Effect of osmotic dehydration process on the physical, chemical and sensory properties of osmo-dried cantaloupe

The objective of this research was to study the effect of osmotic dehydration process (fast osmotic dehydration; FOD and slow osmotic dehydration; SOD) on the physical, chemical and sensory properties of osmo-dried cantaloupe. First, the effect of calcium salts (calcium chloride and calcium lactate) on the firmness of fresh cantaloupe was investigated to obtain the suitable immersion time, types of calcium salt and their concentrations for the pretreatment step prior to osmotic dehydration process. It was found that the proper condition for pretreatment step was 2% calcium lactate for 3 h as considered from the firmness and sensory evaluation. After pretreatment, cantaloupe slices were subjected to two osmotic dehydration processes and then dried in hot air oven to obtain osmo-dried cantaloupe. The physical, chemical and sensory properties of osmo-dried cantaloupe obtained from FOD and SOD were comparatively determined. The result showed that no difference in colour (L*, a*, b* values) and browning index was found between sample produced by FOD and SOD. SOD could maintain the shape and present softer texture, resulting in higher mean score of appearance as evaluated by consumers. However, lower vitamin C, phenolic compound and DPPH radical scavenging activity were found in sample produced by SOD compared to FOD. The sensory evaluation was found to be better in sample produced by SOD as considered from appearance and texture scores. However, no difference in mean score of overall acceptability was observed between sample produced by FOD and SOD process.