Biochemical studies related to textural regulation during ripening of banana and mango fruit.
Bhagyalakshmi N., Prabha T. N., Yashodha H. M., Prasanna V., Jagadeesh B. K., Tharanathan R. N.
Author Affiliation: Central Food Technological Research Institute, Mysore 570 013, India.
: 717-724
Abstract : The changes occurring during ripening of Cavendish banana (Musa sapientum [M. paradisiaca]) cv. Robusta and Alphonso mango were studied, with emphasis on carbohydrates and the carbohydrate hydrolases responsible for textural softening. In both banana and mango there was a significant increase in soluble sugars, mainly in the reducing types. There was a gross increase in uronides and a steady decrease in starch, cellulose, hemicellulose and pectins during each stage of ripening. The new observation made in the present study is that xylanase [xylan endo-1,3-?-xylosidase] and laminarinase [endo-1,3(4)-?-glucanase] among the glycanases, and ?-mannosidase followed by ?-galactosidase among glycosidases, appeared to play a crucial role in textural softening of banana. Similarly, in mango, glycanases such as mannanase [?-mannosidase], galactanase [arabinogalactan endo-1,4-?-galactosidase] and arabananase were recognized as the key enzymes for textural degradation. There was a major drop in molecular weights of carbohydrate polymers during ripening of mango with the complete disappearance of low molecular weight polysaccharides of below 70?000 daltons. This information is useful for monitoring, at the biochemical level, the textural loss during ripening of banana and mango without inhibiting ethylene-associated natural ripening.