Milk protein concentrate
Encyclopedia
Milk protein concentrate (MPC) is any type of concentrated milk product that contains 40–90% milk protein. The United States officially defines MPC as “any complete milk protein (casein
plus lactalbumin
) concentrate that is 40 percent or more protein by weight.” In addition to ultrafiltered milk
products, the MPC classification includes concentrates made through other processes, such as blending nonfat dry milk with highly concentrated proteins, such as casein
.
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.
“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, vinaigerettes, 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.
in the production of MPC are circumventing existing quotas on nonfat dry milk. Further concern arises as MPCs are largely unregulated.
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....
plus lactalbumin
Lactalbumin
Lactalbumin is the albumin contained in milk and obtained from whey. Lactalbumin is found in the milk of many mammals. There are alpha and beta lactalbumins; both contained in milk....
) concentrate that is 40 percent or more protein by weight.” In addition to ultrafiltered milk
Ultrafiltered milk
Ultrafiltered milk is a subclassification of milk protein concentrate that is produced by passing milk under pressure through a thin, porous membrane to separate the components of milk according to their size, permitting greater efficiency in cheese making...
products, the MPC classification includes concentrates made through other processes, such as blending nonfat dry milk with highly concentrated proteins, such as casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....
.
Processing
To make milk protein concentrate, whole milk is first separated into creamCream
Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, over time, the lighter fat rises to the top. In the industrial production of cream this process is accelerated by using centrifuges called "separators"...
and skim milk. The skim milk is then fractionated using ultrafiltration
Ultrafiltration
Ultrafiltration is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane...
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
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
, 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
Spray drying
Spray drying is a method of producing a dry powder from a liquid or slurry by rapidly drying with a hot gas. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals. A consistent particle size distribution is a reason for spray drying some...
and evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
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 cheese milk, 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
Lactose
Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
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
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
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, vinaigerettes, sauces and bakery products.” Essential in many of its applications, an MPC can increase the viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher 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.
Impact on the United States
In the US dairy farmers are protected from international competitors with a range of measures, including tariffs on imports. MPCs however are not subject to a tariff rate quota, so most MPCs used are imported. “The United States imports of MPCs’ have doubled in the last five years, and between 2007 and 2008 MPC imports increased 66 percent.” The majority of these imports come from New Zealand, totaling $250 million worth of MPC imported worldwide. US dairy producer groups claim that foreign manufacturers using nonfat dry milkPowdered milk
Powdered milk is a manufactured dairy product made by evaporating milk to dryness. One purpose of drying milk is to preserve it; milk powder has a far longer shelf life than liquid milk and does not need to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for...
in the production of MPC are circumventing existing quotas on nonfat dry milk. Further concern arises as MPCs are largely unregulated.