Variety-based physical characterization and pre-gelatinization-induced functional-rheological changes in kidney beans

Abstract

In the present study, three varieties of kidney beans (Red Rajma (RR), Rajma Chitra (RC), and Rajma Sharmili (RS)) were physically characterized and the effect of pre-gelatinization by microwave and hot water on functional and pasting properties of flour were studied. A significant difference was observed in the physical properties of all the kidney beans, indicating that they can be easily characterized and identified based on physical properties. Pre-gelatinization treatment led to variation in color, functional and pasting properties of flours. Color parameters L*, b*, chroma, and hue values reduced with the treatment, whereas a* and total color difference (Δ E) values increased. Water absorption capacity (WAC) and oil absorption capacity (OAC) varied in the range of 1.15–1.91% and 1.25–1.75% for microwave and hot water treatment, respectively. The highest value of WAC and OAC was observed for microwave-treated RC and hot water-treated RR, respectively. WAC increases with both treatments, whereas OAC increases only with water bath cooking. Functional group analysis (FTIR) showed no major peaks shifting in water bath treatment, whereas a slight deflation of certain peaks was observed in the case of microwave treatment. Pasting curves showed a significant reduction in peak and final viscosity after pre-gelatinization treatment; however, none of the samples showed any breakdown during cooking. Graphical Abstract: (Figure presented.)