ENZYME-AIDED EXTRACTION OF POLYPHENOLS FROM GRAPE POMACE

Nowadays, grapepomace is frequently used as a source of polyphenols. With the aim of enhancing the yield of the extraction, the capacity of three commercial enzymatic preparations, Cellubrix® (cellulase and â-glucosidase activities), Neutrase® (protease and á-amylase activities) and Viscozyme® (cellulase, hemicellulase and pectinase activities) was tested in this study. Individually applied, none of the enzymatic formulations was able to improve the efficiency of the aqueous extraction (control). However, acting in combination, a significant increase in the yields of soluble solids (∼20-45%), and phenols (∼25-65%), so as a notable improve in antiradical activity DPPH, with the subsequent decrease when measured as EC50 (∼53-70%) was detected either in a white variety (Garnatxa). as in a red one (Cabernet Sauvignon). Synergistic effect at different dosages (0-30 g Enzyme/Kg substrate) and incubation times (1-2h) was further studied. Significance of dosage was found to be dependent on the grape variety and on the nature of the pomace (pressing, distillation). The highest phenolic yields (2.6-2.8 g/Kg of dry raw material) were obtained when distilled Cabernet Sauvignon pomace was treated with the mixture in a dosage level of 30 g/Kg.