Influence of foam thickness on production of lime juice powder during foam-mat drying: Experimental and numerical investigation

The present study aimed at investigating the effect of foam thickness (0.004, 0.005, 0.006 m) on lime juice foam mat drying at 50 degrees C and with ovalbumin (4% concentration) as the foaming agent. The process was also simulated in order to examine the effect of foam thickness on temperature and moisture distributions. The model was validated by comparing experimental data with model data. The increase in foam thickness led to a 3.11% decrease in water solubility index (WSI) and a 14.47% increase in water absorption index (WAI). By increasing foam thickness from 0.004 to 0.006 m, the drying rate decreased by 3333%. Furthermore, the effective moisture diffusion coefficient (D-eff) values ranged between 8.980 x 10(-9) and 1.138 x 10(-8) m(2)/s. The increase in foam thickness decreased total color change, chroma index, and browning index by 4.45, 3.88, and 2.19%, respectively. There was a good correspondence between experimental and simulation data. The correlation coefficient obtained by comparing experimental with predicted data was >0.91. The uniform distribution of temperature and moisture during the foam-mat drying process enhanced the qualitative properties of the final product, which in turn resulted in higher quality lime juice powder. (C) 2017 Elsevier B.V. All rights reserved.