FIRMNESS AND DECAY OF APPLES FOLLOWING POSTHARVEST PRESSURE INFILTRATION OF CALCIUM AND HEAT-TREATMENT

Heating 'Golden Delicious' apples (Malus domestica Borkh.) for 4 days at 38C or pressure-infiltrating them with a 4% CaCl2 solution reduced decay and maintained fruit firmness during 6 months of storage at 0C. Heating reduced decay caused by Penicillium expansum Link ex Thom by a lmost-equal-to 30%, while pressure inriltration with CaCl2 reduced dec ay by >60%. Pressure inriltration with CaCl2 after heating reduced dec ay by almost-equal-to 40%. Pressure infiltration maintained firmness b est (>84 N), as measured with a manually driven electronic fruit-firmn ess probe, followed by heat and CaCl2 (76 N), heat alone (71 N), and n o treatment (control) (60 N). Force vs. deformation (FD) curves from a puncture test with a fruit-firmness probe mounted in a universal test ing machine showed that fruit heated before storage were firmer than a ll nonheated fruit, except those pressure-infiltrated with 4% CaCl2. H owever, FD curves also showed that apples pressure-infiltrated with 4% CaCl2 differed quantitatively from apples in all other treatments, in cluding those heated.