Comparative analysis of pre-fermentation treatments on phenolic compounds and bioactivity in Vitis Vinifera var. Syrah and var. Cabernet Sauvignon grapes

This study investigated the effect of pre-fermentation treatments on the phenolic compounds and biological activities of red grapes of Vitis vinifera var. Syrah and var. Cabernet Sauvignon Syrah and Cabernet sauvignon musts from two different regions and consecutive vintages. Specifically, cold soak at 10 °C and heat maceration at 60, 70, and 80 °C were compared to classical winemaking (maceration and fermentation at 25 °C). High-performance liquid chromatography/diode array detector (HPLC/DAD) was used to characterize the main classes of polyphenolic substances, and biological activities were determined through assays for antioxidant, anti-inflammatory, anti-hyperuricemic, anti-Alzheimer, anti-diabetic, and antiproliferative activities. The findings showed that temperature played a significant role in anthocyanin and tannin extraction. The data also revealed moderate positive correlations between dimers procyanidin B1, B2, and caffeic acid with antioxidant activities (ABTS and DPPH), a strong positive correlation between gallic acid and anti-inflammatory activity, another strong positive correlation between gallic acid and anti-diabetic activity, and a moderate correlation between anticancer activity in human breast cancer cells (MCF7) with resveratrol. In conclusion, this study provides valuable insights into the effects of different pre-fermentation treatments on the phenolic composition and biological activities of Syrah and Cabernet sauvignon musts, which may have implications for the development of new winemaking techniques.