In dairy industry butter and cheese are main products while buttermilk is by-product.
Buttermilk is fermented milk with characteristically sour taste. The tartness of buttermilk is due to the presence of acid in the milk.
Today it becomes common to produce cultured buttermilks from skim or whole milk. The culture most frequently used is Streptococcus lactis, perhaps also spp. cremoris.
The most significant by-product from dairy processing industry is whey, generated from the cheese-making process. Liquid whey is the part of milk that separates from the curd during cheeses production. Approximately 80% of the milk that is used to make cheese is converted to whey, or about 1 gal of whey per pound of cheese.
Once considered a waste product is now widely accepted to contain many valuable constituent.
A number of opportunities exist for the recovery or utilization of the lactose and protein content of whey. It can be fed to animals as is or dried and can also use for animal and human diets.
The components of whey include beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, lactoferrin, immunoglobulin, lactoperoxidase enzymes, glycomacropeptides, peptones, lactose and minerals.
Other dairy by products include:
*Casein is the solid residue obtained from rennet coagulation of defatted milk. By definition, it contains at least 80% protein.
*Dried skim milk is sometime used in starter diets due primarily to its excellent digestibly and amino acid balance. It protein content is about 34%.
Dairy by-products
