Phenolic and nutritional profiles, and antioxidant activity of grape pomaces and seeds from Lacrima di Morro d'Alba and Verdicchio varieties

Abstract

Grape pomace contains high amounts of bioactive compounds, mainly polyphenols, with different concentrations depending on several factors: grape variety, vinification procedures, even within the same cultivar variation may be due to the geographic regions and wine vintage. Therefore, phenolic, antioxidant, macro- and micro-nutritional composition of wine waste (pomace and seed) originating from Lacrima di Morro d’Alba red grape variety and pomace of Verdicchio white variety were evaluated for the first time. LC-MS/MS analysis showed the presence of 32 phenolic compounds. The phenolic profile was different in pomace of both varieties: white grape pomaces showed the predominance of flavan-3-ols, while anthocyanins were predominant in red pomaces. Comparing seeds and pomace of Lacrima di Morro d’Alba, catechin and epicatechin are representative compounds in red grape seeds, while malvidin-3-galactoside and petunidin-3-glucoside are the most abundant compounds in pomace of all wineries. Highest TPC and antioxidant activities determined by UV–vis spectrophotometer were observed in seed samples. High dietary fibers, polyunsaturated fatty acids, minerals and protein contents were observed in all samples. Wine byproducts of both grape varieties appeared to be a good source of phenolic and nutritional compounds; therefore, they could be a cheap alternative for phenolics production and development of new functional foods.