Hydration Kinetics of Blanched and Unblanched Sword Beans

Abstract

Sword bean, which belongs to the (Fabaceae) family, is an indigenous legume found in several tropical countries in Africa and Asia. During the processing of legumes including sword bean, hydration is initially carried out to prepare the seeds for further operations such as cooking and milling. The absorption of water is determined by the physical and chemical properties of the crop as well as other extrinsic factors such as blanching, temperature, and soaking time. The physical properties of sword bean were determined using the standard method. Arrhenius equation adequately described the temperature dependency of water absorption of sword bean and showed that high soaking temperature reduced the time required to achieve equilibrium moisture. The activation energy for blanched and unblanched sword beans was discovered to be 14.28 KJ/mol and 13.36 KJ/mol respectively. The initial microbial counts on dry beans were minimized by blanching, thus, there was a reduction in risk posed by microbe proliferation during soaking. The quantitative data that characterize soaking conditions is therefore imperative for designing and optimizing food processing equipment, and also predicting the water uptake of the food as a function of time and temperature. The data of hydration kinetics of sword beans will provide information that could be used in solving problems involved in storability conditions, design problems, predict energy requirements in post-harvesting techniques of the product.