Milk protein concentrate (MPC) is any type of concentrated milk product that contains 40–90%milk protein, typically from cow milk. The United States officially defines MPC as "any complete milk protein (casein pluslactalbumin) concentrate that is 40 percent or more protein by weight."[citation needed] In addition toultrafiltered milk products, the MPC classification includes concentrates made through other processes, such as blending nonfat dry milk with highly concentrated proteins, such ascasein.
To make milk protein concentrate,whole milk is first separated intocream andskim milk. The skim milk is thenfractionated usingultrafiltration to make a skim concentrate that is lactose-reduced.[1] This process separates milk components according to their molecular size. Milk then passes through a membrane that allows some of thelactose, minerals, and water to cross through. Thecasein andwhey 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.[2]Spray drying andevaporation further concentrate the remaining materials to form a powder.[1] 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.[2]
Applications of MPC include: use in nutritional beverages, nutritional and dietary products, aged care products,infant formulas,protein bars,yogurts, recombinedcheeses, 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.[2]
MPC contains micellar casein, whey proteins, and bioactive proteins in the same ratio found in milk. As the protein content of MPC increases, thelactose levels decrease. This high-protein low-lactose ratio makes MPC an appealing ingredient for protein-fortified beverages and foods and low-carbohydrate foods.[2]
MPC can make products more heat stable, and it can providesolubility and dispersibility when used.[2] This solubility makes MPCs beneficial in dairy-based mixes.[3] 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.[3] The proteins in MPC act at the oil/water interface to form and stabilize fatemulsions in sausages and other processed meats, dairy drinks, soups, vinaigerettes, sauces and bakery products.[3] Essential in many of its applications, an MPC can increase theviscosity of a food product due to its interior protein structure.[3] The lactose and proteins in MPC undergoMaillard browning, resulting in an appealing color for bakery products such as pastries, cakes and muffins.[3] Because MPC has virtually no taste, it allows the other flavors of a food to fully develop.[3]
In 2002, theFDA issued aWarning Letter toKraft Foods thatKraft Singles andVelveeta were being sold with packaging that described it as a "Pasteurized Process Cheese" and "Pasteurized Process Cheese Spread" respectively,[4] 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",[5] 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, includingtariffs 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 usingnonfat dry milk in the production of MPC are circumventing existing quotas on nonfat dry milk.[6][7]
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This article incorporatespublic domain material fromJasper Womach.Report for Congress: Agriculture: A Glossary of Terms, Programs, and Laws, 2005 Edition(PDF).Congressional Research Service.