The key metabolite of fruit flavor change in different ripening stages of .

has an unstable ripening period. Herein, five typical periods of fruit ripening of 'LR' were analyzed by non-targeted metabolomics techniques. The results showed that ripening started 73 days after flowering and reached the ripening criterion at 93 days, a total of 451 differential metabolites were identified for the five periods. KEGG enrichment pathway showed that significant changes in citric acid were significantly correlated with changes in the downstream substance spermine (  = 0.9068,  = -5.49 + 0.66×), while citric acid (  = 0.9982) and spermine (  = 0.9841) were negatively correlated with the sugar-acid ratio. Citric acid was the main component of titratable acid and spermine (  = 0.9991) was positively correlated with titratable acid. We speculated that citric acid is a key taste marker for fruit ripening in 'LR' . The results of the study provide new metabolic evidence for flavor changes and scientific basis for their quality improvement and exploitation in .