Foam mat drying of tomato pulp

Abstract

The purpose of this study was to optimize the formulation of tomato pulp foam and to evaluate the drying process using the foam mat method at temperatures of 60°C and 80°C. The optimization was conducted by analyzing the effect of the albumin concentration (expressed in %) and whipping time (expressed in minutes) in relation to the response variables of foam density and thermal stability of the foam based on the volume of remaining foam. The drying curves (moisture versus drying time ratio) for the control treatment (CT; no albumin addition) and optimized treatment (OT) were obtained. The results showed that only the whipping time variable (linear and quadratic effects) had significant influence (p < 0.05) on the foam density values. The foam stability was significantly influenced by the whipping time (p < 0.10) and albumin concentration (p < 0.10). The optimum foam formation conditions considering higher foam stability and lower density included a 4.5% albumin concentration and a 4.5 minutes of whipping time. The results of the drying curves showed that the foam formation with albumin significantly reduced (p < 0.05) the time necessary to reach moisture equilibrium during drying. The moisture equilibrium values were not significantly different (p > 0.05) among the treatments with foam application at the studied temperatures, but they were lower than the treatments without foam application.