Sugar composition, total phenolic content, and radical scavenging activity of 12 Japanese plum cultivars grown in South Africa: from harvest to shelf life

This study investigated the cultivar-dependent variation of metabolites in 12 plum cultivars grown in South Africa. Individual sugars, total phenolic content (TPC) and radical scavenging activity (RSA) were investigated in fruit at harvest and end of shelf life. Individual sugars were profiled using gas chromatography, while TPC and RSA were measured at harvest and shelf life. Sugar profiling revealed variations in cultivars, depending on the fruit handling stage. Total sugars ranged from 46.35 to 148.99 g kg^-1 dry weight (DW) at harvest and 54.43 to 125.10 g kg^-1 DW at shelf life. ‘Angeleno’ had the highest sorbitol content regardless of fruit handling stages. Higher TPC was found in the peel than the flesh at both handling stages in all investigated cultivars. Total phenolic content ranged from 104.18 to 173.55 mg GAE g^-1 DW at harvest and 151.85 to 183.23 mg GAE g^-1 DW at shelf life. ‘Green Red’ had the highest TPC and RSA, suggesting polyphenols contributed to the antioxidant power of the fruit cultivar. Overall, this study provides valuable information that can be useful for cultivar selection for fresh consumption and industrial application, enabling the development of postharvest handling for the investigated plum cultivars.