similar effect on liver antioxidant enzyme activities as the OO diet. In conclusion, it appears that changes in the liver fatty acid composition due mainly to n-3 lipids may enhance the efficiency of the antioxidant defence system. The two monounsaturated fatty acids oils studied (OO and HOSO), with the same high content of oleic acid but different contents of natural antioxidants, had similar effects on the antioxidant enzyme activities measured
 
 

Ruiz-Méndez, Mª V. and M.C. Dobarganes
Olive oil and olive pomace oil refining
Oleagineux-Corp Gras-Lipides 6 (1999) 50-54
ISSN: 1258-8210

Abstract: In this paper, refining of olive oil and olive-pomace oil is briefly reviewed. The aspects considered include objectives of the main steps in relation to quality standards and deodorization with nitrogen as a recent technical development.
 

Salas, J.J. and J. Sánchez
Hydroperoxide lyase from olive (Olea europaea) fruits.
Plant Science  143 (1999) 19-26
ISSN 0168-9452

Abstract: Hydroperoxide lyase catalyses the cleavage of hydroperoxides from polyunsaturated fatty acids to yield oxoacids and volatile aldehydes. Some of these aldehydes are constituents of the aroma of many fruits and vegetables and are the major components of the aroma of virgin olive oil. The enzyme has been extracted by solubilization of membrane fractions prepared from the pulp tissues of developing olive fruits. Partial purification by ion-exchange and hydroxylapatite chromatography resulted in the resolution of two isoforms of the enzyme of similar properties: both showed optimal pH at 6.0 and were active with D 13 fatty acid hydroperoxides only. The activity measured with 13-EZZ-hydroperoxy-linolenate was 2.5-fold higher than that measured with 13-EZ-hydroperoxylinoleate. Both enzymes showed high affinity for 13-hydroperoxides, with Km values in the micromolar range. The involvement of this enzyme activity in the formation of volatile aldehydes present in the aroma of olive oil is discussed.

Salas, J.J. and J. Sanchez
The decrease of virgin olive oil flavor produced by high malaxation temperature is due to inactivation of hydroperoxide lyase.
Journal of Agricultural and Food Chemistry  47 (1999) 809-813
ISSN: 0021-8561
 

Salas, J.J., M. Williams., J.L. Harwood and J. Sánchez
Lipoxygenase activity in olive (Olea europaea) fruits.
Journal of the American Oil Chemists’Society 76 (1999) 1163-1168
ISSN: 0003-021X

Abstract: Lipoxygenase activity has been detected in particulate fractions of enzyme extracts from olive pulp submitted to differential centrifugation. The activity in different membrane fractions showed similar properties, with optimal pH in the range of 5.0-5.5 and a clear specificity for linolenic acid, which was oxidized at a rate that was double of that measured with linoleic acid under the same reaction conditions. The enzyme preparations displayed very low activity with dilinoleoyl phosphatidylcholine, suggesting that olive lipoxygenase acts on non-esterified fatty acids. The enzyme showed regiospecificity for the D13-position of both linoleic and linolenic acid, yielding 75-90 % of D13-fatty acid hydroperoxides. Olives showed the highest lipoxygenase activity about 15 weeks after synthesis, with a steady decrease during the developmental and ripening periods. All together, the enzyme displayed properties that support its involvement in the biogenesis of six-carbon volatile aldehydes, which are major constituents of the aroma of virgin olive oil, during the process of oil extraction.
 

Sánchez-Vioque R., A. Clemente, J. Vioque, J. Bautista and F. Millán
Protein isolates from chickpea ( Cicer arietinum L.): Chemical composition, functional properties and protein characterization.
Food Chemistry 64 (1999) 237-243.
ISSN:0308-8146

Abstract: Two types of  protein isolates were prepared from ground chickpea seeds by alkaline extraction, with (Isolate-B) and without (Isolate-A) sodium sulphite, and acid precipitation of the proteins at the isoelectric point (pI 4.3). The percentage of protein recovered from chickpea flour in the preparation of Isolates-A and B were 65.9% and 62.1%, respectively. Chemical composition, main functional properties and protein composition of chickpea flour and protein isolates were determined. Isolates-A and B contained 78.0 and 88.1% of protein, respectively, and had a balanced content of essential amino acids, with respect to the FAO pattern. The in vitro protein digestibility ranged between  95.6 and 96.1%. Isolate-A showed a partial dissociation of the 11S protein because of the high pH used for the protein extraction, and this probably explains the differences observed in the functional characteristics of both isolates

.
Sánchez-Vioque, R., J. Vioque, A. Clemente, J. Pedroche, J. Bautista and F. Millán
Interaction of chickpea (Cicer arietinum L.) legumin with oxidized linoleic acid.
Journal Agricultural Food Chemistry 47 (1999) 813-818.
ISSN: 0021-8561

Abstract: Chickpea legumin has been purified and incubated under oxidizing conditions with linoleic acid to investigate the influence of this acid on the structure and nutritional quality of the protein. At the end of the incubation time, >30% of the linoleic acid was oxidized. The oxidized linoleic acid was highly detrimental to legumin, and the electrophoretic pattern of the protein was completely changed after the incubation period. Nevertheless, neither polymerization nor cleavage of the protein was observed as deduced from gel filtration chromatography, suggesting that the changes observed in native electrophoresis were probably due to oxidation of legumin. The incubation of legumin with linoleic acid also produced a diminution of the contents of methionine and histidine, by 81.3 and 24.3% respectively. Finally, in vitro protein digestibility of chickpea legumin was also seriously affected by the incubation with linoleic acid, decreasing from 84.1 to 69.2%.
 

Sanz, C.,  A.G. Pérez,  R. Olías  and  J.M. Olías
Quality of strawberries packed with perforated polypropylene.
Journal of Food Science  64  (1999) 748-752.
ISSN: 0022-1147

Abstract:  Perforated polypropylene packages were used to study the effects of perforation on gas concentration and strawberry quality.  Strawberry packages with perforations, and treated by simulating transport and shelf-life conditions, developed an internal atmosphere with composition close to that recommended for this fruit.  This controlled decay and reduced deterioration, thus extending strawberry postharvest life.  Moreover, fruit ripeness degree and nutritional value were better preserved, although this MA packaging seemed to reduce fruit color and lead to off-flavor development.
 

Stiefel, P. V. Ruíz-Gutiérrez, E. Gajon, D. Acosta, M.A. García-Donas, J. Villar and J. Carneado
Sodium  transport  kinetic cell membrane lipids  composition, neuronal conduction  and metabolic control in type 1 diabetic patients:changes  after a low   dose n-3 fatty acid dietary intervention.
Annals of Nutrition and Metabolism 43 (2) (1999) 113-120.
ISSN: 0024-3205

Abstract:  Background: A decreased content of n-3 fatty acids in erythrocyte membrane of type 1 diabetic patients, which is inversely related to plasma levels of HbA(1c), has been reported previously. Our aim in this study was to observe the changes after a low-dose n-3 fatty acid (330 mg/day docosahexaenoic acid and 630 mg/day eicosapentanoic acid) dietary intervention in the lipid composition of cell membrane and metabolic control (measured according to plasma HbA(1c) levels). Since changes in both parameters may alter transmembrane sodium transport or influence parameters measuring target organ damage, we also studied the neural conductionquality and activity of four sodium transporters. METHODS: Eighteen type 1 diabetic patients were randomly assigned to continue their usual diet (control group) or to supplement their diet with a daily low dose of n-3 fatty acids (supplemented group). The changes between baseline and end values of the following parameters were compared: HbA(1c), lipid and phospholipid composition of cell membrane, activity of four ion carriers and neural conduction quality. Results: The dietary supplementation caused statistically significant changes in membrane lipid composition, particularly an increase of C22:6 (n-3) and the total n-3 fatty acid (respectively +0.90+/-1.14% vs. -0.44+/-1.23% and +1.36+/-1.62% vs. -0.5+/-1.80%, p<0.05). After the dietary supplementation, we also observed a significant decrease of HbA(1c) (-2.00+/-1.9% vs. -0.13+/-0.48%, p<0.05), without significant changes in the dose of insulin required, an increase in the motor conduction velocity by the median nerve (+2.12 +/-1.35 m/s vs. -0.8+/-2.34 m/s, p<0.05) and a decrease of the V(max) of the Na(+)-Li(+) countertransport (-96.6+/-111.2 vs. +58.1+/-81.3 micromol/l cell/h(-1), p<0.01).  Conclusion: A low-dose omega-3 fatty acid dietary supplementation may change the fatty acid composition of the cell membrane and improve the metabolic control of diabetes. Using this dose, we also observed a decrease of the maximal rate of Na(+)-Li(+) countertransport and a slight improvement of neural conduction.
 
 

Travieso, L.,  R.O. Cañizares,  R. Borja,  F. Benítez,  A.R. Dominguez, R. Dupeirón and V. Valiente
Heavy metal removal by microalgae.
Bulletin of Environmental Contamination and Toxicology  62 (2) (1999) 144-151.
ISSN:  0007-4861

Abstract:  The effect of the heavy metals Cd, Zn and Cr on the microalgae growth in the biological wastewater treatment was studied using the microalgae free cell´s suspended culture Scenedesmus acutus and Chlorella vulgaris.  The immobilization of microalgae cells using kappa-carrageenan and polyurethane foam as supports for heavy metals removal was also investigated.  In the free cell´s system, it was found that Chlorella vulgaris support Zn concentrations £ 600 mg/l, but some morphological variations were detected in the cells. For concentrations of 100-400 mg/l no variations occurred. Scenedesmus acutus resists Zn concentrations of 100 mg/l max., and cellular d. diminishes when the Zn concentration increases. Both strains presented morphological problems at Cd concentrations > 2 mg/l. The Maximum Cr concentrations for Scenedesmus acutus and  Chlorella vulgaris were 15 and 45 mg/l, respectively. In the immobilized experiments, the packed columns, for both strains, had more efficient behavior than fluidized columns. Kappa-carrageenan revealed higher metal uptake compared with the polyurethane columns.  Scenedesmus acutus showed better metal removal efficiencies than Chorella vulgaris. Both microalgae immobilized on both supports, are tolerant to heavy metals concentrations over the normal concentrations of these ions in industrial wastewaters.
 

Turnheim K., J. Gruber, C. Wacher and V.  Ruiz Gutiérrez
Membrane phoholipid  composition affects function of potasium chanels from rabbit colon epitelium.
American Journal of  Physiology  277 (Cell Physiology 46) (1999) 83-90.
ISSN 0002-9513

Abstract: We tested the effects of membrane phospholipids on the function of high-conductance, Ca(2+)-activated K(+) channels from the basolateral cell membrane of rabbit distal colon epithelium by reconstituting these channels into planar bilayers consisting of different 1:1 mixtures of phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylinositol (PI). At low ambient K(+) concentrations single-channel conductance is higher in PE/PS and PE/PI bilayers than in PE/PC bilayers. At high K(+) concentrations this difference in channel conductance is abolished. Introducing the negatively charged SDS into m PE/PC bilayers increases channel conductance, whereas the positively charged dodecyltrimethylammonium has the opposite effect. All these findings are consistent with modulation of channel current by the charge of the lipid membrane surrounding the channel. But the K(+) that permeates the channel senses only a small fraction of the full membrane surface potential of the charged phospholipid bilayers, equivalent to separation of the conduction pathway from the charged phospholipid head groups by 20 A. This distance appears to insulate the channel entrance from the bilayer surface potential, suggesting large dimensions of the channel-forming protein. In addition, in PE/PC and PE/PI bilayers, but not in PE/PS bilayers, the open-state probability of the channel decreases with time ("channel rundown"), indicating that phospholipid properties other than surface charge are required to maintain channel fluctuations.
 

Valdenebro, M.S., M. León Camacho,  F. Pablos,  A.G. González,  and M.J. Martín
Analysis of  the varietal  composition of  roasted coffee according to their sterolic  contentby using principal component regression.
Analyst 124 (1999) 999-1002
ISSN: 0003-2654

Abstract: A method to determine the percentage of the arabica coffee in mixtures of roasted coffee is proposed. The sterol content of roasted coffee blends was determined by extracting the coffee oil, saponifying the lipids and the sterols present in the unsaponifiable fraction were separated by thin layer chromatography. Then, they were converted into trimethyl silyl derivatives and analysed by gas chromatography. Twelve sterols were determined in roasted coffee samples that were mixtures of the arabica and robusta classes. Considering the sterols as chemical descriptors, Principal Component Regression was applied. D5avenasterol was found to be a very adequate variable to establish the arabica percentage in roasted coffee blends. The method was applied to determine the arabica/robusta composition of commercial roasted coffee samples.
 
 

Vázquez, C.M., M.R. López, L. Bravo and  V. Ruíz Gutiérrez
Comparation of effects of  two different monounsaturated oils on the biliary secretion in  rats.
Nutrition Research  19 (1999) 1097?1112.
ISSN: 0271-5317

Abstract: Effects of two oils, both with the same high content of monounsaturated fatty acids (MUFAs), 80.28% for olive oil (OO) vs. 80.54% for high-oleic sunflower oil (HOSO), on biliary bile acid and lipid secretion have been studied in rats.  There was a gradual increase in bile flow, concn. and output of bile acids during the administration of the oils, the increase being higher in HOSO-fed animals.  The component of the biliary bile acids showed a decrease in the percentage of chenodeoxycholic acid, accompanied by an increase in the level of muricholic acid after the administration of two oils when compared to control group.  There was no difference in the percentage of cholic acid and deoxycholic acid among exptl. groups.  Biliary phospholipid levels were not modified in any groups.  Biliary cholesterol content was decreased at 3 and 5 days in OO-fed animals when compared with the other exptl. groups.  Consequently, the ratio phospholipid/free cholesterol was enhanced in these animals.  There were no statistically significant differences in the individual phospholipid among the exptl. groups.  The major phospholipid in the bile was phosphatidylcholine.  The fatty acid compn. of biliary lipids was lightly modified similar to the major fatty acid compn. in the oils.  These results showed a decrease in biliary cholesterol content after OO administration compared to other exptl. groups, and suggest that the MUFAs are not solely responsible for the biliary cholesterol-lowering effect.  There was no a relationship between biliary lipid and bile acid secretion after the administration of oils.
 

Villanueva Suárez, M. J., A. Redondo Cuenca, M.D. Rodríguez Sevilla and A. Heredia Moreno.
Postharvest storage of white asparagus (Asparagus officinalis L.): Changes in dietary fibre (non-starch polysaccharides).
Journal of Agricultural and Food Chemistry 48 (1999) 3832-3836.
ISSN: 0021-8561

Abstract: Changes occurring in the content and composition of dietary fiber of white asparagus during storage in different conditions were studied (2ºC; 2ºC in polyethylene bags with air; 2ºC in polyethylene bags with a selected gas mixture). The neutral sugars and uronic acid composition of dietary fiber was determined by gas chromatography and by a spectrophotometric method. The modifications observed in dietary fiber of the asparagus stored at 2ºC were more rapid and pronounced than those in polyethylene bags. The most important changes corresponded to xylose and glucose from insoluble dietary fiber and galactose from soluble dietary fiber. Statistical analysis indicated that the modifications were significantly affected by the type of storage and time.
 

Villanueva, A., J. Vioque,  R. Sánchez-Vioque, A. Clemente, J. Pedroche, J. Bautista and F. Millán.
Peptide characteristics of sunflower protein hydrolysates.
Journal of the American Oil Chemists’Society 76 (1999) 1455-1460.
ISSN: 0003-021X

Abstract: Sunflower protein isolate was used as the starting material for preparation of an extensively hydrolyzed peptide product. Protein was hydrolyzed using an endopeptidase (Alcalase), an exopeptidase (Flavourzyme) or both enzymes sequentially. Combined use of these proteases generated the highest degree of hydrolysis, 54.2%, and highest solubility, around 90%, between pH 2.5 and 7. Molecular weight profiles of the hydrolysates were characterized by gel filtration chromatography and denaturing electrophoresis. Amino acid compositions and solubilities of the different hydrolysates also were studied.
 

Villanueva, A., R. Sánchez-Vioque, A. Clemente, J. Vioque, J. Bautista  and F. Millán
Obtention of enzymatic sunflower protein hydrolysates using sequentially an endo- and an endo/exo-peptidase.
Grasas y Aceites 50 (1999) 472-476.
ISSN: 0017-3495

Abstract: A high quality protein isolate has been obtained from defatted sunflower meal by alkaline extraction and isoelectric precipitation. Protein content was increased from 31.2% in the defatted flour to 97% in the protein isolate. The percentages of fibre, soluble sugars, polyphenols and residual lipids in the protein isolate were reduced in more than 90% with respect to the defatted meal. The protein isolate was used as starting material for the generation of an extensive enzymatic protein hydrolysate. The hydrolysis was carried out in a pH stat using sequentially an endo-peptidase (alcalase) and an endo/exo-peptidase (flavourzyme). The protein hydrolysate had a 50.7% degree of hydrolysis, was white and non bitter.
 

Vioque, J., R. Sánchez-Vioque, A. Clemente, J. Pedroche, J. Bautista and F. Millán
Production and characterization of enzymatic rapeseed protein hydrolysates.
Journal of the American Oil Chemists’Society  76  (1999) 819-823.
ISSN: 0003-021X

Abstract: Rapeseed protein isolate has been used as starting material for the generation of extensive protein hydrolysates. Protein hydrolysis was achieved by using sequentially alcalase (endo-peptidase) and flavourzyme (endo/exo-peptidase). The final hydrolysate had a 61.4% degree of hydrolysis and was completely soluble between pHs 2.5 and 7. Molecular weight profiles of the protein hydrolysates were characterized by gel filtration chromatography. During the hydrolysis a reduction in the protein size was observed with generation of small peptides and free aminoacids. Amino acid composition in fractions of different molecular weight of the final hydrolysate was analyzed. Some of these fractions, with differential aminoacid composition, could be useful for food suplementation or treatment of determined clinical syndromes.

Vioque, J., R. Sánchez-Vioque, A. Clemente, J. Pedroche, J. Bautista and F. Millán
Purification and partial characterization of chickpea 2s albumin.
Journal of Agricultural Food Chemistry 47 (1999) 1405-1409.
ISSN: 0021-8561

Abstract: A chickpea 2S albumin has been purified by solubilization in 60% methanol and ion-exchange chromatography. Under denaturing conditions it is composed of two peptides of 10 and 12 kDa. Native molecular mass determined by gel filtration chromatography is of 20 kDa. Amino acid composition shows that it is rich in sulphur amino acids, mainly cysteine with 4.6% of the total. On the other hand it has antinutritional characteristics of being allergenic for chickpea sensitive individuals and inhibitory against porcine chymotrypsin with a lesser degree toward trypsin. The interest of the results from a nutritional point of view are discussed.
 

Zamora, R., M. Alaiz and F. J. Hidalgo
Determination of e-N-pyrrolylnorleucine in fresh food products
Journal of Agricultural and Food Chemistry 47 (1999) 1942-1947.
ISSN: 0021-8561

Abstract: e-N-Pyrrolylnorleucine was determined in different fresh food products to study its presence as a normal component of food proteins. Twenty-two different products were screened: cod, cuttlefish, salmon, sardine, trout, beef, chicken, pork, broad bean, broccoli, chickpea, garlic, green pea, lentil, mushroom, soybean, spinach, sunflower, almond, hazelnut, peanut, and walnut. Foods were homogenized, their proteins precipitated with trichloroacetic acid and hydrolyzed with 2 N NaOH for 20 h, and the e-N-pyrrolylnorleucine content was determined by capillary electrophoresis. The e-N-pyrrolylnorleucine, which was identified by HPLC/MS in sardine muscle hydrolysate, ranged in the twenty-two foods analyzed from 0.24 to 6.36 mmol/g. This concentration was correlated with the protein content of the food (r = 0.687, p = 0.00041). In addition, the e-N-pyrrolylnorleucine/lysine ratio was found to be a function of the lipid, iron, and protein contents of the food (r = 0.881, p < 0.0001) and was directly correlated with lipid and iron contents and inversely correlated with the protein content. These results are in agreement with the oxidative stress origin proposed for e-N-pyrrolylnorleucine, and suggest that the e-N-pyrrolylnorleucine/lysine ratio is a characteristic of each food. In addition, e-N-pyrrolylnorleucine seemed to be a normal component of many fresh food products, in which it may be acting as natural antioxidant.

Zamora, R., M. Alaiz and F. J. Hidalgo
Modification of histidine residues by 4,5-epoxy-2-alkenals
Chemical Research in Toxicology 12 (1999) 654-660.
ISSN: 0893-228X

Abstract: The reactions of 4,5(E)-epoxy-2(E)-heptenal with 4-methylimidazole and Na-acetyl-L-histidine methyl ester were studied to characterize the adducts produced in the modification of histidine residues by epoxyalkenals and to develop a methodology for the determination of these adducts in protein hydrolysates. The reaction products, which were isolated and characterized, resulted in the Michael adducts produced in the addition of one of the imidazolic nitrogens to the carbon-carbon double bond of the epoxyalkenal. Only some of the theoretical isomers were produced. Thus, in the reaction with 4-methylimidazole the main product was 4,5-epoxy-3-[4-methylimidazol-1-yl]-heptanol (88 %), although the formation of 4,5-epoxy-3-[5-methylimidazol-1-yl]-heptanol (12 %) was also observed. On the other hand, the reaction with Na-acetyl-L-histidine methyl ester produced exclusively Na-acetyl-1-[1’-(1”,2”-epoxybutyl)-3’-hydroxypropyl]-L-histidine methyl ester. This last compound was used to develop a procedure for the determination of 4,5(E)-epoxy-2(E)-heptenal/histidine adducts in protein hydrolyzates. When this procedure was applied to the analysis of bovine serum albumin treated with 0.01-10 mM 4,5(E)-epoxy-2(E)-heptenal, the formation of the adduct was observed and its concentration increased with the concentration of the aldehyde and the incubation time, and was parallel to the histidine losses observed in the protein after acid hydrolysis as well as to the formation of protein carbonyls. In addition, the number of histidine residues lost in the protein was very similar to the number of adduct residues produced, suggesting that the addition reaction is the major mechanism for histidine losses suffered by proteins following their reaction with epoxyalkenals.