Antioxidant activities of volatile and non-volatile fractions of selected traditionally brewed Korean rice wines

Abstract

Antioxidant activities of traditionally brewed Korean rice wines have recently been reported. The objective of this study was to identify the antioxidant activities of the volatile and non-volatile fractions of three Korean rice wines, and further to identify the active ingredients responsible for the antioxidant properties. Volatile and non-volatile components of three rice wines, Measilju, Kukwhaju and Gugijaju, were separated into seven fractions according to their polarities. Antioxidant activities were determined by an aldehyde-carboxylic acid assay for the volatile fractions and a lipid-malondialdehyde assay for the non-volatile fractions. Volatile constituents of each fraction were identified and quantified using gas chromatography-mass spectrometry. In addition, antioxidant activities of specific authentic chemicals from the volatile fractions of the wines were measured, and the antioxidant properties of the volatile fractions were determined. Identification of volatile compounds potentially showing high antioxidant activities were conducted in each fraction of the three wines. Among the volatile compounds identified from volatile fractions of the wines, benzeneethanol, 2-furanmethanol and 4-ethyl-2methoxyphenol showed the highest antioxidant activities, when added at higher concentrations (~100μg/g). Identification of antioxidant properties, as well as the specific compounds responsible for these antioxidant properties, could aid Korean rice wine product developers, in terms of strategic planning for sales in the Korean market.