Enzymatic Processing of Plant Extracts

Food grade cellulase (within a pH range of 3.0 to 6.5 and a temperature range of 35 to 75 °C), xylanase (within a pH range of 4.0 to 9.0 and a temperature range of 25 to 75 °C), and pectinase (within a pH range of 3 to 6.5 and a temperature range of 35 to 75 °C) were purchased from Winovazyme (Beijing, China). Porcine pancreatic α-amylase (with an optimal temperature of 20 °C and an optimal pH of 7.4), porcine pancreatic lipase (with an optimal temperature of 37 °C and an optimal pH of 7), and lysozyme were purchased from Sigma Aldrich (St. Louis, MO, USA). Tannic acid, methyl gallate, gallic acid, rhodanine, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), potassium sulfate, quercetin, and Folin-Ciocalteu’s phenol reagent were all of analytical grade and of the highest quality available from Sigma-Aldrich. High-performance liquid chromatography (HPLC) grade standard (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-gallocatechin gallate (GCG), (-)-catechin gallate (CG), (-)-gallocatechin (GC), (+)-catechin (C), caffeine, and gallic acid (GA) were all purchased from Sigma. All chemicals used for antioxidant activity assays and enzyme production were of analytical grade and were obtained from RCI Labscan (Bangkok, Thailand). The medium ingredients used in this study, such as agar, yeast extract, and malt extract, were all purchased from HiMedia (Nashik, India).