Post-harvest biochemical changes associated with the softening phenomenon in Capsicum annuum fruits

Changes in the activities of various cell-wall hydrolases were followed during ripening of bell pepper (Capsicum annum). The activity of polygalacturonase (PG) increased. while that of pectin methyl esterase (PME) decreased. The texture of the fruit declined concomitantly with the increase in PG activity. The behaviour of the glycanases, namely cellulase, xylanase, mannanase, glucanase and galactanase, and glycosidases, like alpha-D-mannosidase and beta-D-galactosidase, were monitored. The influence of low storage temperature (8 degrees) on the enzyme activities was studied in which PG, PME, cellulase, mannosidase and galactosidase were suppressed to different levels. Sugar composition of the alcohol-insoluble carbohydrate residue was also analyzed during ripening. Galactose (10%) was the major sugar followed by arabinose (4.2%). The amount of the neutral sugar which was Initially 25% decreased to 15% during ripening, resulting in a nearly 40% loss; the changes mainly involved reduction in galactosyl and arabinosyl residues.