Changes in pectic enzymes and cellulase activity during guava fruit ripening

Changes in activities of the cell wall degrading enzymes, pectinesterase (PE), polygalacturonase (PG) and cellulase, were studied during the ripening of white- and pink-fleshed guava fruit types. PE activity increased in both guava types up to the climacteric peak of respiration (flesh firmness of 1.21 kg/cm2) and subsequently decreased. Activities of PG and cellulase increased progressively during the ripening of both guava fruit types with a high correlation between the increase in the activity of the two enzymes and the loss of fruit flesh firmness.