Fruit degreening

Pigment synthesis inhibition Flower initiation Flower inhibition Flower sex shifts Fruit growth stimulation Fruit degreening Fruit ripening Respiratory changes Storage product hydrolysis Latex secretion promotion... 

Schemske DW, Bradshaw HD (1999) Pollinator preference and the evolution of floral traits in monkeyflowers (Mimulus). Proc Natl Acad Sci USA 96 11910-11915 Wang HC, Huang XM, Hu GB, Yang Z, Huang HB (2005) A comparative study of chlorophyll loss and its related mechanism during fruit maturation in the pericarp of fast- and slow-degreening litchi pericarp. Sci Hortic 106 247-257...

Degreening of peel has been related to chlorophyllase activity. Barmore (14) demonstrated that chlorophyllase activity in peel increased following treatment of fruit with ethylene. 

Cohen (21) has suggested the use of an "intermittent" exposure to ethylene and heat for degreening. The method consists of treating fruit with 10 ppm of ethylene at 25°C for 12 hr intervals. During the 12 hr interruption, the ethylene dropped to 0 to 1 ppm and the temperature dropped 1 to 2°C. 

Using this procedure, there was a decrease in respiration rate with less loss in fruit weight. There was less decay and the color development was similar to fruit treated by continuous degreening. 

Exposure of citrus fruits to ethylene has been shown to increase the incidence of stem-end rot caused primarily by D natalensis (113, 124, 125, 126, 127). Higher than recommended ethylene concentrations (75, 106, 116, 128, 129) and temperature (116) and an increase in degreening duration (116, 125) caused significant increases in stem-end rot. Anthracnose, caused by . gloeosporioides, is a serious disease of specialty citrus hybrids such as Robinson, Lee, Nova, and Page (130, 131), when fruit are exposed to ethylene. Incidence was related directly to length of degreening (130), ethylene concentration (132,... 

This procedure requires 2 to 3 weeks during which time juice yield and citric acid increase (153). In an effort to speed up the process, ethephon or standard degreening practices have been used but these usually enhance decay, particularly stem-end rot (126, 148, 150, 153). Degreening was achieved with standard degreemng practices if mature fruit were treated with an effec-... 

During ripening of non-climacteric fruits like citrus, the process of colour change is named degreening and the natural loss of chlorophylls, accumulated into the chromoplasts of the epidermis (flavedo) and vesicles, and the concomitant manifestation and new biosynthesis of carotenoids, generally occurs very slowly (Eaks 1977). 

Fig. 10.7 Changes in L parameter and colour indices (Chroma, CCl, AE, a /b, and Hue) on the flavour of Newhall orange during degreening at 22 °C and 95% RH on untreated (control) and continuous 5 ppm C2H4 treated fruit, and after subsequent six days at 20 C and 70-75% RH (retail sale and distribution simulated period).

Table 10.3 Changes in some ehemieal parameters during degreening of Rio Red grapefruit at 22 °C, 95% RH on untreated (eontrol) and eontinuous 5 ppm C2H4 treated fruit, and subsequent shelf life of six days at 20 °C and 65-70% RH... 

JIMENEZ M, CUQUERELLA J and MARTINEZ JM. 1981. Determination of a color index for citrus fruit degreening. Proa Int. Soa Citriculture 2 750-753. 

MAJOR USES Used in the production of pharmaceuticals, paint and plastics solvent propellant refrigerant degreening agent in citrus fruit. 

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