The role of dry heat treatment in improving the shelf life of pearl millet flour

摘要

Pearl millet flour cannot be stored for long as its quality undergoes profound deterioration during storage. A study was conducted to explore the effect of dry heat treatment on the shelf life and organoleptic acceptability of pearl millet flour. Free fatty acids and lipase activity had increased almost fourfold in raw pearl millet flour by the end of the storage period, but increases were significantly lower in the flour of heat-treated grains. Acceptability tests showed that flour and chapati prepared from heat treated pearl millet remained organoleptically acceptable during the entire period of storage. Pearl millet flour turns bitter and rancid during storage. This is caused by an active lipase enzyme which is responsible for the breakdown ofglycerides and consequent increase of free fatty acids (Pruthi, 1981). Since this is a major cause of spoilage of pearl millet meal, deactivation of the lipase before milling is essential. The application of dry heat treatment to the grains for 120 min was found to be most effective for maximum retardation of the lipolytic decomposition of lipids during storage (Kadlag et al., 1995).