Carbohydrate metabolism in ripening Banana Fruit

Prabha, T. N. and Bhagyalakshmi, N. (1998) Carbohydrate metabolism in ripening Banana Fruit. Phytochemistry , 48 (6). pp. 915-920.

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Abstract

A comprehensive picture of changes in carbohydrates, carbohydrate hydrolases, cell structure and texture in banana fruit during ripening is described. The insoluble carbohydrates were separated into seven fractions based on differential solubility. Their profiles and composition were followed as hydrolysis products. The starch and pectic fractions decreased considerably in ripe banana pulp. The significant decrease in glucose concentration in the hydrolysates of cold and hot water-soluble polysaccharides and that of xylose in the hydrolysates of hemicellulosic fractions (Hem A annd B), indicated a pronounced glucan and xylan degradation during ripening. Some loss of mannose from the Hem “B” fraction at the ripe stage was also noticed. The various carbohydrate hydrolases, viz., polygalacturonase, pectin methyl esterase, xylanase, laminarinase, α-mannosidase, β-galactosidase, amylase, cellulase and hemicellulase registered a general increase in their activities. Low levels of endo-β-mannanase and galactanase activities could be detected only at the climacteric stage of ripening. More than 80% of the radio-activity of [14C] starch was incorporated into soluble sugars, viz., glucose, fructose and sucrose, indicating active sugar interconversions. The total content of these soluble sugars increased from 1.8 to 19%, with a concomitant decrease in starch content during ripening. Microscopically, loss of cell wall integrity, cell wall thinning, increased intercellular spaces, loosening of cells and disappearance of starch granules were evident. In banana, it appears that pectinase may play a more dominant role in softening than cellulase. Amylase, xylanase and laminarinase may also contribute to loosening of cellular structures.

Item Type:	Article
Uncontrolled Keywords:	Musa sapientum; Musaceae; banana; softening; carbohydrates; carbohydrate hydrolases; 14C incoporation
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 13 Carbohydrate Chemistry 600 Technology > 08 Food technology > 24 Fruits > 02 Banana
Divisions:	Plant Cell Biotechnology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	24 Sep 2007 10:56
Last Modified:	28 Dec 2011 09:30
URI:	http://ir.cftri.res.in/id/eprint/1424

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