Bioactive Phytochemical Composition of Grape Pomace Resulted from Different White and Red Grape Cultivars

Grapes are rich in phenolic compounds, being important for human health with anti-inflammatory, antiatherosclerotic, antimutagenic, anticarcinogenic, antibacterial, antiviral, and antimicrobial activity. The winemaking of the grapes generates significant amounts of waste. These wastes contain bioactive compounds in their biomass that can be used as a source of food improvement or as a source of nutrition supplementation. This study looks at the content of bioactive compounds, the polyphenolic profile, and the antioxidant activity in different white and red grape pomaces. The investigation of bioactive characteristics (total polyphenols, total flavonoids, catechins, tannins, and antioxidant activity) was carried out by UV-Vis spectrophotometric methods, while the individual polyphenolic composition was investigated by target and screening UHPLC-HRMS/MS analysis. Principal components (PCA) and the heat maps analysis allows the discrimination between the grape pomace resulted from white grape cultivars (Muscat Ottonel and Tamaioasa Romaneasca) and red grape pomaces (Cabernet Sauvignon, Merlot, Feteasca Neagra, Burgund Mare, Pinot Nore), with the identification of the specific phenolic compounds for each grape pomace type

Assessment of Bioactive Phenolic Compounds in Musts and the Corresponding Wines of White and Red Grape Varieties

Wine contains important amounts of antioxidants, which contribute to the protection of the body from oxidative stress and associated diseases. This study aims to characterize the bioactive characteristics and individual polyphenolic composition of different white and red musts and the corresponding wines obtained at Stefanesti vineyard, Romania, and to observe the evolution of the main phenolic compounds from the musts to the corresponding wines. General bioactive characteristics (total polyphenols, total tannins, total catechins, total anthocyanins contents, total tannin, and antioxidant activity) were determined using UV-Vis spectrometric methods, while phenolic composition (phenolic acids, flavonoids, and stilbenes) was detected using UHPLC–HRMS analysis. The fermentation and stabilization processes that occur during the transformation of musts into the corresponding wines lead to a decrease in the general bioactive characteristics from musts to wines, while the fermentation of the musts leads to an enrichment of the individual phenolic compounds in the corresponding wines, with a significant increase in the content of gallic, syringic, and p-coumaric acids in the wines compared with the musts. A clear distinction of the musts and wines was obtained for both white and red varieties, indicating different phenolic compositions of the musts and wines. The obtained results contribute to the characterization of the polyphenolic fingerprint of the investigated white and red musts and wines