Quantitative evaluation of storage tolerance in the eating and cooking quality of rice varieties from southern China

▪ A novel index (PRSI) was developed to quantitatively assess the storage tolerance of rice eating quality. ▪ High storage tolerance in rice varieties is strongly associated with retained antioxidant enzyme activities. ▪ A predictive model enables rapid and efficient screening of storage-tolerant rice varieties in southern rice-growing regions. This study aimed to characterize variation in the storage tolerance of eating and cooking quality (ECQ) among rice varieties from Southern China and to establish a quantitative evaluation framework. Indica , japonica , and indica – japonica hybrid rice varieties were subjected to accelerated aging under high-temperature and high-humidity conditions (35°C, 75% RH) for 90 days. Nineteen indices encompassing ECQ traits, chemical composition, pasting properties, amylase activity, lipoxygenase (LOX) activity, and antioxidant enzyme activities were determined before and after storage. The storage variation coefficient of individual indices (SVCI) and a newly developed paddy rice storage tolerance index (PRSI) were used for integrated evaluation. Principal component analysis, grey relational analysis, and stepwise regression analysis were applied to identify key indicators and construct a predictive model. ECQ deteriorated significantly after storage, with pronounced changes (mean SVCI>0.2) observed in fatty acid value (FAV), cooked rice appearance (CRA), cooked rice texture (CRT), comprehensive taste value (CTV), and antioxidant enzyme activities. PRSI values ranged from 0.257 to 0.609, with higher PRSI values indicating more rapid ECQ deterioration during storage. Cluster analysis classified the varieties into storage-tolerant, moderately storage-tolerant, and storage-sensitive groups. Compared with storage-sensitive varieties, storage-tolerant varieties showed markedly smaller declines in CRA, CRT, and CTV (mean reductions lower by 45.8, 40.9, and 49.3%, respectively), a weaker increase in FAV (mean lower by 28.3%), and consistently higher antioxidant enzyme activities, with SOD and POD activities exceeding those of storage-sensitive varieties by 19.7 and 10.0%, respectively, in both fresh and stored samples. These results demonstrate that PRSI is an effective index for evaluating ECQ storage tolerance. The SVCIs of CTV, FAV, and POD activity were identified as key predictors of PRSI. This work provides a robust methodological basis for breeding storage-tolerant rice varieties and for developing quality-preserving storage strategies in southern rice-growing regions.