Rancidity Matrix: Development of Biochemical Indicators for Analysing the Keeping Quality of Pearl Millet Flour

Abstract

Millets are known for its nutritional excellence because of its high nutrient density. Among all the millets, pearl millet is considered the most important nutricereals, having 3–8% lipids. Rancidity or off-odour development in flour is one of the major limiting factors in the popularization of pearl millet all over the world. In the present investigation, we have evaluated the flour (freshly milled and 10 days after milling) of diverse genotypes of pearl millet for their hydrolytic and oxidative degradation of lipids using different biochemical parameters such as comprehensive acid value (CAV: the number of milligrammes of potassium hydroxide required to neutralize the free fatty acids present in 1 g of flour), comprehensive peroxide value (CPV: determination of the primary oxidation product i.e. hydroperoxides in the flour) and activities of lipase and lipoxygenase (LOX). We have classified pearl millet genotypes into low, medium and high rancid groups and developed a rancidity matrix (RM) with 3 groups and 6 classes; the matrix was validated using 93 diverse pearl millet genotypes. RM will be of great help to the pearl millet breeders for developing low rancid pearl millet lines.