Total phenolic, flavonoid and antioxidant capacities of processed pearl millet and sorghum flours

Abstract

This study assessed the effects of sprouting and fermentation on total phenolic content, total flavonoid content and antioxidant property of pearl millet (Pennisetum glaucum) and sorghum (Sorghum bicolor). Pearl millet and sorghum were subjected to the treatment of sprouting and fermentation for 0 h, 24 h, 48 h, 72 h and 96 h. After each of the treatments, the samples were oven-dried at 60 oC for 24 h and milled into fine flour of 0.05 mm in size. The total phenolic content, flavonoid content and antioxidant capacities were quantified using standard methods. The results of the study revealed that sprouting significantly (p<0.05) increased the total phenolic, total flavonoid and antioxidant capacities of pearl millet and sorghum. However, sprouting time significantly (p<0.05) reduced the total phenolic content of pearl millet. A similar trend of increment was observed in fermentation where there was a significant (p<0.05) increase in the total phenolic, total flavonoid, reducing the power and antioxidant capacities of pearl millet and sorghum with an increase in fermentation time. Therefore, the results of this study revealed that the two bioprocesses (sprouting and fermentation) significantly increased the total phenolic, total flavonoid and antioxidant capacities of pearl millet and sorghum. However, pearl millet exhibited reduced TPC with an increase in sprouting time.