EFFECTS OF COMBINING POSTHARVEST CALCIUM AND HEAT TREATMENT ON REDUCING DECAY AND MAINTAINING QUALITY IN APPLES

Abstract

Heat treatment of `Golden Delicious' apples (Malus domestica Borkh) at 38C for 4 days, pressure infiltration with 2 or 4% solutions of CaCl2, or a combination of both with heat following CaCl2 treatment affected both decay and firmness during 6 months storage at 0C. The heat treatment alone reduced decay caused by B. cinerea by about 30%, while heat in combination with a 2% CaCl2 solution reduced decay by about 60%. CaCl2 solutions of 2 or 4% alone reduced decay by 40% and 60%, respectively. Heat treatments, either alone or in combination with CaCl2 treatments, best maintained firmness (80 N), followed by fruit infiltrated with 2 or 4% solutions of CaCl2 alone (70 N) and then the nontreated controls (66 N). Instron Magness-Taylor and Instron Compression Test curves show that heat treated fruit differed qualitatively and quantitatively from nonheated fruit. A combination of heat treatment after CaCl2 infiltration increased surface injury over those fruit heated or infiltrated with CaCl2 solutions alone.