Heat-pretreatment and enzymolysis behavior of the lotus seed protein

Lotus seed protein (LSP) was heat-pretreated before enzymolysis in order to seek a greater degree of hydrolysis (DH) during enzymatic hydrolysis. The parameters including substrate concentration, temperature, pH, and papain concentration were optimized by response surface methodology in the enzymolysis of the heat-pretreated LSP. The influence of substrate concentration on the non-pretreated LSP enzymolysis was assessed, and the enzymolysis was found to obey the Haldane model with inhibition by LSP substrate. The initial concentration of non-pretreated LSP was inferred theoretically to be 11.07 g/L in order to avoid substrate inhibition. On the other hand, Chrastil model was fitted and the diffusion resistance constant values were in the range of 0.5-0.6 for the diffusion-controlled encounter of enzyme and substrate, implying that diffusion was a rate-limiting step. The heat-pretreatment at 60 °C for 60 min could increase the DH of the LSP, which enhanced the efficiency of the enzymolysis by papain.