To make milk protein concentrate, whole milk is first separated into cream and skim milk. The skim milk is then fractionated using ultrafiltration to make a skim concentrate that is lactose-reduced. This process separates milk components according to their molecular size. Milk then passes through a membrane that allows some of the lactose, minerals, and water to cross through. The casein and whey proteins, however, will not pass through the membrane due to their larger molecular size. The proteins, lactose, and minerals that do not go through the membrane are then spray dried. Spray drying and evaporation further concentrate the remaining materials to form a powder. Depending on the purpose of the final product, different heat treatments can be used to process ultrafiltered or blended varieties of MPC. An MPC product processed with low heat will maintain higher nutritional value.
Functionality in food
Applications of MPC include: use in nutritional beverages, nutritional and dietary products, aged care products, infant formulas, protein bars, yogurts, recombined cheeses, cultured products, frozen desserts, bakery and confection applications. MPC can be financially advantageous to producers of milk for cheese production, as its addition increases the protein level of the product achieving greater cheese yield for less capital investment.
“MPC contains micellar casein, whey proteins, and bioactive proteins in the same ratio found in milk. As the protein content of MPC increases, the lactose levels decrease. This high-protein low-lactose ratio makes MPC an excellent ingredient for protein-fortified beverages and foods and low-carbohydrate foods.”
MPC can make products more heat stable, and it can provide solubility and dispersibility when used. This solubility makes MPCs beneficial in dairy-based mixes. MPC is useful in foaming and whipping: “The proteins in MPC act at air/water interface to form a stable film of air bubbles. This stabilizes meringues, mousses, cakes, ice creams, whipped cream and soufflés.” “The proteins in MPC act at the oil/water interface to form and stabilize fat emulsions in sausages and other processed meats, dairy drinks, soups, vinaigrettes, sauces and bakery products.” Essential in many of its applications, an MPC can increase the viscosity of a food product due to its interior protein structure. “The lactose and proteins in MPC undergo Maillard browning, resulting in an appealing color for bakery products such as pastries, cakes and muffins.” Because MPC has virtually no taste, it allows the other flavors of a food to fully develop.