Grapes contain a number of nutritional and functional compounds and are rich in phenolic compounds. The total extractable phenolics in grapes are mainly distributed in skin and seeds in comparison to the pulpand it is the phenolics in the skin that are transferred into the final product by the maceration process in red winemaking. In particular, red wine is rich in phenolic compounds, including flavonoids (anthocyanins, flavan-3-ols, proanthocyanidins or condensed tannins and flavanols) and nonflavanoids (hydroxybenzoic and hydroxycinnamic acids and their derivatives, stilbenes and phenol alcohols) based on grape variety, growing techniques (viticulture) and winemaking conditions.
A study investigated the effects of different maceration times (5, 10 and 15 days) on the composition, phenolic compounds and antioxidant activities of red wines made from the Karaoglan grape grown in Malatya in Turkey. Maceration duration changed some chemical constituents and the colour of Karaoglan red wines. A linear relationship was observed between the antioxidant activity of wine Alcohol consumption and risk of fatty liver disease: a meta-analysis and maceration duration. The major organic acid was tartaric acid which was at the highest concentration in wine macerated for 10 days. A total of 25 phenolic compounds were determined in the wine samples. Within these phenolics; procyanidin B2, trans-caftaric acid, gallic acid, trans-caffeic acid, (+) catechin, (−) epicatechin and quercetin-3-O-glucoside were the most abundant phenolics regardless of maceration duration. In general, extended maceration duration resulted in increase in the concentration of phenolic compounds, reflecting the antioxidant activities of wine.
In conclusion, the highest concentrations of total and individual phenolic compounds as well as antioxidant activities were found in wines macerated for 15 days, the authors state.
Source: Effect of maceration duration on physicochemical characteristics, organic acid, phenolic compounds and antioxidant activity of red wine from Vitis vinifera L. Kocabey, N., Yilmaztekin, M. & Hayaloglu, A.A. J Food Sci Technol (2016) 53: 3557. doi:10.1007/s13197-016-2335-4. First Online: 17 September 2016.