Effect of processing methods on the nutraceutical and antioxidant properties of little millet (Panicum sumatrense) extracts

The effect of germination, steaming and roasting on the nutraceutical and antioxidant properties of little millet (Panicum sumatrense) was investigated. The nutraceutical properties were determined by evaluating the total phenolic, flavonoid and tannin contents while the antioxidant properties were studied by the DPPH free radical scavenging activity and the iron reducing power assay. The results showed that the total phenolic, flavonoid and tannin contents of processed little millet increased by 21.2, 25.5 and 18.9 mg/100 g, respectively, compared to native sample. The DPPH radical scavenging activity and the iron reducing power of roasted millet extract were the highest compared to the other processed millet. Fractionation of phenolic extracts by HPLC showed that the analytes were derivatives of benzoic acid (gallic acid, proto-catechuic acid and vanillic acid), aromatic carboxylic acid (gentisic acid) and cinnamic acid (syringic acid and ferulic acid). The results indicate that processing has significant effects on the nutraceutical and antioxidant properties of little millet phenolic extracts.