Adsorption behavior of soybean protein isolate-soyasaponins mixed system at saliva interface and influence mechanism of saponin bitterness presentation

The bitterness of soyasaponins (Ssa) is one of the main causes of undesirable flavors in soy products. In this study, a Ssa-soybean protein isolate (SPI) binary system was constructed to simulate the adsorption behavior of soybean products at the oral-salivary interface and the mechanism of bitter taste development was investigated. The concentration of Ssa with was determined to be the minimum bitterness value approximately 0.5 mg/mL by sensory evaluation and electronic tongue determination. The nonspecific interactions were confirmed by isothermal titration calorimetry (ITC) and endogenous fluorescence measurements. Ssa formed aggregates with SPI that desorbed from the interface into the bulk phase, resulting in a subsequent increase in particle size and turbidity. This study demonstrated the ability of SPI with Ssa at specific concentrations to attenuate the bitter flavor of Ssa, thus providing important implications for increasing the acceptability of soy products.