Optimization of enzymatic hydrolysis of persimmon peels for vinegar fermentation

Abstract

Response surface methodology (RSM) was used to determine the treatment conditions of optimal enzymatic hydrolysis for vinegar preparation from persimmon peel. Persimmon peel was hydrolyzed with different concentrations of Viscozyme L (0–4%) at different temperatures (40–60°C) for different lengths of time (2–10 h) followed by vinegar fermentation. Reducing sugar and soluble solids of the hydrolyzed juice were significantly affected by the hydrolysis conditions. Optimal condition was obtained with the enzyme concentration of 2.38 g/100 mL, reaction temperature of 49.19°C, and reaction time of 6.32 h. The titratable acidity of vinegar prepared from the juice hydrolyzed under the optimized condition increased by 276% (4.25 g/100 g). Acetic acid, citric acid, oxalic acid, and succinic acid were identified in the vinegar. Results suggest that the enzymatic hydrolysis pretreatment could be used for increasing the yield of the vinegar fermentation.