Heating can reduce the respiration rate and the turgor loss during the storage of cut fruit. In addition, the heating treatment can reduce the total microbial count during the first storage day and prevent the growth of lactic acid bacteria that occur in untreated fruit after 8 days of storage. The sensory evaluation indicated that heating treatment increased sweet aromatic flavours and reduced undesirable flavours, such as bitter, musty, fermented, and sour.
Also, the role of calcium in stabilizing cellular membranes and delaying senescence in horticultural crops is well known technique. Pre- and postharvest application of calcium can delay senescence in commercial and retail storage of fruit with no detrimental effect on consumer acceptance. Post-cut calcium treatment of produce improves firmness retention and product shelf-life.
The objective of Lamikanra and Watson (2007) was to evaluate the biochemical effects of hot water treatment on fresh-cut cantaloupe melon during storage. The effect of processing cantaloupe melon, immediately after heat-treatment compared to holding the fruit at 4 °C for 24 h before processing, was assessed. The same aim was pursued for dissolved calcium in the treatment water.
For the research, Cantaloupe melon (Cucumis melo L. var. reticulates), supplied by Del Monte Fresh Produce Co. (Coral Gables, FL), was received at 4 °C. Heat-treatment consisted of immersing fruit in the water-bath, set at 60 °C, for 60 minutes. For calcium treatment, calcium lactate (1%) solution was used. After removing seeds and skin, the melon was cut into cubes, approximately 2-3 cm x 2.5 cm. About 300g of cubes from each tested melon were placed into 1 litre-container and stored at 10 °C. The effect of treatments on the fruit storage was assessed by determination of respiration rate (O2 e CO2 gas analysis in the container headspace), by assay of enzymatic activity (peroxidase and lipase) responsible of tissue browning and softening, and by texture analysis on fruit.
Results indicated that hot water pre-treatment of cantaloupe melon before processing could be used to prolong shelf-life of the cut fruit. Heat treatment reduced respiration rate of cut fruit during storage. Results indicated that it was more beneficial to store treated fruit for 24 h at 4 °C than to process the fruit immediately after heat treatment. Calcium treatment did not affect respiration rate, CO2 accumulation was higher in the calcium-treated samples than in untreated fruits.
Enzymatic activity resulted lower during storage of fruit processed 24 h after heat-treatment, on the contrary calcium addition in the solution inhibited the potentially beneficial effect of heat-treatment by increasing lipase activity in the fruit. Hot-water pre-treatment increased the firmness and cohesiveness of cut melon, however may reduce the springiness during storage of fruit held at 4 °C for 24 h after heating before processing. Calcium treatment did not influence the textural changes due to the heat-treatment.
Original research: Lamikanra O. and Watson M.A., "Mild heat and calcium treatment effects on fresh-cut cantaloupe melon during storage", 2007, Food Chemistry, Issue No. 102, Pag. 1383-1388.