Protein-lactose matrix effects on fat encapsulation during the overall spray-drying process of dairy powders

摘要

Fat encapsulation by a protein-lactose matrix has been investigated all along the spray-drying process of fat-filled dairy powders. The matrix was made of micellar casein, whey proteins or heat-denatured whey proteins, alone or with amorphous lactose. Results showed that the presence of amorphous lactose was essential to emulsify and encapsulate fat: it could act as a hydrophilic protective agent, especially with heat-denatured whey proteins. With amorphous lactose, micellar casein and whey proteins were better emulsifiers than heat-denatured whey proteins with regard to the formation of fat droplet with smaller size; however, only native whey proteins proved to be better encapsulating agents with regard to free fat and surface fat. Hence, whey proteins, when weakly heat-denatured, and in the presence of amorphous lactose, could be used as effective ingredients to encapsulate fat in dairy powders.