Optimized synchronous extraction process of tea polyphenols and polysaccharides from Huaguoshan Yunwu tea and their antioxidant activities

The synchronous extraction conditions of tea polyphenols (TPP) and tea polysaccharides (TPS) from Huaguoshan Yunwu (HY) tea and antioxidative activities of the extracts were investigated. On the basis of single factor experiments, Box-Behnken design and response surface methodology were applied to optimize the hot water extraction conditions. The optimal extraction conditions were determined as: extraction temperature 99 degrees C, extraction time 175 min, liquid to material ratio 46 mL/g. In such extraction process, the yield of TPP and TPS were 144.68 +/- 5.77 and 61.36 +/- 6.98 mg/g dry basis. The yield of solid hot water extracts (HWE) was 2.47 +/- 0.31%, the contents of TPP and TPS were 614.44 +/- 12.02 and 245.03 +/- 18.12 mg/g HWE, respectively. The antioxidative activities of HWE were estimated by measuring the scavenging activities on DPPH, hydroxyl and superoxide anion free radicals, reducing power and total antioxidant capacity. The results indicated that HWE has high eliminating activities on DPPH, hydroxyl and superoxide anion free radicals, as well as strong reducing power and total antioxidant capability. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.