Effects of soy protein isolates and transglutaminase addition on the structure, physicochemical properties, and oil absorption of wheat flour

The effects of soy protein isolate (SPI) addition and transglutaminase (TG) treatment (SPI-TG) on the microstructure, physicochemical properties, and oil absorption of wheat flour were studied. After the SPI-TG treatment, the disulfide bonds increased to 1.9657 mu mol/g. SPI-TG (30 U/g) significantly promoted the transformation of the secondary structure of protein from beta-turns and random coils to beta-sheets. In addition, electrophoretograms showed that there was a decrease in smaller molecular weight peptides and an increase in protein aggregates, which was consistent with the change in scanning electron microscopy. The thermal stability, viscosity and oil content of the SPI-TG treatment wheat flour were influenced by the degree of protein crosslinking. The changes in the structure and properties of wheat flour induced by SPI-TG treatment were beneficial to reducing the oil absorption of fried flour. This provided theoretical guidance for targeted modification of fried food ingredients, facilitating the development of healthy, low-fat fried foods.