Fig.2.

HPLC chromatograms of unripe apple polyphenol extracted (a) without and (b) with Viscozyme L-aided condition

1: 5-hydroxymethyl furfural; 2: protocatechuic acid; 3: procyanidin B1; 4: (±)-catechin; 5: chlorogenic acid; 6: caffeic acid; 7: (−)-epicatechin; 8: p-coumaric acid; 9: ferulic acid; 10: quercetin-3-D-galactoside; 11: quercetin-3-glucoside; 12: quercetin-3-rhamnoside; 13: phloridzin; 14: quercetin; 15: phloretin; 16: kaempferol; UK1~9: unknown. Reaction: the ratio of Viscozyme L to substrate 0.02 (2 FBG), pH 3.7, 50 °C, 12 h; Extraction: 70% ethanol, 85 °C, 12 h