Textural degradative kinetics of selected legumes of Punjab

In order to consume the whole grains of stored legumes, it needs to be softened. The soaking procedure is commonly practiced without technical know how of time -temperature combination on textural changes. To study the variations in the hardness with different hydration/soaking temperature and time combinations, five different types of legumes commonly grown in Punjab i.e., green gram chickpea (desi and kabuli), soybean and Fieldpea were selected. The pulses were hydrated by soaking at different temperature varying from 30–70°C for regular time period. The effect of soaking on texture was measured instrumentally with the help of texture analyser using 75 mm compression plate at a speed of 1mm sec⁻¹. The texture degradation followed first order kinetics. The rate of hardness decay was estimated to be highest (0.0259 gm_f/min) for kabuli chickpea and minimum for (0.0126 gm_f/min) for soybeans. A mathematical relationship was developed using the rate constants of texture. The activation energy of 1.54x10⁴ kJ/kg mole was found to be maximum for desi chickpea and minimum (0.460x10⁴ kJ/kg mole) for green gram. The water absorption was observed to be highest for soybean and lowest for green gram.