Major factors influencing antioxidant contents and antioxidant activity in grapes and wines

Abstract

Phenolic compounds in wines, especially in red wines, possess strong antioxidant activity, have the largest effect in decreasing atherosclerosis by both hypolipemic and antioxidant mechanisms. The long-term uptake of red wine has a positive impact on antioxidant activity (AA) of blood plasma in rats in vivo and increases AA by 15%-20% compared to a control group. In the article the effect of total phenolics (TP), total anthocyanins (TA), individual anthocyanins, procyanidins and phenolics contained in red grapes, musts, grape seeds and skins and wines on the AA is discussed. Signifi cant impact of varieties, viticultural regions and locations, climate conditions and vintage has been shown. Likewise, the ways and individual stages of the vinifi cation technology process, and storage conditions affect color, TP, TA, and AA and health aspects of produced wines. Resveratrol, another free radical scavenger mainly contained in the skins of grapes, inhibits the risk of cardiovascular diseases. Higher amounts of trans-resveratrol (RES) have been found in wines from cool and wet climate regions and lesser amounts are typical for warm and dry regions. Changes in the TP content and AA affected by grape variety, vineyard location and winemaking process in white and blue varieties from different vineyards of the Czech Republic were studied. Signifi cant differences in TP among varieties were found. Analysis of variance showed statistically high differences among red and white wines and growing locations. Wines differed signifi cantly in TP content and AA increased signifi cantly during the winemaking process. Statistically signifi cant differences in AA values were found among growing areas, wines and varieties. Signifi cant positive correlations between TP and AA were determined. Total antioxidant status (TAS) of white and red wines (white and blue vine varieties) determined by DPPH and ABTS assays revealed signifi cant differences in AA between white and red wines. Moreover, differences were ascertained between individual varieties of red wine. The results obtained supported the assumption that variety plays a considerable role in TAS; the blue vine varieties showed a much higher TAS. Analysis of variance in AA showed statistically high signifi cance between red and white wines. AA increased during the winemaking process, the highest increase was determined during fermentation and maturation stages of red wine.

Change of selected antioxidant parameters of red wines during maturation

“…On the other hand, following the results of Kondrashov et al (2009), a significant positive relationship between TAC and TPC values was indicated in 6 Cabernet Sauvignon and 4 Merlot wines. The relatively constant total polyphenol content in our results is in accordance with results of Lachman et al (2009) suggesting the relevance of qualitative changes of phenolics. By evaluation of TPC and TAC relationships only a weak dependence was confirmed in Torysa variety (R² = 0.7427), while for the varieties Alibernet and Cabernet Sauvignon no conclusive correlation between the tested TPC and TAC values was found.…”

“…The analysis has shown that in almost all observed parameters the measured values were significantly higher in the varieties with dark-coloured skin and also flesh, in contrast to AA of the Cabernet Sauvignon variety, which has the dark-coloured skin, but the flesh is translucent. This phenomenon can be explained by the substances responsible for AA, which are largely presented mainly in the skin, which was also confirmed by Lachman et al (2009), where the decrease was caused mainly by condensation reactions of flavanols.…”

“…Therefore it can be concluded, if the TPC decreases during aging, the TAC need not decrease regularly. According to Lachman et al (2009), a less significant relationship between antioxidant properties and total phenolics and only a weak relationship between antioxidant activity and total anthocyanin content were also reported. On the other hand, following the results of Kondrashov et al (2009), a significant positive relationship between TAC and TPC values was indicated in 6 Cabernet Sauvignon and 4 Merlot wines.…”

“…Aging is the main factor influencing the antioxidant activity and total polyphenol (TP) content of wines (Lachman et al 2009). The wine with lower phenolic levels is more susceptible to oxidation (Jackson 2014).…”

Comparative Polyphenolic Content of Grape Pomace Flours from ‘Fetească neagră’ and ‘Italian Riesling’ Cultivars

“…Because seed flour did not contain transresveratrol and the concentration in skin flour from 'Italian Riesling' is low, it might be possible that the compound did not rich the detection limit in the mixed flour of the same variety. Lachman et al (2009), also observed that transresveratrol in the must was mainly below the detectable limit.…”