Implication of cell wall degrading enzymes in the heat‐induced softening of the African pear (dacryodes edulis (G Don) H J Lam)

Abstract Extracts of the pulp of mature fruits of African pear (Ducryodes edulis) were assayed for the activities of the cell wall degrading enzymes cellulase, pectin esterase, polygalacturonase and proteinase. All enzymes were found to be endogenous to the pear pulp. Studies on the softening temperatures of the fruit revealed that softening of pear pulp slices was negligible at room temperature (28°C) and 100°C but most effective in the range 60‐85°C. Moreover, there was a close correlation between this effective softening temperature range and the optimum temperatures of the cell wall degrading enzymes. These results suggest that the heat‐dependent softening of the African pear pulp may be due to induction of endogenous cell wall degrading enzymes by heat.