Thesis (BS Food Technology) -- University of the Philippines Mindanao, 2003

To correlate texture characteristics of abnormal robbery and normal soft ripe bananas (Musa AAA Group, Cavendish subgroup) with the cell wall polysaccharide composition, partial characterization of polysaccharide fractions of the isolated cell wall material (CWM) from each type of banana was elucidated in this study. The average yields of crude CWM from normal soft and abnormal rubbery pulp were 7.6% and 10%, respectively. Water-soluble (WS), starch hydrolysates, EDTA-soluble, alkaline-soluble monosaccharide compositions. Rubberiness was directly associated with high total sugar content in the WS (1.96%), alkaline-soluble (0.62%) and residue (2.16%) fractions suggesting presence of greater amounts of pectin, hemicellulosic and cellulosic molecules in the cell walls of abnormal rubbery bananas. These findings corresponds more to the generally higher total uronic acid content solubilized by EDTA in the normal soft cell walls (1.79%) than in the corresponding abnormal rubbery cell walls (1.57%) particularly in the EDTA-fraction. These results indicate that ripening and subsequent softening of bananas is accompanied by degradation of the cell wall polysaccharides. Gas chromatographic analysis of the monosaccharide composition of the isolated polysaccharides showed higher individual sugar quantities mostly in the cellulosic fraction (residue) of the abnormal rubbery cell walls. This indicates that abnormal rubbery bananas have relatively thicker cell walls than the normal soft bananas. Thus, rubberiness in bananas can be explained by difference in the cell wall integrity as a function of their structural organization and polysaccharide compositions