Abstract: To investigate the effect of hydrocolloid combined with microwave treatment on the retrogradation properties of corn starch, this study analyzed the effects of three hydrophilic colloids (konjac gum, guar gum, and gum arabic) on the textural properties, retrogradation enthalpy, moisture distribution, in vitro digestibility, short-range ordered structure, and crystal structure of retrograded samples. The results indicated that hydrocolloid combined with microwave treatment significantly reduced the retrogradation enthalpy and relaxation time, reflecting reduced starch recrystallisation. Compared with the untreated control group, konjac gum combined with microwave treatment exhibited the most pronounced inhibitory effect; the retrogradation enthalpy of retrograded samples decreased to 2.03 J/g after storage at 4 ℃ for 14 days. Additionally, both short-range order and crystallinity decreased significantly in the treated group (P < 0.05), indicating that the combined treatment effectively suppressed starch retrogradation. It markedly reduced the in vitro digestibility of retrograded samples. Compared with the control group, the rapidly digestible starch content in the guar gum + microwave-treated group after 14 days of storage decreased from 59.28% to 32.54%, while the resistant starch content significantly increased from 15.69% to 37.44% (P < 0.05). These findings indicate that hydrocolloid combined with microwave treatment enhances the interactions between hydrophilic colloids and starch, inhibits starch retrogradation, and improves its digestive properties. This research provides an effective approach for developing starch-based materials with favorable textural stability and low digestibility characteristics.

Key words: corn starch; hydrocolloids; microwave treatment; retrogradation characteristics; in vitro digestibility