Millet phenolics as natural antioxidants in food model systems and human LDL/VLDL cholesterol in vitro

Abstract

Dehulled grain flour of finger millet (Eleusine coracana), proso millet (Panicum miliaceum) and foxtail millet (Setaria italica) and phenolic extracts of millet hulls were evaluated for ability to inhibit lipid oxidation in several food model systems, namely cooked comminuted pork and fish, roasted peanut butter and gingelly oil. Food samples were kept for 14 days with added millet hull extracts and dehulled grain flours. The percentage inhibition of production of thiobarbituric acid reactive substances (TBARS) during storage was determined. Inhibitory activities of phenolic extracts of finger millet dehulled grain and finger millet foods, namely, Rotti, Pittu, Halapa, Thalapa and porridge, against human very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) oxidation were determined by measuring the production level of conjugated dienes (CD) in vitro. Finger millet had higher phenolic content and antioxidant activities compared to the respective proso and foxtail millet samples. Finger millet hull extracts exhibited the highest inhibition of lipid peroxidation in food model systems. The maximum percentage inhibition of TBARS in pork, fish, and peanut with added finger millet hull extracts were observed at days 3, 7, 5, and 14, respectively. The percentage inihibition of TBARS in cooked pork and fish with added millet hull extracts ranged from 4.4 to 12.8% and 63 to 77%, respectively at the end of the second week. Millet grains and desolventized millet phenolic extracts can act as natural sources of antioxidants at different degrees in pork, fish, peanut and gingelly oil to prevent lipid oxidation during storage.