Whey powder

Whey powder (WP) is simply dried liquid whey. The manufacture of WP firstly involves a clarification and centrifugation step to remove any cheese fines and residual fat prior to further processing.

Whey powders are used as food ingredients in many applications, from chocolate and sugar confectionery, bakery, soups and sauces, baby foods, etc., with different types used in different foodstuffs. The standard whey powder product is anhydrous whey powder made from sweet whey, the by-product of cheesemaking where acidification is not excessive and pH is 6.3–6.5 (e.g. emmental and gruyere production). Sweet whey is evaporated to 60–70% solids to supersaturate lactose and flash cooled to 30 °C, at which point a-lactose crystals form. Further cooling to 15 °C causes the mutarotation of β-lactose to a-lactose and some 75–80% of the lactose crystallises. The whey concentrate can then be spray-dried. Some of the lactose (up to 20%) remains in the amorphous state, which is hygroscopic. Whey powder is packaged in, for example, polyethylene-lined Kraft paper sacks with high water-barrier properties to prevent moisture ingress and the development of a sticky powder.

Undemineralised whey powder can be used in a variety of food applications, although in some such as infant foods (and calf milk replacers).