Elucidation of temperature dependent hydration behaviour of chickpea seeds: Prerequisite for germination

Abstract

Soaking to a desirable extent of moisture is an unavoidable prerequisite in the utilization of chickpea seeds. Partially hydration of chickpea before germination, roasting or puffing of chickpea is a common practice for its propagation and preparation of ready-to-eat confectionary products. Almost completely soaked chickpeas are preferred in making soaked chickpea, sprouts, baked chickpea, and various cooked delicacies. The present research was carried out to study the hydration characteristics of chickpea seeds. Water absorption characteristics in terms of weight gain were investigated, and the process was segregated into three different phases comprising of rapid water absorption phase (Phase I), slow water absorption phase (Phase II) and termination phase (Phase III). Three empirical models, namely the Newton model, Henderson and Pabis model, and Weibull model, were used to assess their adequacy to describe temperature (10–60 °C) dependent water absorption phenomenon. Weibull model was found to describe the water uptake phenomenon better than the Newton and Henderson and Pabis models. The Arrhenius plot for Fick's law of diffusion was used to calculate the activation energy. It was observed that breakpoint occurs at 41.67 °C, correlated with the thermal glass transition of seed coat during soaking. Germination potential of chickpea seeds at different soaking temperatures was also investigated. Effect of soaking and germination of chickpea seeds on thermal properties and x-ray diffraction pattern were also studied.