Optimization of rice bean cooking parameters for the production of instant/convenience foods using response surface methodology

Abstract

An optimized cooking protocol (OCP) for rice bean (Vigna umbellata) was developed to improve the efficiency of the conventional process (CP) which limits the exploration of rice bean for commercial applications. The cooking process was studied to achieve optimum processing time, least grain breakage, minimum solid loss (SL), and best overall acceptability (OAA). A central composite rotatable design was used to evaluate the effect of process variables, namely soaking time (STi: 3–12 hr), soaking temperature (STe: 30–60 °C), and cooking time (CT: 12–32 min) on process responses. The optimized process conditions were: STi of 7 hr, STe of 42 °C, and CT of 22 min that reduce the STi (12 hr), CT (35 min) and SL (22.5%) of the CP by 42, 37, and 52%, respectively. The grains from OCP had significantly (p < .05) better physico-nutritional (grain surface area: 159.52 ± 12 mm2, calcium: 156 ± 3.11 mg/100 g, antioxidant activity: 335 ± 43 μM butylated hydroxyanisole/100 g) properties and similar OAA (8.55). The OCP is highly suitable for rice bean intended for developing instant foods. Practical applications The cooked grains can easily be obtained from conventional process but certain constraints associated with it which limits its applicability for commercial production of rice bean based instant/convenience foods products. These constraints include susceptibility of cooked grains to breakage, necessity of immediate downstream processing to prevent germination or spoilage, and long processing time (soaking time: 12 hr, cooking time: 30–35 min) as well as high leaching loss of solid (22–28.55%). The optimized process conditions are able to reduce the soaking time (12 hr), cooking time (35 min), and solid loss (22.5%) of conventional process by 42, 37, and 52%, respectively. The information of this article will be useful for the industrialists associated with commercial production of ready-to-eat (RTE) bean products, baked bean, and instant bean products.