ISHS Acta Horticulturae 553: IV International Conference on Postharvest Science
LIGHT AND TEMPERATURE AFFECT POSTHARVEST COLOUR DEVELOPMENT IN ‘CRIPPS’ PINK’ APPLES |
| Authors: | E. Marais, G. Jacobs, D.M. Holcroft |
| Keywords: | anthocyanin, red blush, Malus x domestica Borkh., Pink Lady™ |
| Abstract:
Since postharvest irradiation can enhance blush development in apples this system was used to understand the interactions between light and temperature on anthocyanin synthesis. ‘Cripps’ Pink’ apples harvested from two growing regions, Grabouw and Ceres, were subjected to 120 h of irradiation at 6°C or 20°C following 0, 2 or 5 days at -0.5°C. Fruit harvested from Grabouw were consistently redder when irradiated at 6°C than 20°C, although there was slight improvement in colour after storage at -0.5°C for 5 days prior to irradiation. Fruit harvested from Ceres and irradiated immediately showed increased anthocyanin synthesis at 6°C compared to 20°C. The difference between the temperatures was no longer significant after fruit had been stored for 5 days prior to irradiation. In a second experiment, fruit were stored for 20 days at -0.5°C prior to irradiation at either 6°C or 20°/6°C (day/night). The fluctuating temperature resulted in better colour and higher anthocyanin concentrations for fruit from both areas. The hue angle of well-coloured ‘Cripps’ Pink’ apples irradiated at 37°C increased from 29° to 48° and the anthocyanin concentration decreased from 740 ug·g-1 to 284 ug·g-1 after 144 h of irradiation. Fruit held at 37°C in the dark did not show any loss of red colour or anthocyanin degradation. | |
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