Thermal treatment in combination with laminated packaging under modified atmosphere enhances the shelf life of pearl millet flour

Abstract

Pearl millet grain is storable for months without development of rancidity, while milled flour has very short shelf life of 5 to 7 days due to high fat content and lipolytic action of enzymes. Apart from enzymatic degradation of lipids and c-glycosyl flavones, oxygen present in air promotes oxidation of free fatty acids (FFA) leading to production of peroxides which impart off flavours and bitterness. To control both enzymatic and oxidative effects, implementation of an integrated approach of thermal treatment, efficient packaging, and modified atmosphere was used for shelf life extension. Heat treatment of grains at 150 °C for 30 min before milling and storage of flour in laminated pouches under nitrogen atmosphere was found to extend shelf life by 60 days compared to untreated samples by decreasing FFA value by 10–15 fold and peroxide value by 2 fold. Genotype, thermal treatment, packaging material and atmosphere were found to be significantly different for rancidity parameters.

Keywords

• Pearl millet
• Packaging
• Rancidity
• Shelf life
• Thermal