1,721,119 research outputs found

    Changes in quality indices, phenolic content and antioxidant activity of flavored olive oils during storage

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    The chemical characteristics, phenolic content and antioxidant activity of olive oils flavored with garlic, lemon, oregano, hot pepper, and rosemary were evaluated during 9 months of storage. At the end of the storage period, the unflavored and the garlic-flavored oils maintained their chemical parameters within the limits fixed for extra-virgin olive oils. After 9 months of storage, a noticeable decrease in phenolic content was observed in all the oils. The highest (35.0 ± 3.9 mg/kg oil) and the lowest (6.3 ± 0.4 mg/kg) phenolic contents were detected in the unflavored and garlic-flavored oils, respectively. Compounds such as 3,4-DHPEA-EDA (3,4-dihydroxyphenylethyl 4-formyl- 3-formylmethyl-4-hexenoate, the dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol) and p-HPEA-EDA (dialdehydic form of the decarboxymethyl elenolic acid linked to tyrosol) were the most abundant in both unflavored and lemon-flavored oils up till 6 months of storage. At the end of the storage period, increases in 3,4-DHPEA (hydroxytyrosol) and p-HPEA (tyrosol) were measured in almost all the oils. During storage, the antioxidant activity coefficients of the phenolic extracts, calculated according to the b-carotene bleaching assay, significantly decreased and, after 9 months, were in a decreasing order: rosemary (51.3 ± 4.2), hot pepper, lemon, oregano, unflavored, and garlic (8.5 ± 0.7)

    Evaluation of isoflavone content and antioxidant properties of soy-wheat pasta

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    The purposes of this work were to determine isoflavones profile and antioxidant activity of two soy flours and spaghetti produced from semolina blended with increasing amount of these flours. Defatted and toasted soy flour (DSF and TSF, respectively) showed different isoflavone profiles though glucosides were the most abundant isoflavone forms in both the meals. The pasta-making procedure determined an increase of the aglycone forms that was at least 37 and 21% in TSF and DSF pasta, respectively. Cooking operations induced severe decreases of the isoflavone content (the losses ranged from 60.44 to104.91 mg kg)1 for TSF pasta and from 85.41 to 469.33 mg kg)1 for DSF pasta). The results of the antioxidant activity were quite different as a function of the methods applied but they resulted generally well correlated with the isoflavone contents of the samples. Cooking induced significant decreases of the antioxidant activity in almost all samples. This result appears well correlated with the decrease of the total isoflavone content and the presence of antioxidant activity in the cooking water

    Phenolic content and antioxidant activity of Primitivo wine: comparison among winemaking technologies

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    The aim of this study was to assess the influence of 9 winemaking technologies (traditional, delestage, saign ́ee, delayed punching-down, addition of grape seed tannins, addition of ellagic-skin-seed tannins, heating of must-wine, cryo-maceration, and prolongedmaceration) on the phenolic content and antioxidant activity of Primitivo musts and wines. Three methods for the determination of the antioxidant activity were compared: DPPH, β-carotene bleaching assay, and ABTS. Oenological parameters and composition of the phenolic fraction of 1-y-aged wines was also determined. The addition of tannins allowed the increase of the phenolic content of musts and wines in a greater amount than the other technologies. The results concerning the antioxidant activity depended on themethod applied. Concerning musts, the DPPH assay did not highlight great differences among technologies, whereas the addition of tannins allowed the obtainment of the highest antioxidant activity according to β-carotene and ABTS assays. The wine aging determined an increase of the antioxidant activity, independently on the method applied. Wine obtained through traditional technology, saignee, and addition of tannins showed the highest antioxidant activities according to DPPH and β-carotene. The highest correlation coefficients (0.961 and 0.932) were calculated between phenolic content and ABTS values of musts whereas the lowest values (0.413 and 0.517) were calculated between phenolic content and ABTS values of wines. Wines produced through traditional technology were the richest in anthocyanins. The addition of tannins allowed to obtain high content in monomeric anthocyanins, flavonoids, flavans reactive to vanillin, and coumaroylated malvidin and a low content in acetylated malvidin
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