Investigate The Impact of Ultrasound-Assisted Soaking Pretreatment On the Extraction Yield and Quality of Rice Bean Protein

Abstract

The increasing demand for sustainable high-quality plant protein sources has driven the need for developing sustainable food items. Rice bean (Vigna umbellata) is an underutilized plant-based legume and recognized with promising nutritional potential, rich in protein content with essential amino acids. However, presence of antinutritional factors, dense structure, and more soaking time hinders the functionality, digestibility, and quality of protein. This study investigates the use of ultrasound-assisted treatment as a pretreatment for the extraction and quality evaluation of rice bean protein. Here, ultrasound waves of 25 to 75 kHz for 10 to 30 min time duration were used for the soaking of rice bean and subsequently extracted protein using conventional method. This process significantly (p<0.05) reduced the soaking time, antinutritional (ANF) factors (tannin, phytic acid, saponin, and trypsin inhibitors), and improved the protein quality. Moreover, the extracted protein exhibited the improvement of water holding capacity, oil holding capacity, emulsifying capacity, foaming capacity, solubility, and digestible properties. Additionally, scanning electron microscopy (SEM) and FTIR analysis showed cellular rupture and improvement in structural properties. Similarly, rheological and gelling properties were also improved up-to the ultrasound amplitude of 50 kHz and 20 min. However, excessive ultrasound amplitude and time decreased the quality of protein. Therefore, ultrasound-assisted soaking as a non-thermal, environmental-friendly promising technique to enhance the extraction yield and recover high quality protein from underutilized rice bean. This approach offers a significant value in the formulation of sustainable, health-oriented, and functional ingredients for the development of food products for a growing plant-based market.