Temperature-associated quality deterioration and fungal community succession in stored paddy rice during long-term...

Storage temperature critically governs physicochemical deterioration and fungal community succession in paddy rice. This study examined quality changes and fungal dynamics in three Yongyou-series hybrid rice varieties stored for 240 days at 15 °C and 25 °C. Fatty acid value (FAV), malondialdehyde (MDA), and electrical conductivity increased progressively, while polyphenol oxidase activity and soluble albumin and globulin contents declined; all changes were more pronounced at 25 °C, indicating accelerated lipid oxidation, membrane damage, and protein structural alteration. ITS amplicon sequencing revealed a gradual shift from field-associated toward storage-adapted fungal taxa. At 25 °C, potentially risk-associated genera-including Aspergillus, Wallemia, and Curvularia-increased markedly during late storage, whereas 15 °C storage promoted slower community restructuring. Exploratory correlation analysis identified co-variation between selected fungal taxa and FAV, MDA, and electrical conductivity; however, as these correlations were not adjusted for storage duration, they may partly reflect shared temporal trends rather than independent associations. Overall, 15 °C storage delayed quality deterioration and attenuated the relative enrichment of risk-associated taxa, supporting low-temperature storage as a potential strategy for storage-risk management.