Quality characteristics and antioxidant activity of makgeolli supplemented with omija berries (Schizandra Chinensis Baillon)

The objective of this study was to evaluate the quality characteristics of the Korean rice wine, makgeolli, supplemented with omija berries (Schizandra Chinensis Baillon) during the fermentation. The changes in pH, total acidity and contents of ethanol, amino acid, total soluble solids, reducing sugar, and total sugar after the completion of fermentation were determined. In comparison with control, omija-supplemented makgeolli showed significantly lower pH (3.46), lower contents of alcohol (17.2%), amino acids (1.85 g/L), and total sugar (17.5 g/L), and higher acidity (12.8 g/L). Moreover, supplementation with omija resulted in significantly higher antioxidant capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities, superoxide dismutase-like activity and reducing power, and higher levels of total polyphenol and flavonoid. Sensory evaluation revealed no significant difference on the overall acceptance, although better appearance and refreshing taste of omija-supplemented makgeolli were observed. Our results indicate that omija represents an effective natural additive for enhancing the biological activities of makgeolli.