Soy protein isolate improves the structure, starch retrogradation and water distribution of a Chinese traditional rice/bean food Dousi: towards high low‐temperature storage stability

Fresh wet Dousi (FWD) is a traditional Chinese food made from rice and beans through wet milling and dry heating. However, its drawback of storage stability at low temperatures (4 °C) challenges the market development. Thus, soy protein isolate (SPI) was incorporated to improve its structure, starch retrogradation and water distribution. SPI reduced FWD's peak viscosity, trough viscosity, final viscosity and setback values. Additionally, the hardness, retrogradation enthalpies (ΔH), crystallinity and infrared absorbance ratio at 1047/1022 cm −1 and 995/1022 cm −1 of FWD decreased significantly after adding SPI. From the rheological, LF‐NMR and SEM results, SPI was favourable to the formation of porous and flexible structure within FWD. The variation of food structure improved the binding ability of starch or other components with water. This work indicated that SPI could improve the low‐temperature stability of FWD by enhancing the water capability, inhibiting the starch retrogradation, and promoting structural compliance within the network.