An original way to produce functional particles by dry heating whey proteins
Résumé
Whey proteins present in milk are widely used in the food industry for their nutritional and functional properties. Many studies have been undertaken on the improvement of functional properties of these proteins, mainly by heat-induced denaturation/aggregation in the liquid state. Depending on the heating conditions, a large variety of aggregates having different structures and different physicochemical properties, and remarkable techno-functional properties, such as gelling, foaming or emulsification are produced [1]. While many works have been dedicated to whey proteins heat-treated in a solution, less studies considered heat as applied in a solid or a dry state.
Whey protein solutions at pH 9.5 are freeze-dried or spray-dried. Then, whey protein powders are conditioned at a water activity of 0.24 and dry heated at 100°C. The color of powders and the presence of particles were followed during the dry heating time.
Uncommon large stable particles are formed by this dry heat treatment. The lactose content is a critical factor for the kinetics of particle formation, via glycation and the Maillard reaction. The kinetics of particle formation is studied as a function of the lactose content in powders. Functional properties of particles are also studied such as their water entrapment and flow properties. Dry heat-induced particles retain a huge amount of water, and are able to bring large viscosity values.
These particles could be used in food formulation to replace undesirable food additives.