Identification of Bioactive Compounds From Vitis labrusca L. Variety Concord Grape Juice Treated With Commercial Enzymes: Improved Yield and Quality Parameters

In this work, the effects of eight different enzymatic preparations were compared in terms of the extraction of bioactive compounds as well as the yield and quality of grape juice from Vitis labrusca L. variety Concord. Juices were prepared by enzymatic treatment and the used preparations were characterized through five enzymatic activities: total pectinase (PE), polygalacturonase (PG), pectinlyase (PL), pectin methyl esterase (PME), and cellulase (CE). Quality parameters such as color, total soluble solids (°Brix), reducing sugars, titratable acidity, pH, and antioxidant capacity were determined for all samples. Phenolic compounds and anthocyanins were identified and quantified by HPLC-DAD-MS. Juice yield was improved by preparations with high activities of PG, PME, and PL, up to 9 % higher than the control, when used Pectinex Ultra Clear. For the extraction of bioactive compounds, the highest values were found for preparations with high CE activity. Regarding the phenolic compounds, 15 compounds were identified. The content of caftaric acid and total anthocyanins was improved up to 300 and 60 %, respectively, using Lallzyme Beta. It was possible to understand the role of each enzyme in the extraction of yield, quality parameters, and bioactive compounds. Pectinex Ultra Clear was the preparation that provided the highest yield and Lallzyme Beta the highest bioactive compounds concentration. For a good quality juice and high yields for the industry, it is important to have a good balance of pectinases and cellulases.