Development of a biofunctional ingredient obtained from Alicante Bouschet grape pomace

Grapes and its by-products are natural sources of bioactive compounds and the benefits of their regular consumption are well-known. Almost 50% of grape crops are destined to winemaking process, generating a large quantity of pomace. Wineries have been seeking for new alternatives for the use of this residue and even aim to achieve the concept of zero residue, which is economically and environmentally interesting. Aiming to develop a future biofunctional ingredient to food and nutraceutical industries, the present study proposed to extract and characterize the antioxidant dietary fibres from grape pomace of Brazilian Alicante Bouschet. The grape pomace obtained had been previously hydro alcoholic extracted assisted by ultrasound and the extract obtained was destined to another study. New aqueous extractions were performed with the grape pomace and an experimental composite design was carried out to evaluate the effects of solute:water ratio, temperature and time of extraction. The aqueous extract (AE) generated was dialyzed by the use of a 6000 Da membrane, obtaining both, retentate (RE) and permeate (PE) extracts. AE and RE samples presented a better recovery of phenolic compounds and anthocyanins, which may be related to the complexation of these compounds with macromolecules, such as polysaccharides. The chemical structure of phenolic compounds enables them to scavenge and neutralize free radicals, explaining the higher antioxidant potential obtained in AE and RE samples. The recovery of antioxidant dietary fibres from the Alicante Bouschet grape pomace has generated a new ingredient of interest for food and nutraceutical industries, enlarging the possibilities of winery residues valuation.