Spray freeze drying of dairy products: Effect of formulation on dispersibility

Milk powders are commonly produced by using the technique of spray drying. In this work, we propose the use of spray freeze drying technology to improve the re-dispersibility of milk powders in aqueous systems. We explore how formulation can influence the re-dispersibility of dairy products. Due to higher porosity and lower tapped density, milk powder produced by spray freeze drying showed an average 15% percentage higher re-dispersibility than spray-dried powders after only 20 s of agitation. Higher fat percentages and the presence of an additive, maltodextrin, worsened the re-dispersibility of spray freeze-dried dairy powders. An increase in 6% of fat percentage decreased the percentage of redissolved powder by 30%. Similarly, an increase in 5% maltodextrin weight resulted in a 5% lower re-dispersibility. The results of this study shall be fundamental in providing future guidelines for the use of spray freeze drying technique for producing milk and other dairy powders with high quality and nutrient retention.