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Application of hyperspectral imaging for prediction of quality characteristics and sensory attributes of table grapes
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Phenolic content and antioxidant activity of Primitivo wine: comparison among winemaking technologies
No full textThe 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
Changes produced in extra-virgin olive oils from Coratina cv. during a prolonged storage treatment
No full textExtra-virgin oil is obtained from olive fruits only by mechanical means. The quality of extra-virgin olive oils is affected mainly by hydrolytic and oxidative reactions. For this reason, the commercial shelf-life is usually no longer than 18 months. In order to investigate the effects of a prolonged storage, olives from cv. Coratina were crushed using a three phase system to produce extra virgin olive oil analysed for sensory and chemical-physical indices, phenolic profile, tocopherol content, and antioxidant activity during a 8-years storage. The oil lost its characteristics of extra-virgin after 6 years of storage, time at which the median of the defects was higher than 0 and free acidity exceeded the limit fixed for this category by the European Regulation whereas the stability against oxidation persisted for a longer period due to the high concentration of oleuropein derivatives. A strong positive linear correlation was observed between the phenolic content and antioxidant activity measured according to the ABTS+. to indicate a noticeable radical scavenging ability of phenolic compounds
Effects of cultivars and location on quality indices, phenolic content and antioxidant activity of extra-virgin olive oils
No full textEvaluation of isoflavone content and antioxidant properties of soy-wheat pasta
No full textThe 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
Changes in quality indices, phenolic content and antioxidant activity of flavored olive oils during storage
No full textThe 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)
Effects of processing on quality, phenolic composition, and antioxidant activity of Autumn Royal seedless table grape purees
No full textEffects of different vinification technologies on physical and chemical characteristics of Sauvignon blanc wines
No full textIn order to investigate the effects of cryomaceration and reductive vinification on chemical and physical indices and on antioxidant compounds of Sauvignon blanc wines, four wine-making procedures were applied: traditional white vinification, skin cryomaceration, vinification in a reductive environment, and a combination of the last two procedures. Significant differences were highlighted by both conventional analyses and NMR spectroscopy. The strongest changes were for organic acid concentrations (tartaric, in particular) and phenolic content. Cryomaceration caused a strong precipitation of tartaric acid, which may be desired if grapes have high acidity values. Cryomaceration protected those fiavans reactive with vanillin from the action of oxidative enzymes. Vinification in a reductive environment, alone or combined with a cryomaceration step, gave wines with the highest solids content and caused a greater extraction of phenolic compounds from skins compared to traditional winemaking or cryomaceration alone, due to SO2 solubilisation. Grape oenological expression can be strongly affected by the application of the investigated wine-making procedures. (C) 2012 Elsevier Ltd. All rights reserved
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