EFFECTS OF LIGHT AND TEMPERATURE ON COLOUR CHANGES IN RIPENING FRUIT OF ACTINIDIA MACROSPERMA

Unripe, green fruit of Actinidia macrosperma turn an intense orange during ripening on the vine or after harvest. The change in colour is due to degradation of chlorophyll and synthesis of carotenoids. Temperature and light can influence the rate of colour change during storage of the fruit. Fruit harvested green and then stored at room temperature (c. 20°C) quickly turned a bright orange colour, irrespective of light regime. Green fruit stored at 4°C did not turn orange but instead became white or pale yellow over a period of 10 weeks. If these fruit were then shifted to room temperature, they rapidly turned bright orange. Changes in fruit colour during storage appear to be affected more by temperature than by light. It is concluded that carotenoid biosynthesis is more strongly affected by temperature than is chlorophyll degradation