Effect of the distillation process on polyphenols content of grape pomace

Grape pomace is a winery by-product that is more and more valorized as a source of healthy bioactive molecules such as polyphenols. In addition, it can be used to produce some alcoholic beverages, such as grappa, which is a typical distilled Italian alcoholic product. The spent grape pomace after grappa elaboration is mainly considered a food waste. The aim of this study was to reconsider and valorize red and white pomaces obtained after the production of grappa. The total phenolic content of both samples, as well as the antioxidant activity had a decrease after the distillation; however, it was not significant in the case of red pomace. Regarding the phenolic profile, the behavior during the distillation was different, according to the type of pomace. After the grappa production, catechins and epicatechins were the most significant phenolics in white and red pomace, respectively, demonstrating the remaining bioactivity of this by-product, which could be useful within the food industry.