Temperature Dependent Hydration Kinetics of Finger Millet (Eleusine coracana) and Foxtail Millet (Setaria italica) Grains

Abstract

Hydration kinetics of finger millet (Eleusine coracana) and foxtail millet (Setaria italica) grains were studied at temperatures between 30 - 70°C by estimating moisture contents at different durations of soaking. Initial moisture content of finger millet and foxtail millet grains were 12.29% (d.b.) and 12.04% (d.b.) and at saturation, attained the moisture content of 53.01 - 60.92% (d.b.) and 40.93 – 46.33% (d.b.), respectively. Finger millet took about 16 h to reach saturation moisture content at soaking temperature of 30°C and 2 hours at 70°C. In the case of foxtail millet, it took 3.5 h at 70°C and 17.5 h at 30°C. The moisture content with respect to duration were well fitted to Lewis, Page, modified Page and Peleg models with coefficient of determination of 0.92 - 0.99. Among these models, Peleg model suggested a good fit for finger millet, and Page and Peleg models for foxtail millet grains. The dependency of the coefficients of the hydration models with soaking temperature was found to be linear for both little and proso millets with coefficient of determination ranging from 0.88 to 0.97.