During ripening, ‘Hass’ avocado fruit develops exocarp colour from emerald-green to purple, then black, which is regulated by anthocyanin; specifically, by cyanidin 3-O-glucoside. Branch girdling and maturity has been shown to increase carbohydrate accumulation and fruit colour in several fruit crops. This study determines the interactive effect between girdling and harvest maturity to improve avocado fruit exocarp colour development during ripening. In this study, early (25 and 29% dry matter content) and mid-maturity (28 and 32% dry matter content) fruit harvested from girdled and control trees were cold stored at 5.5 °C for 28 days, respectively. Fruit were evaluated for firmness, visual colour and chromaticity (lightness-L*, chroma-C*, hue-angle-ho), exocarp total anthocyanin and carotenoids, chlorophyll-a and -b and cyanidin 3-O-glucoside were also quantified during ripening. Exocarp colour development was poor in ripened fruit harvested from girdled trees during early and mid-harvest. Thus, girdling and harvest maturity did not enhance total anthocyanin or cyanidin 3-O-glucoside enzymatic synthesis; therefore, exocarp colour changed during ripening. In conclusion, girdling of ‘Hass’ avocado trees did not promote carbohydrate accumulation in the fruit exocarp, resulting in low cyanidin 3-O-glucoside accumulation during ripening.
Keywords: Anthocyanin, carbohydrates accumulation, chlorophyll-a and -b, cyanidin 3-O-glucoside