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 Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins ( αS1, aS2, β, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in hum ...

plus

lactalbumin Lactalbumin, also known as " whey protein", 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 are contained in milk. Targeted small scientific s ...

) 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

Processing

To make milk protein concentrate,

whole milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulating ...

is first separated into

cream Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this process ...

and skim milk. The skim milk is then

fractionated Fractionation is a separation process in which a certain quantity of a mixture (of gases, solids, liquids, enzymes, or isotopes, or a suspension) is divided during a phase transition, into a number of smaller quantities (fractions) in whi ...

using

ultrafiltration Ultrafiltration (UF) is a variety of membrane filtration in which forces such as pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the ...

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 is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix ' ...

, minerals, and water to cross through. The casein and

whey protein Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Glycomacropeptide also ma ...

s, 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 is a method of changing 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, or materials which may requ ...

and

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when h ...

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 formula Infant formula, baby formula, or simply formula (American English); or baby milk, infant milk or first milk (British English), is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, usually prepar ...

s, protein bars,

yogurt Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in the milk by these bac ...

s, recombined

cheese Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During productio ...

s, 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

levels decrease. This high-protein low-lactose ratio makes MPC an appealing ingredient for protein-fortified beverages and foods and low-carbohydrate foods. MPC can make products more heat stable, and it can provide

solubility In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubi ...

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

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Alth ...

s 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 The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the int ...

of a food product due to its interior protein structure. The lactose and proteins in MPC undergo

Maillard browning The Maillard reaction ( ; ) is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. Seared steaks, fried dumplings, cookies and other kinds of biscuits, breads, toasted marshmallows, and many ...

, 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 2002, the FDA issued a Warning Letter to

Kraft Foods The second incarnation of Kraft Foods is an American food manufacturing and processing conglomerate, split from Kraft Foods Inc. in 2012 and headquartered in Chicago, Illinois. It became part of Kraft Heinz in 2015. A merger with Heinz, arran ...

that Kraft Singles and

Velveeta Velveeta is a brand name for a processed cheese product similar to American cheese. It was invented in 1918 by Emil Frey of the "Monroe Cheese Company" in Monroe, New York. In 1923, "The Velveeta Cheese Company" was incorporated as a separate c ...

were being sold with packaging that described it as a "Pasteurized Process Cheese" and "Pasteurized Process Cheese Spread" respectively, which the FDA claimed were misbranded because the products declared milk protein concentrate (MPC) in its ingredients listing. Both products are now sold in the US as a "Pasteurized Prepared Cheese Product","What Is 'Real Kraft Cheese'?"
''Chicago Business'', 5 February 2007. Accessed 3 February 2008. a term for which the FDA does not maintain a standard of identity, and which therefore may contain MPC. In the US dairy farmers are protected from international competitors with a range of measures, including

tariffs A tariff is a tax imposed by the government of a country or by a supranational union on imports or exports of goods. Besides being a source of revenue for the government, import duties can also be a form of regulation of foreign trade and po ...

on imports. MPCs however are not subject to a tariff rate quota, so most MPCs used are imported. US dairy producer groups claim that foreign manufacturers using nonfat dry milk in the production of MPC are circumventing existing quotas on nonfat dry milk."Schumer Urges Clampdown"
Senator Charles E. Schumer's website

References

* {{DEFAULTSORT:Milk Protein Concentrate United States Department of Agriculture Milk