Sensory and firmness measurements of calcium- and heat-treated apples

'Golden Delicious' apples were held at 38C for 0 or 4 days and treated with 0 or 0.14 mol . L-1 CaCl2 . 2 H2O, stored at 0C for six months, and then h eld at 20C for 7 days. Texture and quality were measured by nondestructive sonic vibration, Magness-Taylor (MT) puncture and axial compression of tiss ue specimens using a force/deformation testing instrument, and sensory eval uation by untrained panelists. Prestorage treatment with heat, calcium, or the combination significantly improved the poststorage firmness over that o f untreated control fruit. MT firmness values and crispness scores were hig her for heat-treated apples than far controls, but the Ca and combination t reatments resulted in significantly higher values. Calcium infiltration sig nificantly increased sensory hardness and overall acceptability scores, as well as the location of the maximum force in compression, regardless of hea t treatment. Apples exposed to heat before storage were sweeter than those not heated. Only the controls were scored in the unacceptable range for cri spness and overall acceptability. Crispness mean scores could be predicted by the destructive puncture and compression tests (r(2) = 0.93) and to a mo derate level by the nondestructive sonic vibration test (r(2) = 0.72). None of the instrument measurements adequately predicted acceptability scares. Although calcium infiltration resulted in the best poststorage quality, pre storage heat treatments may provide a practical, economical means of improv ing poststorage quality of apples.