Boiling time variation through functional characteristics of boiled red kidney beans

¹ Department of Food Technology, Faculty of Agricultural Technology, Widya Mandala Surabaya Catholic University, Jl. Dinoyo 42-44 Surabaya, Indonesia
² Postharvest Engineering Laboratory, Faculty of Agriculture, Gifu University, 1-1 Yanagido Gifu, Japan

^* Corresponding author: maya@ukwms.ac.id

Abstract

Chemical components of red kidney beans, starch and protein, closely related to its functional properties. The starch and protein components are structurally still bound to each other or to other components in a complex structure which can hinder the utilisation of the functional properties of red kidney beans in food products. Utilisation of the red kidney beans based on the functional properties requires preliminary treatment, namely boiling. Boiling time was an important factor that may affect its functional properties. The purpose of this study was to determine the effect of boiling time on the functional properties of boiled red kidney beans. Six levels of boiling time (0, 3, 6, 9, 12 and 15 min) were applied with three replications. Functional properties tested included protein solubility, water absorption, oil absorption, gel formation, foam capacity and stability, emulsion capacity and stability, and moisture content. The results showed that boiling decreased protein solubility, foam capacity, and emulsion capacity of red kidney beans, while the foam stability and emulsion stability increased with the length of boiling time. The absorption of water and oil increased up to 9 min of boiling, while the moisture content increased after 3 min of boiling.