Antioxidant and polyphenol oxidase activity of germinated barley and its milling fractions

Eight different hulled barley cultivars were evaluated before and after germination for total phenolic content (TPC), antioxidant activity (AOA) and polyphenol oxidase (PPO) activity. Germination for 12 h significantly decreased the TPC in whole flour (WF), bran (B) and refined flour (RF), however, further increase in germination to 24 h significantly increased the TPC in the fractions. Germination for 12 h duration significantly increased the AOA for WF, B and RF and further increase in germination to 24 h significantly increased the AOA in all the barley cultivars tested. A strong positive correlation was observed between AOA and TPC. Upon germination for 12 h the polyphenol oxidase activity of WF, B and RF significantly decreased by 13.31–59.22, 1.93–59.46 and 7.08–45.87%, respectively, however, the PPO activity increased upon germination for 24 h. The highest level of TPC and AOA was observed in the bran fraction of all the barley cultivars.