Mandarin Juice Powder Production by Foam Mat Drying: Optimization and Determination of Drying Kinetics

Foam mat drying is a promising development with the advantages of low cost and can be used as an alternative to drum and spray drying for drying aqueous foods. The economic value and importance of mandarin fruits are increasing day by day due to their rich nutritional content, ease of marketing, easy peeling compared to other citrus fruits, the existence of varieties that ripen at different times, and their resistance to cold. The aim of this study was to optimize the production conditions of mandarin juice foam with response surface methodology, to examine the drying kinetics of hot air and freeze-drying methods, and to express the drying behavior of mandarin juice foams with mathematical modeling. Egg albumen was used as a foaming agent at different concentrations (0, 1.5, and 3% w/w), and carboxymethyl cellulose (0, 1, and 2% w/w) was used as a foam stabilizer. Optimum production conditions were found as a whipping time of 6 min 20 s, an egg albumen concentration of 3% (w/w), and a carboxymethyl cellulose concentration of 2% (w/w). Under the optimized conditions, density, stability, and expansion values of foam were found as 0.262 (g/cm³), 348.955, and 302.516%, respectively. The drying times for temperatures of 50, 60, 70, and -52 °C were determined as 105, 82, 70, and 180 min, respectively. Based on mathematical modeling, the "Page" model was found to be suitable for all temperature values.