Seasonal Variation and Developmental Changes in the Biochemical Composition of Coconut Kernel in Mohachao narel, A Sweet Endosperm Coconut (Cocos nucifera L.) Population from Maharashtra

Abstract

Mohachao Narel’, a coconut variant characterized by sweet and soft kernel with less fibre content, has been reported from Guhaghar taluk of Ratnagiri district of Maharashtra State in India. Farmers of the area get a premium price for sweet endosperm nuts and the sweet kernel is mainly used for raw consumption. A total of 27 mother palms possessing nuts with sweet kernel have been identified in these areas. The number of nuts with sweet endosperm per bunch varies from 10 to 77 percent in these 27 palms. Thus two types of nuts (sweet and normal) have been developed in these palms. The solid endosperm, kernel, undergoes biochemical changes as it matures during its 12- month growth period after fertilization. The objective of this work was to study these biochemical changes in the coconut endosperm in relation to the maturity of the nuts and season of harvesting between and within the sweet and normal type nuts. The dried kernel or copra was analyzed for its oil, total sugars, reducing sugars, total protein, total free amino acid and fibre contents. Both the sweet and the normal nuts harvested in the post monsoon season had higher oil, total sugar and fibre contents, but lesser kernel protein and amino acid contents than the nuts harvested during pre-monsoon and monsoon seasons. Sweet nuts had higher levels of total sugar and reducing sugar contents, but less fibre and oil contents than the normal nuts. Total protein and amino acid contents were found to be similar in both types of nuts. Percentage of oil content of kernel, in both types of nuts, was increasing steadily from seventh to twelfth month of maturity. Both types of nuts were found to have a significant increase in soluble sugar with nut maturity, to a maximum in the tenth month, after which it fell significantly in the twelfth month. In both type of nuts, harvested at different seasons, reducing sugar was maximum in the seventh month, after which it decreased to a minimum by the tenth month, it again increased by the twelfth month. In both the types of nuts, there was a significant decrease in protein and free amino acid contents as the nut matured. But both type of nuts showed the same trend of increasing in fibre content as the endosperm matured.