ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Colour response of Cripps Pink apples to postharvest irradiation is influenced by maturity and temperature.

Marais, E., Jacobs, G. and Holcroft, D. M.

Scientia Horticulturae. Volume 90, Number 1-2, 2001. Pages 31-41.

2001

บทคัดย่อ

Preliminary experiments indicated that postharvest irradiation enhanced anthocyanin synthesis in Cripps' Pink apples. Consequently, this system was used to understand the effects of maturity and temperature on anthocyanin synthesis. Fruits harvested 5, 4, 3, 2 and 1 weeks prior to predicted commercial harvest did not develop a red blush in response to postharvest irradiation (72 h with high-pressure sodium lights at 20 deg C). Fruits harvested at maturity rapidly developed a red blush in response to irradiation. Mature Cripps' Pink apples harvested from two growing regions were subjected to 120 h of irradiation at 6 or 20 deg C following 0, 2 or 5 days at -0.5 deg C. Fruits harvested from the cooler area (Ceres) and irradiated immediately showed greater red colouration at 6 deg C than at 20 deg C. The difference between the temperatures was no longer significant after fruits have been stored for 5 days at -0.5 deg C prior to irradiation. Fruits harvested from the warmer area (Grabouw) were consistently redder when irradiated at 6 deg C than at 20 deg C. In a separate experiment, fruits were stored for 20 days at -0.5 deg C prior to irradiation at either 6 or 20/6 deg C (day/night). The alternating temperature resulted in better colour of fruits from both areas. In a final experiment, well-coloured Cripps' Pink apples were irradiated at 37 deg C to simulate periods of high temperature that occur in summer. The hue angle of the fruits increased from 29.3-48.3 deg after 144 h of light, indicating a loss of red colour. The anthocyanin concentration decreased >50% during the same period. Fruits kept at 37 deg C in the dark did not lose red colour.