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Aranzazu García M Victoria Ruiz-Méndez Concepción Romero Manuel Brenes 《Journal of the American Oil Chemists' Society》2006,83(2):159-164
By definition, virgin olive oil is consumed unrefined, although a great proportion of the olive oil produced has to be refined
to render it edible. Phenolic compounds are among the substances eliminated during the refining process; in the present work
these were characterized by HPLC, and their evolution during the different refining steps was studied. The complete refining
process removed most polyphenols from oils, but the behavior of individual compounds at each step also was observed. o-Diphenols
(hydroxytyrosol, catechol, and hydroxytyrosol acetate) and flavonoids (luteolin and apigenin) were eliminated first during
the alkaline treatment. Tyrosol and 4-ethylphenol remained in the oil until the deodorization step. A large amount of phenolic
compounds was discovered in the refining by-products such as soapstocks and deodorization distillates. In the latter streams,
the concentrations of tyrosol and 4-ethylphenol reached up to 149 and 3720 mg/kg by-product, respectively. This high level
of 4-ethylphenol and its well-known strong off-odor can interfere during further processing of the deodorization distillates,
and this must be taken into account when deciding what is to become of them. Similarly, the results of this work open the
possibility of recovering phenolic compounds from the “second centrifugation olive oils” by adding a new washing step prior
to the refining process. By including this new step, the most polar polyphenols, hydroxytyrosol and tyrosol, will diffuse
from oil to water and a concentration of up to 1400 mg/L of hydroxytyrosol may be achieved. 相似文献
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Inés González‐Hidalgo Sancho Bañón José María Ros 《International Journal of Food Science & Technology》2012,47(4):674-681
The main by‐product from the table olive canning industry is the stone with some residual olive flesh. The purpose of this study was to evaluate the composition – phenolic compounds (hydroxytyrosol, tyrosol and oleuropein) and tocopherol – and the antioxidant activity in different fractions (flesh, stone and seed) from the table olive by‐product and the whole by‐product. The highest amounts of phenolic compounds (1710.0 ± 33.8 mg kg?1) as well as the highest antioxidant activity (8226.9 ± 9.9 hydroxytyrosol equivalents mg kg?1) were obtained in the seed. The highest amounts of hydroxytyrosol (854.8 ± 66.0 mg kg?1) and tyrosol (423.6 ± 56.9 mg kg?1) were found in the whole by‐product from the pepper stuffed olives, while the stone without seed had the maximum oleuropein content (750.2 ± 85.3 mg kg?1). α‐Tocopherol values were between 79.8 ± 20.8 mg kg?1 in the seed of the olive stone and 6.2 ± 1.2 mg kg?1 in the whole by‐product from the anchovy‐stuffed olives. In light of the results obtained, it would seem possible to use table olive by‐product as a source of natural antioxidants in foods, cosmetics or pharmaceutical products, thus contributing to diminishing the environmental impact of table olive by‐product and to its revalorisation. 相似文献
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While there has been considerable work examining the effect of extraction methods and malaxation conditions on different characteristics of olive oils, there have been few that deal with all the major aspects. Here we have evaluated three different extraction techniques and the influence of time and temperature during malaxation using a major Italian (cv. Coratina) and the main Cretan (cv. Koroneiki) cultivars. Standard characteristics were measured as well as detailed analyses of alcohols, steroids and phenolics were conducted. Quality was also assessed by Panel tests. The main variables were the total amount and composition of the phenolics. In turn, this influenced the oxidative stability and sensory quality. It was also clear that the cultivars behaved differently and this prevented general conclusions being made for all of the quality characteristics. 相似文献
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Hisayoshi Soejima Keisuke Tsuge Takashi Yoshimura Kazutaka Sawada Hiroshi Kitagaki 《Journal of the Institute of Brewing》2012,118(3):264-268
A novel breeding strategy for a high tyrosol‐producing sake yeast was developed by isolating an ethanol‐resistant mutant from a tryptophan auxotrophic mutant of a sake brewery yeast. Since tyrosol has antioxidant, cardioprotective and taste‐sharpening effects, increasing the tyrosol level of alcohol beverages could be beneficial in alcohol production. Since the transporters of aromatic amino acids are degraded by several stresses and mutants defective in the synthesis of aromatic amino acids are sensitive to ethanol, it was hypothesized that the degradation of these transporters should be inhibited in ethanol resistant mutants isolated from the auxotrophic mutants of aromatic amino acids, and that the uptake of aromatic amino acids would be increased in the mutants. Consistent with this hypothesis, sake was brewed with the ethanol‐resistant mutant of a tryptophan auxotrophic mutant and the sake was found to contain a lesser content of tyrosine and a higher content of tyrosol relative to the sake brewed with the parental strains. The taste of the sake brewed with the mutant strain could be discriminated from the sake brewed with the parental strains, probably because of the altered concentrations of tyrosol and certain amino acids and organic acids. The results suggest that combining the isolation of an ethanol‐resistant mutant and an auxotrophic mutant is an effective method to breed a brewing strain with a modified metabolism of these substances. Copyright © 2012 The Institute of Brewing & Distilling 相似文献
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M. Akasbi D. W. Shoeman A. Saari Csallany 《Journal of the American Oil Chemists' Society》1993,70(4):367-370
A reverse-phase high-performance liquid chromatographic technique with isocratic elution has been developed to separate and
quantitate the major phenolic compounds of the hydroalcoholic extracts of olive oils. Hydroxytyrosol, tyrosol, caffeic acid,p-hydroxyphenylacetic acid and homovanillic acid were analyzed on a μBonapak C18 column with an acetonitrile/water/acetic acid
(20:90:0.18, vol/vol/vol) mixture as a mobile phase. Electrochemical detection provided selectivity as well as sensitivity.
The method was applied to the analysis of the most important phenolic compounds in olive oils. 相似文献
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