Effect of postharvest storage temperature on antioxidants of South African golden kiwifruit

The extension of the storage life of kiwifruit is achieved by low temperature control. Phytochemical compounds are a large constituent of kiwifruit quality and are affected by numerous pre- and postharvest factors, especially storage temperature. The monitoring and control of storage temperature are important to maintain these compounds. There is very little published information on cold storage temperature for optimum quality for South African kiwifruit cultivars during long-term storage. This study investigated the effect of different cold storage temperatures (0 and 2°C) on phytochemical compounds (phenolic content, antioxidant capacity and ascorbic acid content) of ‘Soreli’ and ‘Skelton’ kiwifruit. Two cultivars (‘Soreli’ and ‘Skelton’) were harvested from an orchard in White River (Mpumalanga), South Africa. Each harvest consisted of 100 fruits, and each cultivar was packed into boxes, with 4 replications each. Fruit were stored at 0 and 2°C for 2 months and left to ambient conditions for seven days for shelf life study. Sampling occurred after harvest, cold storage and shelf life for antioxidant capacity, ascorbic acid concentration, total phenolic content, and total soluble solids content. The experimental design used was a randomised complete design (RCD). Cold storage had a significant effect on both ‘Skelton’ and ‘Soreli’. After cold storage at 0°C, the fruit showed increased antioxidant capacity and total phenolic compounds for both ‘Skelton’ and ‘Soreli’ than fruit stored at 2°C. Ascorbic acid concentration decreased significantly after shelf life at both 0 and 2°C for ‘Soreli’. Mid-maturity harvested fruit stored at 0°C resulted in improved fruit quality and optimum conditions for preserving biochemical quality attributes.