Co-Authors:
Shalom, N.B., Department of Food Science, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Hanzon, J., Department of Food Science, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Pinto, R., Department of Food Science, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Lurie, S., Department of Postharvest Science, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Abstract:
Prestorage heat treatment (38°C for 4 days) retarded the softening of 'Anna' apple fruits during 0°C storage. Fruit softening of unheated apples during storage was accompanied by changes in pectic substances: a decrease in uronic acid content in the carbonate-soluble fraction and an increase in the water-soluble fraction. Heat treatment partially inhibited the degradation of uronic acids in the cell wall. The degree of pectin methylation in both heated and non-heated fruit decreased during storage. In heat treated apple fruit the content of galactose and arabinose in the cell wall decreased during storage; in non-heated fruit only galactose decreased. We suggest that the inhibition of solubilisation of the carbonate soluble pectin fraction is one of the main factors contributing to the firmness retention caused by heat treatment. The loss of both arabinose and galactose in heat treated fruits may also play an as yet undefined role in the effect of heat treatment on fruit softening.