Elevating the critical gelling concentration of soy protein by disulfide bond cleavage during preheating treatment

Abstract

There has been a growing demand for the development of high protein beverages in the food industry. However, during thermal processing, high-protein beverages undergo protein aggregation and gelation. In this study, thermostable soy protein was prepared by disulfide bond cleavage combined with preheating treatment. Thermostable soy protein had a higher denature extent than the control sample, which prevented the formation of larger aggregates upon reheating. Thermostable soy protein possessed lower viscosity (nearly 0 Pa·s) and an excellent fluidity index (around 0.8) after reheating at a concentration of 10 % (w/v), whereas the control sample had gelled. Moreover, rheology and dynamic light scattering collectively demonstrated that a minimum of 2.5 mM sodium metabisulfite (Na₂S₂O₅) was required to prepare thermostable protein solutions. The present study shows an innovative method to produce thermostable soy protein.

Keywords: Disulfide bond cleavage; Preheating; Sodium metabisulfite; Soy protein particles; Thermal stability.