Antioxidant activity and volatile components of sprouted oat beer
Da Song, Kwon-Jai Lee, Jeung Hee An
Abstract
This study aimed to explore whether oats can be used as a partial substitute for barley in beer brewing. The antioxidant activities of oats, oat malt, and oat beer were measured, and the volatiles present in them were identified using an electronic nose and tongue. The total polyphenol content was higher in oat malt than in oats. The total polyphenol and flavonoid contents in oat beer increased with increasing oat malt concentration. However, tannin content did not significantly change with increasing oat malt concentration. The scavenging activity of oats and oat malt were at 6–23% and 3–19%, respectively, against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 17–80% and 13–83%, respectively, against 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical. The reducing power of oats and oat malt increased in a dose-dependent manner. The highest radical scavenging (1 mg/mL DPPH and ABTS) was observed in 0%, 5%, and 10% oat beers. The reducing power of oat beer was highly dependent on oat malt concentration, with a 0.2–1.0 optical density range. The electronic nose detected 61 compounds, including antioxidant terpenes. This study demonstrates that new types of beer with different flavors and high antioxidant capacities can be prepared using oats grown in South Korea.