Effects of freeze–thaw cycles on the physicochemical and in vitro digestibility of starch in pre‐fermented frozen raw dough

Summary In this study, pre‐fermented frozen raw dough (PFRD) was subjected to freeze–thaw cycling (FTC) to explore the deterioration mechanism of PFRD, after which the physical quality, chemical properties and in vitro digestion characteristics of starch in the dough were analysed. The results showed that after the 5th FTC, the surface area of the dough and starch exhibited obvious depression deformation, and the damaged starch content increased by 38.21%. The random mechanical damage caused by ice crystals also had no significant regularity in the water retention and the short‐range order of starch. Moreover, the breakdown of the double helix structure of starch led to the dissolution of amylose, and the expansion and gelatinization enthalpy increased. In addition, the in vitro digestion results showed that freeze–thaw cycle twice increased the digestibility of the starch, and the hydrolysis rate reached 75.16%, Therefore, the effects of FTC twice on the starch of PFRD are controllable. This study provides a theoretical basis for the development of prefabricated frozen starch food industry technology in the future.