Investigation on Early Softening of Kiwi Fruit

Abstract

Early softening is the main problem for the exports of Chilean kiwi fruit. It has been related to orchard condition and to harvest and postharvest handling. In this investigation, experiments were carried out to test the influence of growing conditions and some fruit characteristics on the softening rate of kiwi fruit, from different orchard in the central zone of Chile. Fruits from all orchards were harvested at 6.2-6.5 soluble solid content, and kept under the same storage condition (0°C, regular air). Samples were taken every fifteen days to determine softening index (S.I.), which was calculated by the initial firmness minus final firmness, divided by the days till the fruit reached 20 N of firmness. There was a large variation in S.I. between orchards and also in the same orchard. The fruit characteristics assayed were size, position and illumination of fruit in the plant. For this purpose fruit from the same plants were harvested and tested in the same way as described before. The influence of size on early softening was found in 3 of the 4 orchards tested, having the larger fruit the lowest firmness loss. The position on the fruit on the plant (distance from the base of the cane) had no clear influence on fruit firmness. The fruit from better illuminated part of the plant had higher initial firmness, but also higher firmness loss during storage, nevertheless the final firmness was higher in the better-illuminated fruit.