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

'Golden Delicious' apples (Malus domestica Borkh.) were treated with heat or CaCl2 Solutions or a combination thereof to determine the effects of these treatments on decay and quality of fruit in storage. Heat treatment 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 decay and firmness during 6 months of storage at 0C. The heat treatment alone reduced decay caused by Botrytis cinerea (Pers.:Fr.) by almost-equal-to 30%, while heat in combination with a 2% CaCl2 Solution reduced decay by almost-equal-to 60%. Calcium chloride solutions of 2% or 4 % alone reduced decay by 40% and 60%, respectively. Heat treatments, either alone or in combination with CaCl2 treatments, maintained firmness (80 N) best, followed by fruit infiltrated with 2% or 4% solutions of CaCl2 alone (70 N) and 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. Heat treatment did not increase the amount of infiltrated Ca bound to the cell wall significantly, and a combination of heat treatment after CaCl2 infiltration increased surface injury over those fruit heated or infiltrated with CaCl2 solutions alone.