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ABSTRACT: There were no temperature- or time-dependent significant changes in colour or iron content of two cultivars of bottled ripe olives during heat sterilization at temperatures between 117 and 129°C. the addition of calcium had no effect on the activation parameters of texture, although the olives were always firmer when the cation was added. the z-values for the texture of ripe olives were found to be around 20°C and the average activation energy was 138 kJ/mol.
International Journal of Food Science & Technology 06/2007; 30(1):31 - 36. · 1.26 Impact Factor
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ABSTRACT: The fatty acid composition of 67 commercial presentations of table olives was determined. The most abundant fatty acids, in decreasing order of presence, were C18:1, C16:0, C18:2 n-6, and C18:0. The ranges, expressed as grams of fatty acids per 100 g of edible portion, for the different nutritional fractions were as follows: saturated fatty acids, 2.07-5.99; monounsaturated fatty acids, 5.67-19.42; polyunsaturated fatty acids, 0.52-3.87; and trans-fatty acids, 0.08-0.44. Principal component analysis of the matrix of the fatty acid composition led to the deduction of new factors. The first accounted for 55.10% of the total variance and was mainly related to C16:10, C18:0, C20:0, C22:0, C24:0, C18:1, C18:1t, and C20:1. The second factor accounted for 10.33% of variance and was related to C16:1 and C18:2 n-6. They did not permit differentiation among elaboration types or cultivars. However, discriminant analysis was successfully applied for this objective. The fatty acids that most contributed to discriminate among elaboration styles were C17:1, C18:1, C16:0, C17:0, and C18:0 (function 1) and C17:0, C17:1, C20:0, C16:0, C18:1, and C24:0 (function 2). In the case of cultivars, they were C20:0, C18:1, C17:1, C18:2 n-6, C18:1t, and C18:2t (function 1); C18:2 n-6, C18:1, C16:0, C20:0, C18:0, and C18:2t (function 2); and C17:0, C18:3 n-3, and C17:1 (function 3). Results from this study have shown differences among the fatty acid composition and fat content of the diverse commercial presentations of table olives, which can be applied in predictive and classification discriminant analysis.
Journal of Agricultural and Food Chemistry 10/2006; 54(18):6747-53. · 2.82 Impact Factor
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ABSTRACT: The effects of the pH in the flesh of ripe olives processed for table olive production, the type of acid used to correct it, the heating process used and the iron content of the flesh on the colour of the final product were studied. The best colour was obtained by bottling the fruits at pH 7. Additions of acids, especially citric acid, always caused discoloration when olives were bottled at a pH of around 7. On the other hand, when the fruits were packed at a pH higher than 7 the addition of certain amounts of acids produced darker olives. Darker colours are related to higher iron contents in the flesh, but treatment of olives with ferrous gluconate before neutralising the pH of the flesh yielded better colours than those treated after neutralising for the same iron concentration in the olives. Results obtained after adding iron to the oxidation solutions did not show the same pattern as those obtained using fruits. These results suggest that the fixation of the colour formed is not only due to the phenol-iron complexes.
Journal of the Science of Food and Agriculture 09/2006; 67(1):35 - 41. · 1.44 Impact Factor
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ABSTRACT: The kinetics of the oxidation process to produce ripe olives were studied. The sodium hydroxide solutions used for treating the ripe olives contain the same polyphenols as the olives treated with these solutions. These liquids could be utilized as model systems to study the oxidation reactions of polyphenols. However, oxidation of the olive surface was remarkably slower because the diffusion rate of oxygen into the flesh of the fruit was very low. Oxidation of the polyphenols (hydroxytyrosol and caffeic acid) in the sodium hydroxide solutions followed first-order kinetics. The values of the constant for hydroxytyrosol were higher than those for caffeic acid and darkening of the liquids. Olive and solution colour were darker and oxidation rates increased with increasing pH.
Journal of the Science of Food and Agriculture 09/2006; 60(3):327 - 331. · 1.44 Impact Factor
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ABSTRACT: A survey of vitamin E levels in a wide variety of olive-based foodstuffs was conducted. Vitamin E was determined by normal-phase
HPLC. The only form of vitamin E found in all commercial presentations of table olives was α-tocopherol, with an average content
of 3.1 mg/100 g edible portion. A very low content (<0.4 mg/100 g edible portion) of γ-tocopherol was found in most of the
samples analyzed. The main sources of variation of vitamin E were olive cultivars and commercial presentations. Processing
type (Spanish style green olives, directly brined olives, ripe olives) had a limited influence. Irrespective of the elaboration
style, the Gordal cultivar was the poorest with respect to the vitamin E content. On the other hand, all commercial presentations
based on the Hojiblanca cultivar had high contents of vitamin E. The results of this study may be used by the industry for
requirements of nutritional labeling or by nutritionists to estimate vitamin E intakes in diets that include table olives.
Journal of Oil & Fat Industries 01/2005; 82(2):129-133. · 1.77 Impact Factor
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ABSTRACT: The concentration of provitamin A carotenoids in table olives was determined. Only -carotene was found in all commercial presentations. -carotene was also present in final products containing carrots. Concentrations of -carotene, referring to 100g edible portion, ranged from an average of 197 to 1,387g in green olives, from 37 to 726g in directly brined olives and from 39 to 333 in ripe (darkened by oxidation) olives. Thus, some commercial presentations of table olives can be considered reasonable sources of provitamin A. Several groups were formed within elaboration styles and cultivars, according to commercial presentations. Their averages and other statistical estimations are also given. These results may be used by the industry as a source of information for nutritional labelling or by nutritionists to estimate provitamin A intakes in diets that include table olives.
European Food Research and Technology 01/2005; 221(3):406-411. · 1.57 Impact Factor
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ABSTRACT: The distribution of sorbic and benzoic acids in the different phases of table olives was studied. To a large extent, these preservatives accumulated in the oil phase of fruits stored in acid conditions, as well as in juice and other tissue components. Thus, around 20–30% of the benzoic acid in olives was found in the juice phase, 30–50% in the oil phase and 30–40% in the rest of the olive flesh. Experiments carried out with black ripe olives revealed that an increase in pH of the medium gave rise to a decrease in the absorption phenomenon in whole olives and in the oil phase. As a consequence of this effect, benzoic acid could be leached from stored black ripe olives during the darkening process, although the calcium content of fruits greatly influenced the diffusion phenomenon. The results obtained in this study are important for future legal limitations of these preservatives in table olives and inhibition capacity of them in commercial table olives.
European Food Research and Technology 05/2004; 219(1):75-79. · 1.57 Impact Factor
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ABSTRACT: The individual evolution of phenolic compounds has been studied during the natural fermentation of black olives for the first time. Cyanidin 3-rutinoside and cyanidin 3-glucoside were the main anthocyanins identified in fresh olives, and they were not detected after 1 month of storage either in brine or in olive. The fruit colors were different when aerobic or anaerobic conditions were used and as a consequence of the different anthocyanin polymerizations that took place. At time zero, the polyphenols observed in the olive juice were hydroxytyrosol-4-beta-glucoside, oleuropein, hydroxytyrosol, tyrosol, salidroside, and verbascoside and, after 12 months, the main phenol was hydroxytyrosol. The polyphenol content in the oil phase of olives was also analyzed. The dialdehydic form of elenolic acid linked to hydroxytyrosol and tyrosol, oleuropein aglycon, and ligstroside aglycon were the main compounds found at the beginning of fermentation but were not detected after 3 months. In contrast, hydroxytyrosol, hydroxytyrosol acetate, tyrosol, and tyrosol acetate were the main polyphenols detected in the oil phase of the final product. The acid hydrolysis of the initial glucosides (in olive juice) and the aglycons (in oil phase) was, therefore, the main reaction that took place during fermentation.
Journal of Agricultural and Food Chemistry 05/2004; 52(7):1973-9. · 2.82 Impact Factor
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ABSTRACT: Polyphenols were determined by HPLC in the juice and oil of packed table olives. The phenolic compositions of the two phases were very different, hydroxytyrosol and tyrosol being the main polyphenols in olive juice and tyrosol acetate, hydroxtyrosol acetate, hydroxytyrosol, tyrosol, and lignans (1-acetoxypinoresinol and pinoresinol) in oil. The type of processing had a marked influence on the concentration of polyphenols in olive juice and little on the content in oil. The analyses carried out on 48 samples showed that turning color olives in brine had the highest concentration in polyphenols ( approximately 1200 mg/kg), whereas oxidized olives had the lowest ( approximately 200 mg/kg). Among olive cultivars, Manzanilla had a higher concentration than Hojiblanca and Gordal. The type of olive presentation also influenced the concentration of polyphenols in olives, decreasing in the order plain > pitted > stuffed. The results obtained in this work indicate that table olives can be considered a good source of phenolic antioxidants, although their concentration depends on olive cultivar and processing method.
Journal of Agricultural and Food Chemistry 02/2004; 52(3):479-84. · 2.82 Impact Factor
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ABSTRACT: There is increasing interest in olive phenolic compounds because of their biological properties as well as their contribution to the colour, taste and shelf life of olive products. Phenolic compounds in natural black Spanish olives are characterised by HPLC-UV and HPLC-MS. Hydroxytyrosol-4-#-D-glucoside has been identified as the major phenolic compound in natural black olives. A qualitative and quantitative study of phenolic substances such as hydroxytyrosol, salidroside, tyrosol, verbascoside, luteolin-7-glucoside, rutin, demethyloleuropein and oleuropein has been carried out. Traces of other phenolic compounds such as catechol, vanillic acid, apigenin-7-rutinoside and ligustroside have also been found by mass spectroscopy. Secoiridoid aglycons, the main phenolic compounds in olive oil, were not detected in olive flesh except the dialdehydic form of elenolic acid linked to hydroxytyrosol (HyEDA), particularly in the Arbequina olive variety and only traces were detected in other varieties. Among anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside were the only anthocyanin compounds detected in all the varieties studied. The UV and MS spectra of several unknown phenolic compounds have also been described.
European Food Research and Technology 11/2002; 215(6):489-496. · 1.57 Impact Factor
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ABSTRACT: Monovarietal Picual olive oils possibly represent 25% of the world's olive oil production. HPLC was used to analyse phenolic compounds and tocopherols in Picual olive oils obtained during two successive crop seasons (1999/2000 and 2000/2001) and from different geographic areas of the Jan province, which is located in the south of Spain. Oils obtained at the beginning of each season had a higher content of each phenolic compound than those obtained at the end, although this effect was more pronounced for orthodiphenols than for non-orthodiphenols. The main phenolic compound detected in this monovarietal oil was the aglycon of oleuropein followed by the other secoiridoid aglycons. Lignan concentration in oil showed low variability with season and harvesting time, and pinoresinol in particular was present at a concentration of about 40 ppm. Therefore, the total polyphenol content of this monovarietal oil ranged from 300 to 700 ppm. Similarly, significant differences in these compounds were not detected between geographic areas. This monovarietal oil is very stable due to its high content of oleic acid and for this reason, the storage of oils for 2 years in amber glass bottles caused only a 30% decrease in phenolic compounds. An increase was found in simple phenols such as hydroxytyrosol and tyrosol liberated from the acid hydrolysis of the secoiridoid aglycons, and minor losses in tocopherols were also observed. These data provide a basis for the evaluation of polyphenol intake from virgin olive oil consumption, particularly from the monovarietal olive oil most consumed in the world.
European Food Research and Technology 10/2002; 215(5):407-412. · 1.57 Impact Factor
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ABSTRACT: There is increasing interest in olive polyphenols because of their biological properties as well as their contribution to the color, taste, and shelf life of olive products. However, some of these compounds remain unidentified. It has been shown that hydroxytyrosol 4-beta-D-glucoside (4-beta-D-glucosyl-3-hydroxyphenylethanol) coeluted with hydroxytyrosol [(3,4-dihydroxyphenyl)ethanol] under reversed phase conditions in the phenolic chromatograms of olive pulp, vegetation water, and pomace of olive oil processing. A method to separate this compound from hydroxytyrosol by HPLC has been developed. The concentration of this glucoside increased in olive pulp with maturation and could be the main phenolic compound in mature olives. In contrast, the presence of this compound was not detected in olive oil by using HPLC-MS. The compound must be considered both in table olives and olive oil processing because of its glucose and hydroxytyrosol contribution to these products.
Journal of Agricultural and Food Chemistry 07/2002; 50(13):3835-9. · 2.82 Impact Factor
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ABSTRACT: There is no generally accepted method for determination of the amounts of iron and manganese in table olives. Application of flame atomic absorption spectrometry to the analysis of both elements has been examined to validate a method that may be used by the industry's quality control laboratory as well as by the laboratories of regulatory agencies. The method has detection limits of 0.106 and 0.022 mg/L and quantification limits of 0.271 and 0.057 mg/L, for Fe and Mn, respectively, referred to the solution to be measured. There was no significant effect due to the matrix, but a slight bias due to the presence of Ca has been detected. Recoveries were excellent, and the method was robust. Influence of operator, HCl and Mg salt compounds, calcination equipment, or dates on results was not found. Relative errors were, in general, below 4% for both cations, and repeatability was below 3.43 and 0.38 mg/kg of olive paste for Fe and Mn, respectively. The method is proposed for the analysis of Fe and Mn in ripe olives and table olives in general.
Journal of Agricultural and Food Chemistry 07/2002; 50(13):3654-9. · 2.82 Impact Factor
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ABSTRACT: A detailed study has been made of the colour fixation stage of ripe olive processing. The effects of the degree of iron oxidation and the colour-fixing liquid on iron availability have been investigated and an explanation is given for the greater effectiveness of ferrous salts compared to ferric salts. Likewise, a 24 factorial design was used to study the influence on olive colour of the pH of the aeration solution, the type of colour-fixing liquid, the type of ferrous salt and the aeration system. The data were analysed by multivariate and univariate analysis of variance (MANOVA/ANOVA), the best results being obtained with low pH (4.0), tap water, ferrous lactate and no aeration during the first 3 h of immersion in the colour-fixing solution. These results can be explained by the iron availability averages having been altered by differences in the concentration of organic matter, the pH of the solution and the diffusion of iron into the olive flesh. The results can be used to reduce iron residues in ripe olives.© 2001 Society of Chemical Industry
Journal of the Science of Food and Agriculture 09/2001; 81(14):1364 - 1370. · 1.44 Impact Factor
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ABSTRACT: Phenolic compounds are of fundamental importance to the quality and nutritional properties of virgin olive oils. In this paper,
the high-performance liquid chromatographic analysis of simple and complex olive oil phenols in the streams generated in the
two-phase extraction system was carried out using Arbequina and Picual olives. The malaxation stage reduced the concentration
of orthodiphenols in oil ca 50–70%, while the concentration of the nonorthodiphenols remained constant, particularly the recently identified lignans
1-acetoxypinoresinol and pinoresinol. Oxidation of orthodiphenols at laboratory scale was avoided by malaxing the paste under
a nitrogen atmosphere. Phenolic compounds in the wash water used in the vertical centrifuge were also identified. Hydroxytyrosol,
tyrosol, the dialdehydic form of elenolic acid linked to hydroxytyrosol were the most representative phenols in these waters.
Hence, phenolic compounds in the wash waters came from both the aqueous and the lipid phases of the decanter oily must.
Journal of Oil & Fat Industries 05/2001; 78(6):625-629. · 1.77 Impact Factor
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ABSTRACT: Polyphenols of olive oil show autoprotective, sensory, and nutritional-therapeutic effects. Two new phenolic compounds have
been isolated from virgin olive oils by preparative high-performance liquid chromatography and their structures established
on the basis of their mass spectra and nuclear magnetic resonance spectral data. The compounds identified are the lignans
pinoresinol and 1-acetoxypinoresinol. Both have been found in all the commercial virgin olive oils analyzed. Pinoresinol concentration
was rather similar in all the oils. In contrast, 1-acetoxypinoresinol concentration was higher in oils of the Arbequina and
Empeltre cultivars than in Picual or Picudo cultivars. Pinoresinol and 1-acetoxypinoresinol may represent the major phenolic
compounds in some Arbequina and Empeltre oils. Lignans possess biological and pharmacological properties and, therefore, the
two new compounds identified in olive oils may contribute to the reported beneficial effects which are attributed to polyphenols
on human health of a diet rich in olive oil.
Journal of Oil & Fat Industries 06/2000; 77(7):715-720. · 1.77 Impact Factor
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ABSTRACT: No purification procedure exists for treating the waste waters from the Spanish-style green olive industry. This study shows that an activated sludge process can be used successfully, yielding a 75–85% COD reduction, due mainly to the removal of organic acids and ethanol present in the waste. In contrast, only a small proportion of polyphenols was consumed. These residual polyphenols can account for most of the remaining COD and the residual brown colour. Grau's model for substrate removal rate was applied to take account of the effect of influent-substrate concentration on the effluent COD concentration. The constant value with this model (k) was 9.8 day−1. Likewise, increasing the hydraulic retention time and temperature improved the sludge removal. Thus, a COD of 200–300 mg dm−3 in the effluent was routinely achieved. Concentrations of NaCl up to 3% did not affect the aerobic system although the sludge volume index was higher than 200 cm3 g−1.© 2000 Society of Chemical Industry
Journal of Chemical Technology & Biotechnology 06/2000; 75(6):459 - 463. · 2.17 Impact Factor
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ABSTRACT: The catalytic effect of different metal cations on the chemical oxidation of caffeic acid and hydroxytyrosol in model systems and at pH 7 and 30 °C was studied. The effect of the metals on the rate of consumption of the o-diphenols was in the order Co > Mn > Zn > Fe > Ca, Cu, Mg, Al. When the reactions were carried out in the presence of manganese, the consumption of o-diphenols and oxygen increased and darker solutions were obtained than in the absence of the cation. An increase in the rate of oxygen consumption by manganese in solution was also observed. The oxygen uptake after 100 h of reaction was around 2.0−2.5 mol/mol of o-diphenol when manganese was added and 1.5−1.8 mol if the cation was absent. These findings suggest that Mn could be used to catalyze the oxidation of olive o-diphenols during ripe olive processing. Keywords: Olive; o-diphenols; oxidation; metals
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ABSTRACT: Restrictions on the discharge of chloride in wastewater streams have recently increased, and processors of black ripe olives have to look for alternative storage systems to the traditional brines. Ripe olives of the Hojiblanca variety were stored under aerobic and anaerobic conditions in industrial underground tanks for one year. The aerobic systems assayed with or without NaCl produced a continuous consumption of sugars as they diffused from the fruits to the surrounding liquid. At the same time sugars accumulated in the liquid for months when anaerobic conditions were employed and a high concentration of acetic acid was used. In the end, glucose was consumed with time as well and, in addition to yeasts, acetic acid and lactic acid bacteria grew in the cover solutions. The assessment of olives stored under the different systems and processed as black ripe olives revealed that the traditional aerobic brines gave rise to darker and firmer fruits. However, olive industries must eliminate chlorides from their waste streams. Promising new storage systems were (i) anaerobic preservation of olives in water with an initially high concentration of acetic acid, and (ii) aerobic preservation in water with an initially low concentration of acetic acid. Both systems produced a good quality product, free of microbial spoilage and organoleptic defects.
Journal of Food Engineering. 80(4):1206-1212.
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ABSTRACT: The use of Mn to improve the darkening process of ripe olives was studied with Manzanilla, Hojiblanca, Carrasqueña and Cacereña cultivars on both pilot and industrial scales during the “desalting” and storage steps. Results showed a general improvement of colour when Mn was used, although it was limited in the case of the Cacereña cv. Its addition to the storage brine for a period of at least 1 month yielded the best darkened olives and gave rise to low residues of Mn (around 10 mg/kg) in the final product, these conditions of processing being the most recommendable. This work has scaled up to use Mn during the oxidation process of ripe olives from pilot to industrial scale.
Journal of Food Engineering.
