The potential of computational fluid dynamics simulation to investigate the relation between quality parameters and outlet temperature during spray drying of camel milk

Abstract

The lack of appropriate quality indicators for Computational fluid dynamics (CFD) prediction of spray drying of camel milk impeded the simulation of the process. This research is designed to correlate the temperature profile of powder particles with the solubility of camel milk proteins with the ultimate goal of identifying best quality indicators suitable for CFD simulation. Spray drying experiment was conducted by varying drying temperature from 140–200 °C while maintaining the drying air flow rate (7.5 m3/min), emulsion feed rate (0.0003 kg/s) and atomization pressure (0.52 MPa) constant. The moisture content of camel milk powder varied from 7.04% [w/w] at lower temperature (140 °C) to 2.7% [w/w] at higher temperature (200 °C). Yield of powder could be increased with inlet temperature only up to 160 °C. Similarly, moisture removal from camel milk could be increased with temperature only up to 160 °C. From this point onward, powder yield and moisture removal showed inverse relation with temperature. CFD predicted the outlet temperature with 0.43% and 0.73% errors at inlet temperature of 140 °C and 170 °C, respectively and with 8.69% error at 200 °C. The loss of solubility of αS1- and κ-caseins as determined by SDS-PAGE of spray dried camel milk powders correlated well with the CFD predicted temperature profiles of particles. The SEM images of the powders illustrated that more round type particles are produced at higher temperature for both cow and camel milks whereas shriveled type powders at lower temperature only for cow milk.