Sweet Whey

Sweet Whey: Nutritional Reference

Sweet whey is the liquid byproduct produced when milk is coagulated by rennet — the enzyme complex that causes milk proteins (caseins) to form a gel — and the resulting curds are cut, cooked, and pressed to expel liquid. It is generated in the production of rennet-coagulated cheeses including cheddar, Gouda, Emmental, mozzarella, and most hard and semi-hard varieties. Sweet whey has a higher pH than acid whey (around 6.2 versus 4.5 for acid whey) and a different mineral composition — more calcium remains in the rennet curd rather than dissolving into the whey liquid. Sweet whey is far more commercially valuable than acid whey because it can be spray-dried relatively easily into whey powder, which is used extensively in food manufacturing, infant formula, and sports nutrition supplements. The whey protein isolates and concentrates that form the basis of the global sports nutrition industry are derived from sweet whey — the proteins remaining in sweet whey (primarily beta-lactoglobulin and alpha-lactalbumin) are highly bioavailable, complete proteins with an excellent amino acid profile for muscle protein synthesis.

Nutritional Composition of Sweet Whey

Liquid sweet whey provides 27 kcal and 0.85 g of protein per 100 ml, with 0.36 g of fat — a low-calorie liquid. In its dried form as whey powder, the nutrient concentrations are dramatically higher: approximately 330 kcal, 11 g protein, and 1 g fat per 100 g. Whey protein concentrate (WPC80) provides approximately 400 kcal and 80 g of protein per 100 g. Sweet whey contains lactose, B vitamins (particularly riboflavin), phosphorus, calcium, and magnesium.

Uses of Sweet Whey

In home cheesemaking, sweet whey from rennet cheeses can be used to make ricotta — heating the whey to near boiling with a little acid causes the remaining whey proteins to denature and float to the surface, which can then be scooped off and drained as a soft, light ricotta-like product. Use sweet whey in bread baking (replacing water), in smoothies, in cooking grains, or as a base for soups and sauces. In Scandinavian dairy tradition, sweet whey is reduced to make the brown caramelised whey cheeses such as gjetost/brunost. The lactose caramelises during the long reduction, producing the characteristic sweet, fudge-like flavour of these traditional Nordic products.