White kiwis peel like bananas and have a higher vitamin C content

'White' kiwis (Actinidia eriantha Benth.) are a new cultivar that was registered in China and that have a higher L-ascorbic acid (AsA - between 5.69 and 11.37 g/kg of fresh weight) compared to other cultivars. L-ascorbic acid is commonly known as vitamin C.

White kiwis could be popular for their high grades, nice flavour and for the fact they peel like bananas!

Researchers from the Zhejiang Gongshang University in Hangzhou (China) analysed changes in AsA, related metabolites, enzymatic activity and the gene expression associated with Asa biosynthesis and recycling process. Results showed that Asa biosynthesis through L-galactose pathway supplemented by D-galacturonic acid pathway and Asa recycling collectively contributed to accumulating and maintaining a higher Asa level in the White cv during the post-harvesting phase.

In addition, L-galactose dehydrogenase (GalDH) activity and the relative expressions of the genes that encode GDP-D-mannose pyrophosphorylase (GGP), GaIDH and D-galacturonate reductase (GaIUR) were important to regulate AsA biosynthesis. The activity and expression of dehydroascorbate reductase (DHAR) were primarily responsible for AsA recycling in White kiwis during post-harvesting.

These genes could be suitable for the nursing and selection of new cultivars with a higher Asa content during post-harvesting until over-ripening.

Source: Zhen-Ye Jiang, Yu Zhong, Jian Zheng, Maratab Ali, Guo-Dong Liu, Xiao-Lin Zheng, 'L-ascorbic acid metabolism in an ascorbate-rich kiwifruit (Actinidia. Eriantha Benth.) cv. 'White' during postharvest', 2018, Plant Physiology and Biochemistry.