Analysis of Foaming Properties of Mango Pulp for Foam-mat Drying: Impact of Egg Albumin Concentration and Whipping Time

Recently, the preservation of fruits and vegetables by foam-mat drying becomes popular as its simple and low cost, minimum drying time and thermal degradation, the efficiency of viscous foods and retaining the food quality. The foaming properties, including foam expansion, stability, density, porosity and viscosity, play a significant role in improving the heat and moisture transfer rate and product quality. In this study, the influence of egg albumin concentration and whipping time on the foaming properties of mango pulp was investigated. The egg albumin concentrations of 5, 10, 15 and 20% were added with mango pulp and then whipped using an electric hand blender at a maximum speed of 1200 rpm. The foaming properties were tested at 5, 10 and 15 min whipping time intervals. The results showed that the foam volume, foam stability and foam porosity increased significantly, whereas decreased foam density with increased concentrations of egg albumin. As required for foam-mat drying, the result showed a maximum foam expansion (104.6%), highest foam stability (91.87%), minimum foam density (0.447 g/cm 3 ), optimal foam porosity (0.5113) and viscosity (2368.72 mPa s) at 15% egg albumin concentration at a whipping time of 10 min. The foam obtained in the ideal foaming condition was stable up to 210 min. The photomicrograph of the foams showed a high number of bubbles at 15% egg albumin at a whipping time of 10 min.