Comparative study of texture, gelatinization, retrogradation, structure, and digestibility in starch-hydrocolloid composites: Effects of frozen and unfrozen treatments

Hydrocolloids are widely used as functional additives to improve the quality attributes of frozen wheat-based products. This study systematically examined the effects of carrageenan (CGN), xanthan gum (XG), carboxymethylcellulose (CMC), sodium alginate (SA), curdlan (CL), hydroxypropylmethylcellulose (HPMC), guar gum (GG), konjac glucomannan (KGM), and gelatin (Gel), each at 1.5 % (w/w, starch basis), on the solubility, swelling power, pasting properties, light transmittance, retrogradation behavior, syneresis, textural attributes, crystalline structure, viscoelasticity, and in vitro digestibility of both unfrozen and frozen starch. The results showed that hydrocolloids significantly modified starch functionality. In particular, they reduced syneresis, delayed retrogradation, and decreased hardness, while enhancing light transmittance and viscoelastic performance. SA, CGN, KGM, and XG notably suppressed relative crystallinity by inhibiting amylose recrystallization, with SA, KGM, and XG producing the strongest effects—reductions of 64.67 %, 66.24 %, and 43.73 %, respectively, compared with the frozen control. Moreover, KGM, XG, and SA markedly altered starch granule morphology and significantly reduced rapidly digestible starch content during freezing, with reductions of 11.32 %, 10.61 %, and 8.44 %, respectively, compared with the control. Overall, these findings highlight XG, KGM, and SA as particularly effective in controlling starch retrogradation and modulating digestibility in both unfrozen and frozen starch, offering valuable guidance for the development of improved starch-based food products.