Comparison of cell wall degrading enzyme activities during ripening of guava fruit on-tree and in-storage

Changes in the activities of various cell wall degrading enzymes, viz., exo-polygalacturonase (PG), β-Dgalactosidase, cellulase and pectin methyl esterase (PME) were assayed on alternate days. Activities of PG, β-D-galactosidase and cellulase increased continuously with the advancement of ripening on-tree as well as in-storage, whereas the activity of PME showed a fluctuating trend, it initially increased and thereafter showed a declining trend during ripening on-tree as well as in-storage. Further the activities of PG, β-D-galactosidase and cellulase showed a very high negative correlation with loss of fruit firmness during ripening, whereas the activity of PME did not showed a significant correlation with firmness. Changes in the activities of all the enzymes studied were faster during ripening in-storage as compared to ripening on-tree in both the cultivars; however cv. Hisar Surkha exhibited faster changes than cv. Hisar Safeda. Changes in enzymatic activities were rapid in rainy season than winter season crop.