Grape pomace, a by-product of wine-making, is rich in polyphenols, metals, organic acids and can become a functional ingredient in food and beverage. The stabilisation of the pomace has been optimised to preserve the anti-inflammatory and antioxidant properties of the molecules present. Isolated grape skins have been reused in purity or in blends with other plant components as a base for: 1) herbal teas, 2) ready-to-drink functional beverages, 3) freeze-dried products. The beverages obtained are rich in polyphenols, mineral salts, organic acids and possess biological activity. The anti-inflammatory, endothelium-protective effect of aqueous grape pomace skin extracts has been demonstrated through the adhesion of endothelial monocytes, the first step in the development of atherosclerosis, and the expression of adhesion molecules in human endothelial cell culture. The extract reduces the expression of endothelial adhesion molecules (ICAM-1 and VCAM-1) at the lowest concentration used. Anti-inflammatory activity is enhanced in the infusion of pomace and tea, suggesting a possible synergistic effect for the development of a functional beverage.
The new food products in the research phase possess the following competitive advantages: 1) development of a sustainable methodology that allows to transform an industrial waste into a second stable raw material, ready for a new industrial chain; 2) use of dehydrated skins separated from marc as a second raw material for the production of functional drinks rich in polyphenols and mineral salts. The drinks obtained from the blend of grape skins and black tea have a very high quantity of polyphenols and a very high antioxidant activity when compared with drinks on the market. In addition, the synergistic effect between the polyphenols in tea (catechins) and those in the skins (anthocyanins) allows for a high anti-inflammatory and protective activity on endothelial cells in vitro. The new functional drinks aim to achieve the following sustainability objectives in the National Strategy for Sustainable Development: 1) promote social and environmental responsibility in companies and administrations; 2) reduce the production of waste and promote the market for secondary raw materials; 3) develop a market for novel functional products.