Biochemical changes associated with hardening of endocarp in Spondias mangifera Willd. fruits during developmental stages

Spondias mangifera is a unique, fleshy, drupe fruit with a mango flavor. The hardening of endocarp during development and maturation of hog plum is a major bottleneck, which reduces the edibility of the fruits by 80% and makes them unmarketable. For the first time, three distinct maturity stages were demonstrated. Distinct pattern in change in surface color, accumulation of carotene pigments and biochemical components in fruits were observed. The decrease in chlorophyll ‘a’ and chlorophyll ‘b’ correlated well with the downhill trend in Transmittance Refractory Spectroscopy (TRS) – ‘L’, ‘a’, ‘b’ values. The decrease in the total chlorophyll along with the accumulation of carotene pigment contributes significantly to the lightness of surface color and reflected in ‘L’ hue values. Confluence of carotene and total chlorophyll on the 9th week provides a distinct marker for maturity. Complete convergence of five carpells on the 9th week after fruit set, heralds the onset of maturation in Indian hog plum and which was adjudged as visual index of maturity. Hardening of endocarp begins after attainment of optimum maturity and last for 2 weeks. Pre-climacteric plunge in respiration along with coordinated changes in pigments, and accumulation of ascorbic acid, phenols, presets the optimum maturity period of 9th week after fruit set. Pre-climacteric falls in respiration with lowest output of 40.57 mg CO₂/kg-h concentration on 9th week after fruit set indicates the attainment of fruit maturity. Harvesting of hog plum between 9th and 11th weeks provides the fruit with soft endocarp and complete edibility.