Drying of milk–blackberry pulp mixture in spouted bed

Abstract

Spouted bed drying of a paste mixture of milk and blackberry pulp using inert beads of polystyrene and polypropylene was analysed in this work. Atomisation and dripping of the paste were compared as feeding modes. The experimental design used atomisation feeding to analyse the effects of air temperature, paste feeding flow rate and paste atomisation pressure on the drying performance. The best results were obtained for drip feeding on polystyrene beads, yielding powder production efficiency >60%, low final moisture content of the powder and <15% anthocyanin degradation.