Structural-state-dependent effects of RVA-treated waxy starch on multiscale evolution and freeze-thaw resistance of...

Physically modulating the structural state of waxy starch offers a clean-label strategy to improve the freeze-thaw (FT) tolerance of high-fat myofibrillar protein (MP) emulsion gels. In this study, waxy corn starches with distinct structural states, including native crystalline starch (NCS), partially disordered starches with gelatinization degrees of 45% (PDS45) and 70% (PDS70), and amorphous starch (AS), were prepared by thermal-shear treatment. These starches were incorporated into MP emulsions to elucidate their roles during emulsification, thermal gelation, and FT storage. During emulsification, the transition from crystalline granules to disordered fragments and accessible chains promoted starch-MP redistribution at oil-water interfaces, and increased interfacial thickness. During thermal gelation, PDS45 and PDS70 retained sufficient chain integrity and mobility, thereby promoting interfacial-matrix integration and strengthening starch-MP networks. After FT cycles, the PDS45-MP gel exhibited the greatest structural stability among all gels, as evidenced by higher springiness, lower thawing loss, reduced water/lipid migration, and better retention of MP conformation. Conversely, the AS-MP gel formed irregular aggregates with insufficient bulk network support, resulting in the poorest FT stability. The NCS-MP gel showed thin interfacial layers, a loosely organized network, and stronger starch retrogradation, resulting in dehydration, droplet coagulation, and higher hardness after thawing. Thus, partially disordered starch, rather than fully amorphous starch, better coordinated interfacial assembly, gel formation, and FT stability in MP emulsions, providing guidance for designing restructured frozen protein products.