摘要 : Depolymerizing effects of soy proteins on gluten networks in mixed wheat-soy dough were studied during dough mixing and resting. Mixed dough was prepared by replacing wheat flour with enzyme-active soy meal, enzyme-inactive soy me... 展开 Depolymerizing effects of soy proteins on gluten networks in mixed wheat-soy dough were studied during dough mixing and resting. Mixed dough was prepared by replacing wheat flour with enzyme-active soy meal, enzyme-inactive soy meal or soy protein isolate at 6, 5 and 3%, respectively, and the influence of this substitution on protein composition and contents of glutenin macropolymer and free sulfhydryl groups was determined. Protein from active soy meal decreased glutenin macropolymer content as a result of gluten depolymerization, whereas inactive soy meal increased glutenin macropolymer content of the composite flour and dough due to loss of soy protein solubility leading to coprecipitation with glutenin macropolymer. Soy protein isolate did not change glutenin macropolymer content but increased free sulfhydryl content during dough resting. Multistacking SDS-PAGE analysis demonstrated changes to protein profiles due to soy addition. Soy proteins were extracted along with gluten in SDS buffer and remained associated to insoluble wheat proteins in the resulting gluten fraction. It is concluded that soy proteins cause adverse effects on the gluten network and become associated with wheat protein via physical interaction and covalent and non-covalent bonds during dough mixing and resting; large and medium-sized polymers, which form as a result of interaction, increase SDS solubility of gluten proteins, resulting in network weakening. 收起