Optimization of extraction process for legume-based synbiotic beverages, followed by their characterization and impact on antinutrients

Abstract

The study aims to optimize the extraction conditions for legume-based synbiotic beverages from kidney beans (Phaseolus vulgaris L.) and mung beans (Vigna radiata L.) using response surface methodology (RSM). The variables considered were NaHCO3 concentration (X1: 0.01–0.1% w/v), time (X2: 5–15 min), and temperature (X3: 80–100 °C). The quadratic models for the responses viz. prebiotic content, beverage yield, total phenol content, and antinutrients were the best fit (R2 > 0.9). The optimized condition for red kidney bean beverage (RKB) suggested that employing extraction at 89 °C for 12.3 min using 0.01% NaHCO3 would lead to the maximum prebiotic content, beverage yield, and total phenol content along with reduced antinutrients. Similarly, extraction at 100 °C for 11 min using 0.08% NaHCO3 for green mung bean beverage (GMB) was the final optimized condition. After the fermentation with probiotic bacteria, Lactobacillus casei, the antinutrients in RKB, i.e., phytate, tannin, and saponin, were reduced by 29%, 58%, and 28%, while prebiotic content was reduced to 71%. Likewise, phytate and saponin in GMB showed a reduction of 49% and 45% after probiotic fermentation and a 67% reduction in prebiotic content. The beverages extracted at the optimum condition had good physio-chemical properties and sensory acceptance (OA of 6 out of 9).