Inhibition of moisture migration and lipid oxidation in fermented rice cakes by carboxymethyl chitosan

Traditional fermented rice cakes (FRC) experience rapid quality deterioration during storage due to moisture migration and lipid oxidation, reducing shelf life and consumer acceptability. This study investigated carboxymethyl chitosan (CMC) dual preservation mechanisms on FRCs during storage. FRCs with varying CMC concentrations (0-0.5 g/100 g) were evaluated during the 15-day storage at 4°C using multiple analytical techniques. Optimal 0.3 g/100 g CMC addition reduced hardness from 14.19N to 12.24N, improved springiness by 12.3mm. Low-field NMR revealed that CMC effectively restricted water mobility, FTIR confirmed hydrogen bond network formation between CMC and starch. XRD analysis showed CMC reduced relative crystallinity from 34% to 28%, indicating inhibited starch retrogradation. HS-SPME-GC-MS analysis revealed that CMC treatment reduced oxidation-related volatile compounds, with acetaldehyde decreasing by 1.32%, while heptanal and n-valeric acid both decreased by 3.05%. UPLC-MS profiling revealed 432 lipid species with 22 significantly different lipids demonstrating enhanced protection. CMC preservation mechanisms involve competitive hydrogen bonding with water mole clues, inhibiting starch chain realignment and preventing retrogradation while providing antioxidant protection through radical scavenging. This study represents the first systematic investigation of CMC effects on lipid oxidation and moisture retention in traditional FRCs, demonstrating its dual-action preservative mechanism for maintaining quality attributes of FRC. • CMC at 0.3 g/100 g provides dual preservation via moisture retention and lipid protection. • CMC forms hydrogen bonds with starch, reducing crystallinity and stabilizing water. • CMC significantly reduced oxidation compounds including acetaldehyde and heptanal.