Enhancing Storage Stability of Pearl Millet Flour through Microwave Treatment

Abstract

Pearl millet (Pennisetum glaucum) is hypothesized to have originated in Central Africa. It predominantly thrives in tropical semi-arid regions of Africa and Asia and typically attains a height ranging from 0.5 to 4.0 meters. The grains of pearl millet are nutritionally rich, containing substantial amounts of protein, vitamins, minerals, and energy, comparable to or surpassing the nutrient profiles of other major cereals. The fat content in pearl millet grains ranges between 4.36% and 7.11%, exceeding the lipid levels observed in many other cereal grains. However, flour derived from pearl millet is susceptible to degradation, particularly under conditions of moderate moisture and oxygen exposure, resulting in reduced shelf life. Microwave heat treatment has emerged as a cost-effective and efficient method for enhancing the storage stability of pearl millet flour due to its precise control over heating parameters compared to conventional techniques. Among eight microwave-treated samples, treatment T7, involving 100 seconds of microwave exposure for 600 grams of pearl millet grains, was identified as the most suitable approach for improving the storage stability of the flour. Experimental data indicated increases in lipase activity, fat acidity, and peroxide value during storage. These changes were statistically insignificant within the first 15 days but became significant after 15 days, signaling enzymatic and oxidative lipid degradation. This degradation contributes to quality deterioration and potential rancidity. Overall, microwave treatment of pearl millet grains for 100 seconds is recommended as an effective method to enhance the storage stability of the resulting flour for up to 15 days.