Study on the Effect of Protein Complex of Textured Soy Protein and Soy Protein Hydrolysate on Noodle Quality and Dough Rheological Properties

In order to improve the nutrition quality of flour products and reduce the weakening effect of soy protein hydrolyzates (SPH) on the gluten network, the complex of the texturized soy protein (TSP) and the SPH with a degree of hydrolysis of 7.57% (SPH) was added to the wheat flour (the substituted amounts of TSP and SPH for flour were 5.7% and 2.4%, respectively). The gluten characteristics, farinographic characteristics, rheological properties and noodle quality were compared. The results showed that, when TSP/SPH was added into flour, no gluten was formed, and the dough’s stability time decreased and weakening degree increased. The dough’s G′ and G″decreased, and the loss factor and the viscosity ratio both increased. The contents of gluteninmacropolymer and disulfide bond increased.Compared with the wheat flour noodles, the hardness and the elasticity of the noodles decreased from 3 075.02 g and 0.83 to 2 744.94 g and 0.76, respectively; and the texture characteristics and the cooking quality of the noodles both deteriorated.Overall, TSP/SPH interfered with the formation of the gluten network through the interaction of disulfide bonds with gluten, which resulted in the deterioration of gluten characteristics and the farinographic properties of the flour, the increase of the viscosity ratio of the dough, and the decrease of the quality of the noodles.