A multivariable approach for intensification of foam-mat drying process: Empirical and three-dimensional numerical analyses

Foam-mat drying has been recently welcomed as an effective technique since it lacks deficiencies that plague conventional methods such as long processing time. It is essential to apply appropriate and inexpensive drying methods for producing powders from heat-sensitive foods such as lime juice. Therefore, this study aimed to intensify the interaction effects of multi variables including ovalbumin concentration, foam thickness and air temperature to analyze their simultaneous interactions on quality characteristics during lime juice drying. The process was also modeled to study the effect of ovalbumin concentration, foam thickness and air temperature on moisture and temperature distributions. Results showed that an increase in ovalbumin concentration reduced the foam density while increasing its expansion, porosity and stability. Higher air temperature, ovalbumin concentration and foam thickness reduced water solubility index and increased water absorption index. Increasing temperature from 50 to 70 degrees C intensified the drying rate by 25.58%. Moreover, chroma index, hue angle and browning index decreased by increasing temperature. Model performance was evaluated by comparing experimental and model data (R-2 = 0.911). In summary, the lime juice powders produced by foam-mat drying process yielded promising results in terms of product's color, water absorption, porosity and flowability, among other quality characteristics.