Effect of hydrothermal treatments on the nutritional, functional and storage stability characteristics of decorticated foxtail millet grains and flour

Rapid off-flavor development and bitterness is a major concern during storage of grains and cereal flours, especially millet flour due to the occurrence of rancidity. The pre-treatment of grains before milling ensures the better retention of quality of the grains and flour, thus enhancing their utility in various products. The flour obtained from untreated, soak-boil and soak-steam treated foxtail millet grains was stored at ambient and under refrigerated conditions for 90 days. The % FFA content of untreated, soak-boil and soak-steam was 0.49, 0.22 and 0.21 %, respectively which increased significantly to 0.68, 0.28 and 0.26 % oleic acid after 90 days at storage at ambient conditions. The last phase of storage depicted a significant increase in the peroxide value and FFA of untreated samples. Under refrigerated conditions the flour obtained from soak-steamed grain had a better storage stability, functional characteristics than soak-boiled grains, and those stored at ambient temperature. The moisture, carbohydrates, FFA, peroxide levels increased, whereas antioxidant activity, pasting properties, decreased significantly during 90 days of storage. The current investigation reveals that the hydrothermal treatments by soak-boil and soak-steam methods could be effectively used to prolong the storage period of millet grain and milling fractions for better utilization.