Effect of enzyme – assisted extraction on total polyphenol content and antioxidant capacity from fresh tea leaves (Camellia sinensis)

Abstract

Tea leaves contain high concentration of polyphenols, known as bioactive compounds. In order to increase the extraction yield of polyphenol and the antioxidant capacity of the extract from tea leaves, the combination of cellulase, pectinase and protease in enzyme-assisted extraction was investigated. By using fractional factorial experimental design to study the two-enzyme assisted extraction of cellulase and pectinase, three factors including solvent/material ratio, pH and hydrolysis time showed significant effects on the extract properties. The highest total polyphenol content obtained adopting the favorable conditions was 185.9 mg GAE/g of dry material at solvent and material ratio of 5.9, hydrolysis pH of 4.4 and hydrolysis time of 36 minutes. In addition, the antioxidant capacity of the extract was determined at 175.9 mg TE/g of dry material at those optimum experimental conditions. In our test of three-enzyme (cellulase – pectinase – protease) assisted extraction, the extracts were spray-dried to observe green tea powder. Results indicated that the TPC, AC and the color sensory quality of the green tea powder decreased compared to the two-enzyme (cellulase – pectinase) assisted extraction.