Abstract: Post-harvest plum fruits (Prunus salicina cv. Black amber) were treated with 1-methylcyclopropene (1-MCP) and then stored at 0 ℃ for 28, 67 or 96 d before shelf-life storage for 9 d at 20 ℃ to deal with the effect of 1-MCP on non-volatile components in plum during cold storage and subsequent shelf life was investigated using multivariate analysis. One-way analysis of variance (one way-ANOVA) showed that the levels of sucrose and malic acid decreased gradually, D-fructose level decreased at first and then increased in plum fruit during cold storage, whereas the peaks of other components productions were detected on day 67 of cold storage. In contrast, non-volatiles in plum fruit reached their peaks on at the end of the shelf life after 96 d of cold storage. Principal component analysis (PCA) showed that the contents of various components in plum fruits stored for 67 d at 0 ℃ decreased at the end of the shelf life compared with those at the beginning, while plum fruits after 96 d of storage at 0 ℃ showed an opposite change during the subsequent shelf-life storage. Because of 1-MCP treatment, the peaks of sugars and acids in plum fruits stored for 67 d and for 96 d significantly dropped during the shelf life, and the metabolic rates of these substances slowed down, the nutritional quality was maintained, and fruit deterioration was delayed. Partial least squares regression (PLSR) and path analysis showed that D-fructose was significantly and positively correlated with sensory sweetness/sourness ratio, and was a major direct or indirect factor. Malic acid correlated significantly and positively with sensory sourness or soluble solids content (SSC), while D-glucose had an indirect impact on SSC. Sorbitol was significantly and negatively correlated with pH value.

Key words: plum, 1-MCP, sugar, organic acid, amino acid, multivariate analysis