Functional Additives Enhance Freeze–Thaw Stability and Retard Retrogradation in Wheat–Potato Starch Gels and Crystal Dumpling Wrappers

Crystal dumpling wrapper production is hampered by rapid surface dehydration, severe freeze-cracking propensity, and storage-induced retrogradation. Modulation of blended starch properties through functional additives was investigated. This study systematically evaluated the impact of hydroxypropyl distarch phosphate (HPDSP), trehalose (TRE), guar gum (GG), and composite phosphates (CP) on physicochemical and structural properties of wheat-potato starch composite gel. Concurrently, the effects of additives on the cracking rate of crystal dumplings and texture of wrappers were investigated. Analysis revealed that apparent viscosity was increased by all additives except CP. Different additives significantly improved the freeze-thaw stability of the composite gel during the first three cycles. GG maintained enhanced freeze-thaw stability throughout the entire freeze-thaw cycle (dehydration shrinkage rate: 2.69-40.55%). Multivariate analytical techniques (SEM, FTIR, XRD, DSC) collectively indicated that the additives effectively inhibited starch retrogradation, whilst HPDSP showed the strongest retrogradation inhibition. CP enhanced water-retention capacity and produced a softer blended gel (hardness at 21 days was 100.56 gf). Furthermore, additives significantly reduced the freezing cracking rate of crystal dumplings and improved the textural properties of dumpling wrappers.