WHAT IS ACID CASEIN?
Acid casein is a casein product that is created when an acid is added to pasteurized skim milk causing coagulation and precipitation of the casein protein. Acid casein exists as a free-flowing powder. The general composition of acid casein is around 86.5% protein, 0.5% lactose, 2% ash, 1% fat, and 10% moisture, all of which vary slightly by manufacturer.
HOW IS ACID CASEIN MADE?
Skim milk that has been pasteurized is heated and coagulated by an acid leading to precipitation of the casein protein. The acid is added to the milk until the pH reaches the isoelectric point of casein, 4.6. The most common acids that are used to make acid casein are hydrochloric acid and sulfuric acid that have been diluted to the strength required to cause coagulation. Once the milk has coagulated, the whey is drained off and the curds are washed thoroughly with water. The casein curds are pressed, ground down thoroughly, and dried with heat which evaporates out the remainder of the water left in the curds to form a powder that is milled to the appropriate mesh size.
WHAT IS ACID CASEIN USED FOR?
Acid casein is most used in protein bars and processed cheese or cheese analogues as an additive. Acid casein is also used in other non-food related items like paint, paper, and plastics. Some functional properties of acid casein include its ability to improve textures in food products, its emulsification properties, and its ability to support water retention. The softening aspect of acid casein helps to keep doughs and cheeses more malleable and extend the shelf life of the overall product.
WHAT DOES ACID CASEIN TASTE LIKE?
Acid casein overall has a very neutral flavor profile in its most perfect form. Acid casein more commonly has a tortilla and animal note with a sour taste. Towards the end of the acid caseins’ shelf-life, the product starts to have stronger cardboard and paper notes. The mouthfeel is somewhat gritty as acid casein is generally not soluble in water unless further treatments are added to modify the product. Acid casein can have more aroma and some brothy or barny off flavors than other milk powders.
WHAT ARE THE FUNCTIONAL PROPERTIES OF ACID CASEIN?
Acid casein is an excellent ingredient to add to food and beverages to lower viscosity and increase malleability in the finished good. Acid casein is also an emulsifier and this property also helps to give softer texture to bars and baked goods. Acid casein supports water retention and can help keep bars and baked goods soft and less brittle. Acid casein is used as an additive to improve nutritional benefits of a food by increasing the protein content. In industrial applications, acid casein can help create films to improve the functionality of the paper and plastic goods.