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The process of microwave osmotic dehydration of mango was optimized under continuous flow medium spray conditions (MWODS) with maltodextrin (10DE) moderated sucrose solutions. Optimization was carried out using a response surface methodology with a central composite rotatable (CCRD) design with three input variables at five levels (temperature, 33 C to 66.7 C; sucrose:maltodextrin ratio from 100:0 to 80:20; and solute concentration, 33 to 66.7%). The response parameters used for optimization were moisture loss (ML), solids gain (SG), weight reduction (WR), ML/SG ratio, color and texture values. For each response, RSM models (p < .05) were developed. As expected, all output variables were responsive to process variables and addition of maltodextrin to sucrose was found to have a significant effect on reducing the SG and increasing ML/SG, and total solute concentration had significant effects on ML, SG and quality parameters. The process was optimized by desirability approach and MWODS at 56 C with total osmotic solute 46% concentration and 84:16 sucrose:maltodextrin proportion had the highest desirability value.Selection of constraints was an influential factor as well. Practical ApplicationsOsmotic dehydration (OD) has many advantages, but is a slow process. Carrying out OD in MW environment accelerates the process, enhances moisture loss (ML) and limits the solids gain (SG). The quality of OD foods is related to ML/SG ratio and the MWOD process enhances ML/SG. This can be further enhanced by incorporating high molecular solutes like maltodextrins. This research optimizes the maltodextrin moderated MWOD process under continuous medium flow conditions. The process offers significant potential for reducing the treatment time (to 30 min) and improve the ML/SG ratio. The resulting product can be finish dried, used as intermediate moisture food or frozen (dehydrofreezing).

The microwave osmotic dehydration of mango cubes under the continuous flow of maltodextrin moderated sucrose solution spray (MWODS) was evaluated based on the quality of the finish air-dried product. Experiments were designed according to a central composite rotatable design to evaluate the effect of maltodextrin moderated sucrose solution [sucrose + maltodextrin (10DE) at a proportion of 85:15] on the finish air-dried product. The process variables were temperature (30 to 70 °C), solute concentration (30 to 70%), contact time (10 to 50 min) and flow rate (0.8 to 3.8 L/min). The optimum processing conditions were determined based on several processes and product-related quality parameters such as moisture loss (ML), solids gain (SG), weight gain, ML/SG, color, texture, rehydration capacity (RHC), bulk density and drying time. The MWODS contact time was the largest significant contributor with respect to most of the parameters, followed by temperature. The optimum values found were an osmotic treatment temperature of 51.7 °C, a solute concentration of 58.5%, a contact time of 30.6 min and a solution flow rate of 1.8 L/min. Finally, these optimized processing conditions were used to compare three different solute mixtures [sucrose only, sucrose + dextrose and sucrose + maltodextrin (10DE) at a ratio of 85:15%] to understand the effect of various solutes on the quality of the finished dried product. Based on the color and textural parameters, along with the RHC, of the finished product, the sucrose + maltodextrin mixture was shown to result in the most desirable quality and the air-dried product without MWODS pretreatment (control) resulted in the least desirable. Overall, the results suggest that the sucrose + maltodextrin combination offered an advantage in terms of quality for the MWODS air-drying of mango cubes.

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