CHILLING TEMPERATURE STORAGE INDUCES CHANGES IN PROTEIN-PATTERNS AND PROTEASE ACTIVITY IN CHERIMOYA FRUIT

Storage at 6 degrees C inhibited the ripening process and caused sever e damage in cherimoya fruit (Annona cherimola Mill. cv. ''Fino de Jete '). In the present study, we analyzed the modifications in protein pat tern, free amino acid content and protease activity of cherimoyas duri ng storage at this chilling temperature. SDS-PAGE analysis revealed no n-accumulation of some polypeptides related to the ripening process du e to storage at 6 degrees C, and two-dimensional electrophoresis confi rmed the appearance of specific low-temperature polypeptides. While ma ny polypeptides observed in freshly harvested fruit persisted during s torage, several acid polypeptides were detected only during the first few days of storage at 6 degrees C. A substrate-dependent change in pr otease activity was also found in fruit under chilling temperature sto rage, as compared to ripening fruit. After a decrease to barely detect able levels during the early phase of cold storage, the proteolytic ac tivity then increased, mainly hydrolizing endogenous proteins to free amino acid components.