Differential impacts of endogenous lipid change on rice quality during storage

This study investigated the degradation of endogenous lipids in brown rice (BR) and polished rice (PR) during two years of storage and its impact on quality. The total lipid content decreased in both, with greater non-starch lipid loss in BR. Lipid oxidation–related enzymes (LA, LOX, POD, CAT) declined more rapidly in BR, while oxidation products (FAV, POV, CV, MDA) continuously accumulated. Lipid degradation affected starch structure, increasing amylose content, short-range order, and double-helix formation. 2D-COS-FTIR revealed that BR was more sensitive at 1147 cm -1 , while PR was more sensitive at 995 cm -1 , and changes in amorphous regions occurred earlier than in crystalline regions. BR showed higher hardness and G′, while PR lost elasticity and adhesiveness. Both exhibited decreased gelatinization temperatures and viscosities. GC–MS identified 72 volatile compounds, with aldehydes such as hexanal significantly increased in BR, and differential markers affected by storage were identified in BR and PR. • Non-starch lipids in BR degraded rapidly, promoting oxidation and flavor formation. • 2D-COS clearly revealed effects of starch lipids on starch structure and retrogradation. • Deterioration was primarily driven by enzymatic oxidation in BR, but non-enzymatic oxidation in PR. • GC-MS identified 72 volatiles, with aldehydes increasing during storage.