Effects of Ethylene Degreening, Low-temperature Quarantine Treatment, and Storage Temperature on Coloration of ‘Ponkan’ Mandarin (Citrus reticulata Blanco cv. ‘Ponkan’).

• Main Authors: Yu-Tzu Huang, 黃祐慈
• Other Authors: Fu-Wen Liu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/80695595575569193046

碩士 === 國立臺灣大學 === 園藝學研究所 === 92 === Early-harvest‘Ponkan’mandarins (Citrus reticulata Blanco cv. ‘Ponkan’) are usually greenish in color. In order to find practical means to enhance yellow coloration of the fruit, the effects of ethylene degreening, simulated low-temperature quarantine treatment, and storage temperature management on coloration were studied. The peel color was visually estimated and expressed as percent yellow coloration followed by instrumental measurement with a color difference meter. The measurements included L*, a*, and b*, and were later converted into a*/b* value, hue angle, and L* value. Green Ponkan had very little color change during a fifteen-day simulated low-temperature quarantine treatment. After the quarantine treatment, Ponkan turned yellow faster at 15℃ than at 10℃ or 20℃. Coloration was slowest at 25℃. Ponkan without low-temperature quarantine treatment also turned yellow faster at 15℃, followed by 10℃, 20℃, and 25℃ in that order. Mature green Ponkan harvested 14 days earlier and stored at 15℃ for 14 days were yellower than similar fruit harvested 14 days later. Degreening treatment with 5 ppm ethylene for 48 hours at 25℃ either before or after low-temperature quarantine treatment accelerated coloration of Ponkan. Ethylene-degreened Ponkan turned completely yellow 5 to 15 days earlier than similar fruit not degreened. Ethylene degreening caused stem and calyx browing in some fruit. Ethylene treatment after low-temperature quarantine treatment caused fewer stem and calyx brownings than ethylene treatment before quarantine treatment, however. Ethylene effectively degreened Ponkan without low-temperature quarantine treatment as well. Ethylene degreened Ponkan either with or without low-temperature quarantine treatment colored equally well at 10℃, 15℃, or 20℃. Both a*/b* and hue angle could indicate the Ponkan peel color more precisely than visually estimated percent coloration. L* value increased concurrently with visually observed coloration percentage in coloring Ponkan until reaching a peak, which coincided with 100% coloration, and then slightly declined corresponding to deepening of yellow color.