The changes of selected phenolic substances in wine technology

Abstract

Abstract:The effects of the pressing technology and clarification of white grape musts on concentrations of phenolic compounds and their antioxidative capacity were investigated. Four different varieties were processed by hydraulic or pneumatic pressing technologies. In the individual stages of pressing and after the application of different doses of the clarification agent, must samples were analysed for the content of polyphenols and the antioxidative capacity. The highest concentrations of caftaric acid were estimated in the musts made by hydraulic pressing from grapes of Welschriesling variety. On the other hand, musts made from grapes of Grüner Veltliner showed the highest contents of trans-piceid in both variants of pressing. The values of antioxidative capacity of the must samples analysed were not significantly different. The influence of clarification on the changes of phenolic substances in young red wines of Saint Laurent variety was also studied. Six various clarifiers were tested as applied in two different doses. Polyvinylpolypyrrolidone caused the highest losses of trans-resveratrol in the course of red wine clarification. The concentrations of catechin, epicatechin, and total anthocyanins as well as the colour parameters of red wines were influenced at most by the application of egg white.

The Use of a Targeted Must Oxygenation Method in the Process of Developing the Archival Potential of Natural Wine

“…The differences in the total phenolics of the must and the wines produced from the grapes harvested from two different localities were not found to be significant. These results do not agree with the claims in [20] that phenolic substances can be good markers of terroir [28]. Differences in the content of the phenolic substances in must in different phases of must pressing were observed.…”

Non‐anthocyanin polyphenolic transformation by native yeast and bacteria co‐inoculation strategy during vinification

“…The residue was re‐dissolved in 1 mL of methanol water (1:1) and filtered through a 0.45‐μm nylon membrane filter. The filtered extract was then subjected to HPLC (e2695; Waters, Milford, MA, USA) as described by Balik et al . with some modifications.…”

Putative Role of Red Wine Polyphenols against Brain Pathology in Alzheimer’s and Parkinson’s Disease

“…The qualitative and quantitative polyphenolic content in red wine depends on numerous factors along the wine-making process, such as (i) environmental factors in the vineyards, e.g., climate, soil, and exposure to fungal infections; (ii) grape varieties and maturity; (iii) pre-fermentative practices, such as addition of sulfur dioxide (SO 2 ) and ascorbic acid (Vitamin C) before grape crushing; (iv) fermenting and aging conditions; and (v) other technological practices, such as ionic exchange, filtration, centrifugation, and cold stabilization ( 35 – 37 ) (Figure 2 ). Of particular importance is the fact that, during wine clarification, there is a decrease in the content of extractive and volatile compounds, which often translates into a significant interference in the content of polyphenols ( 38 ). Furthermore, during wine aging simple phenols present in wine are transformed into complex molecules derived from the condensation of catechins, anthocyanins, and proanthocyanidins.…”