Changes in Properties during Maturation and Ripening of ‘Chiin Hwang No. 1’ Mango Fruit Cultivated in a Plastic Greenhouse

Abstract

Mango fruits ‘Chiin Hwang No. 1’ produced on 7-year-old trees cultivated in a plastic greenhouse {inside temp.: in winter, min. 5.8°C (room) and 12.7°C (soil); in summer, max. 42.5°C (room) and 26.8°C (soil)} were used for this study. Fruits were harvested approximately 13 (Sample I), 15 (Sample II) and 17 (Sample III) weeks after flowering in 1999. Sample III was ripened at 25°C, 58–84% RH for 12 days. Brix value, respiratory rate, and free sugar content increased during maturation. These values increased markedly when the fruits of Sample III were ripened. The surface color remained practically unchanged during maturation, but with ripening Hunter b and a values began to increase at a late stage. The b value of flesh color, particularly in the apex portion, increased gradually, and with ripening the L value decreased, while the a and b values increased. The flesh firmness remained almost constant during maturation, but decreased markedly during ripening. Citric acid, an abundant organic acid, decreased gradually as maturity progressed. Though fructose content was nearly constant throughout maturation and ripening, sucrose content increased rapidly with storage at 25°C. AIS (alcohol insoluble solid), starch and total pectin reached maximum levels in Sample II and decreased in Sample III. Furthermore, the contents of these substances decreased significantly with ripening, and the decrease in starch was marked. Changes in the activities of amylase, polygalacturonase, and pectin esterase during maturation and ripening suggested correlations with the changes in content of starch and pectins. The results in the changes of Brix value, flesh firmness, and chemical composition suggest that the optimal time for harvesting ‘Chiin Hwang No. 1’ mango fruit is 17 weeks after flowering.