A comparative study on the nutraceutical potentials of little and barnyard millet varieties

Abstract

Different varieties of little and barnyard millets were evaluated for total polyphenol, flavonoid, tannin and phytate contents, along with their antioxidant potentials in terms of DPPH, ABTS, FRAP, total antioxidant capacity, and reducing power. A wide variation was observed in the nutraceutical contents and their contribution towards the antioxidant potential across the varieties. It was observed that the OLM-208 variety of little millet contained highest polyphenols (72.11 mg/100g), flavonoids (17.9 mg/100g) and tannins (8.46 mg/100g) and lowest phytates (0.62 mg/100g). Among the barnyard millet varieties, MDU-1 contained highest quantity of all the nutraceuticals. The traditional varieties of little millet showed nutraceutical contents comparable to the hybrid varieties, while the traditional barnyard millet variety exhibited lowest values for all the parameters, but showed significant antioxidant activities may be due to the effect of individual phenolic acids. The correlation coefficient of polyphenols with antioxidant activity was 0.79 and with DPPH was 0.71 for little millet. For barnyard millet the correlation coefficient of polyphenols with FRAP was 0.98, while that of flavonoids with reducing power and ABTS were 0.99 and 0.95, respectively, and the phytates exhibited a correlation coefficient of 0.91 and 0.94 respectively for reducing power and total antioxidants. 3-hydroxy benzoic acid and genistein were the major phenolic acids in all the millet varieties, and hesperidin and kaempferol were major flavonoid components. The presence of luteolin was also prominent in many of the millet varieties.