Improved Storage Stability of Pearl Millet Flour Through Microwave Treatment

Due to the high fat content and lipase activity, the pearl millet (Pennisetum typhoides) flour had limited shelflife at ambient conditions. The present study was aimed to inactivate lipase in pearl millet grains through microwave treatment. Microwave heating of pearl millet grains decreased lipase activity significantly (p < 0.05) with an increase in moisture level from 12 to 18 % and maximum reduction (92.9 %) was observed at 18 % moisture level for 100 s. Based on lipase inactivation and pasting properties, 80-s duration of microwave exposure at 18 % grain moisture was considered optimum. Significantly (p < 0.05) lower change in free fatty acid (FFA, % oleic acid) value (20.80-22.25) during storage up to 30 days was observed in flour of grains treated for 80 s at 18 % moisture level as compared to control flour (20.11-32.43). Subjective evaluation of overall acceptability of flour samples showed that microwave-treated flour (18 % moisture level, 80 s) was acceptable up to 30 days of storage at ambient conditions, while control flour had unpleasant off odor and bitter taste at the 10th day of storage.