Cluster analysis of Japanese plum cultivars for optimizing export handling conditions

Cold storage is the most popular method used to retain fruit quality during shipping. However, cold storage can affect the fruit quality of plum cultivars differently. This study aimed to identify the cultivars with similar responses to reduce quality loss. The physical, biochemical, and physiological responses of twelve plum cultivars stored under simulated commercial conditions were analyzed. Results showed significant differences in physiological and physicochemical properties between cultivars, including total soluble solids (ranging from 13 ± 0.4% to 16.53 ± 0.35% at harvest), TSS/TA (7.03 ± 0.47 to 18.19 ± 1.56 at harvest) and color (9.48 ± 0.71 to 68.43 ± 0.74 at the end of shelf life). Two physiological groups of plum cultivars were identified: climacteric and suppressed-climacteric plums. PCA highlighted firmness, color, respiration, TSS/TA ratio, and BrimA as the main features for distinguishing plum cultivars. Also, although the K-means model presented better-defined clusters (silhouette score of 0.45±0.06), hierarchical clustering (silhouette score of 0.22±0.02) can offer different options depending on related constraints, via hierarchical relationships among clusters. This study serves as a guideline for industrials to improve storage conditions and minimize quality loss during export for long-distance destinations.