Nutritional quality of muskmelon fruit as revealed by its biochemical properties during different rates of ripening

Muskmelon (Cucumis melo L.) is one of the economically important fruit in the world and the important quality determining parameters of it are carbohydrates and antioxidants. In the present study antioxidants such as phenols, polyphenols, ascorbic acid, carotenoids, total antioxidant activity as well as sweetness related compounds like reducing, non-reducing and total sugars, starch and activities of various enzymes related to these biochemical components were evaluated in muskmelon at its sequential stages of development and ripening. Even though the amounts of sugars and phenolics increased with the progress of ripening, other antioxidants like ascorbic acid, carotenoids and level of total antioxidant activity however, decreased. The activities of antioxidant enzymes such as peroxidase and polyphenol oxidase gradually increased towards ripening with their maximum of it in the ripened and pre-ripened stage respectively, whereas catalase displayed its maximum activity in the premature stage. Sugar metabolizing enzyme, sucrose phosphate synthase exhibited positive correlation with the sucrose accumulation concomitant with the decreased activities of sucrose synthase, acid invertase and neutral invertase towards ripening of the muskmelon fruit. Ultimately the carbohydrates and bioactive compounds with their accumulation in the ripe muskmelon fruit suggests its use to the food scientists to maximize the nutritional value, thereby confirming muskmelon fruit as a nutritionally balanced source of dietary antioxidants.