Effects of additives on the frozen storage quality of frozen crystal dumplings wrappers: Hydroxypropyl distarch phosphate, trehalose, guar gum, and composite phosphate

Crystal dumplings are susceptible to quality deterioration during frozen storage, exhibiting textural hardening, loss of springiness, and reduced water retention due to starch retrogradation and ice crystal damage. This study aimed to systematically investigate the effects of hydroxypropyl distarch phosphate (HPDSP), trehalose (TRE), guar gum (GG), and composite phosphate (CP) on the quality and structural properties of frozen crystal dumpling wrappers (FCDW) during long-term frozen storage (−18 °C, 60 days) and elucidate potential mechanisms. The results demonstrated that the additives delayed the increase in hardness (reduced from 38,339.26 g to 31,408.86 g on day 60) and the decrease in springiness of FCDW. The additives reduced the freezable water content of FCDW. Notably, HPDSP and GG decreased the proportion of free water, thereby significantly improving the freezing stability of FCDW. Additionally, additives suppressed the continuous increase in contact angle and delayed starch retrogradation. Additives reduced the gelatinization enthalpy of FCDW and inhibited the increase in particle size to some extent. Multiple analytical techniques (SEM, FTIR, XRD) indicated that additives reduced the short-range ordered structure and relative crystallinity of FCDW, with HPDSP exhibiting the most pronounced effect. In conclusion, additives improved the quality deterioration of FCDW by reducing water migration, providing freeze protection, and delaying starch retrogradation.