1992 Volume 39 Issue 11 Pages 960-965
Papaya was wrapped with a polyethylene film and artificially damaged by vapor heat treatment before use. As a result, the vole of polygalacturonase (E.C. 3.2.1.15) (PG), softening enzyme, in the damage of papaya during vapor-heating was observed. Three electrophoretically different PG isozymes, namely PG-1, PG-2 and PG-3 were found. PG-2 and PG-3 were notably involved in the softening of papaya. The molecular weights of polyuronide changed by decomposition or dissolving by enzymes such as PG, etc. In consequence, the molecular weight of polyuronide decreased from 990000 to 100000 in both the normal fruits and the non-defective parts of damaged fruits. It proved a normal progress of ripening was occured in proportion to growth of fruits. However, no decrease of molecular weights was observed in the defective part of the damaged fruits. This fact led to an assumption that non-ripening of fruits may attribute to incomplete degradation of polymeric galacturonic acids.
