The Quality of Mulberry Juice as Affected by Enzyme Treatments

Abstract

This study was conducted to investigate the effects of commercial enzymes on the extraction yield and the quality of mulberry juice. A mulberry mash was separately treated with two enzymes, namely Pectinex Ultra SP-L and Viscozyme L for different incubation times from 60 to 240 min. Determination of juice yield, total phenolic content, total anthocyanin content, antioxidant capacity, l-ascorbic acid content, total soluble solids, and titratable acidity of juice were carried out. Overall, in comparison with the non-enzymatic treated juice, the juice incubated with Pectinex Ultra SP-L and Viscozyme L was significantly (p < 0.05) higher in all quality attributes. Moreover, samples incubated with Pectinex Ultra SP-L for 120 min had the highest results in extraction yield (87.1%), total soluble solids (11.9°Bx), titratable acidity (1.4%), l-ascorbic acid content (35.5 mg/100 mL), total phenolic content (160.6 mg GAE/100 mL), and antioxidant capacity (82.6%). For both enzymatic treatments, a prolongation of incubation period from 60 min to 120 min resulted in higher antioxidant values for the juice; however, longer 180 min, they were reduced, except total anthocyanin content. Two-way analysis showed that the impacts of the types of enzyme and treatment duration cannot be separated. Positive correlations between total phenolic content and antioxidant capacity indicated that phenolic compounds were the main antioxidants in the beverages.