Influence of Top Spray Fluidized Bed Agglomeration Conditions on the Reconstitution Property and Structure Modification of Skim Yoghurt Powder

Abstract

Spray dried yoghurt powder (Control) has small particle size (57 µm) that cause high cohesiveness forces between particles. Wetting time of control yoghurt powder takes more than 1 hr by forming lump on the surface of water. Smaller particle size cause higher contact surface area per unit mass of powder that limits flowability of yoghurt powder. Yoghurt powder turned into instant form due to particle size enlargement by applying agglomeration process. In addition, agglomerates showed lower bulk, tapped, and particle densities and excellent flowability. Effects of inlet air temperature (50–80 °C), atomizing pressure (0.5–1.5 bars) and sprayed water amounts (50–80 g) were investigated in this study. Response surface methodology was used to find the best conditions in view of high quality reconstitution properties of yoghurt powder. The best process conditions were determined as 62.5 °C inlet temperature, 0.9 bar atomizing pressure and 68 g sprayed water amount. Practical applications: Optimization of top sprayed fluid bed agglomeration process parameters has not yet been studied for dairy powders. By using optimization process, effects of agglomeration process parameters (inlet air temperature, amount of binder, and atomization pressure) on quality parameters of yoghurt powder were revealed. Improvement of yoghurt powder reconstitution properties will be the first study in the literature. These studies provide an insight for further studies about top spraying bed agglomeration process. © 2017 Wiley Periodicals, Inc.