The use of an enzymatic extraction procedure for the enhancement of highland barley (Hordeum vulgare L.) phenolic and antioxidant compounds

Abstract

A multistep enzymatic extraction method was compared with a conventional chemical extraction process to evaluate the phenolic content and antioxidant activity of highland barley (Z2, Zangqing 25; CHQK, Changheiqingke). The main phenolic compound extracted was (+)-catechin, followed by ferulic acid, p-coumaric acid, caffeic acid and chlorogenic acid. The multi-enzymatic digestion yielded a higher retrieval of (+)-catechin compared to the conventional chemical extraction procedure (P < 0.05). Compounds obtained from the multi-enzymatic digestion process exhibited significantly higher (P < 0.05) antioxidant activities determined by oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) when compared to chemical extracts. These results suggest that highland barley subjected to in vitro multi-enzymatic digestion exhibits a higher phenolic content and antioxidant activity than the chemical extraction, and this multi-enzymatic digestion coupled with the CAA assay may be a valuable tool to evaluate the antioxidant potential of wholegrains and fruits, as well as vegetables.