Kinetic modeling of microwave osmotic dehydration of mangoes under continuous flow medium spray conditions using sucrose and maltodextrin (10-18 DE) solute mixtures

Abstract

Microwave osmotic dehydration of mango (Mangifera indica) was carried out under continuous spray mode (MWODS) with four osmotic solute mixtures (sucrose (S), sucrose in combination with maltodextrin (MD) 10 dextrose equivalent (DE), 15DE, and 18DE), at two temperatures (40 °C, 60 °C) and two concentrations (40%, 60%) and four contact times (10, 20, 30, 40 min). The mass transfer kinetics were fitted to a first-order kinetic model, by way of an empirical parameter (k) representing an overall mass transfer coefficient. Azuara model was also evaluated to describe the mass transfer kinetics. The results showed that the overall mass transfer coefficients for moisture and solids contents were influenced by temperature, concentration and, more importantly, the solute composition. The highest mass transfer coefficient for moisture loss (1.56 E⁻²) and lowest for solids gain (8.60 E⁻³) observed with sucrose + maltodextrin 10DE (S + MD 10DE) combination at 60%/60 °C and 40%/40 °C, conditions, respectively. In addition, the Azuara model well fitted the experimental data for mass transfer kinetics (R² > 0.92). The highest moisture loss (ML) along with lower solids gain (SG) was associated with the solute sucrose + maltodextrin 10DE combination. The highest ML/SG ratio of 10 and weight reduction of 55.5% were observed with S + MD 10DE at 40 °C/60%/40 min and 60 °C/60%/40 min, respectively, with S + MD 10DE solute mixture. Overall, it was possible to successfully describe the mass transfer kinetics using empirical first order and Azuara models and MWODS with S + MD 10DE facilitated the maximum moisture loss and low solids uptake, both desirable from osmotic dehydration point of view.

Keywords:

• Drying
• osmosis
• moisture loss
• solids gain
• modeling

Acknowledgments

This paper was prepared in part based on the keynote presentation by the senior author at the ADC2019 conference, Vadodara, India, December 14–17, 2019.