Whey has gone from being a waste product from cheesemaking to a highly valued coproduct. Whey is now widely used in the food industry for its nutritional and functional benefits.
What is whey?
Whey is the watery liquid that remains after the coagulation of the casein proteins in cheesemaking. Whey contains most of the lactose and about 20% of the protein in milk.
Find out more about the science of cheese.
Traditional disposal of whey
Traditionally, cheesemakers considered whey a waste product and looked for the most economical way to dispose of it. Generally, they discarded it in one of three ways:
- Discharged into waterways.
- Sprayed onto farmland.
- Sold for a low return as animal feed.
Environmental issues bring restrictions on whey disposal
Disposing of whey into waterways or spraying it onto pasture where run-off ends up in waterways increases the growth of aquatic plants and the biological oxygen demand of the water. This impacts on fish and other aquatic organisms. Whey can also restrict nutrient availability in the soil, although rotating paddocks for irrigation can help reduce this issue.
Cheesemaking generates large volumes of whey. About 80% of the volume of milk used to make cheese remains as whey. As the dairy industry has grown worldwide, the volumes of whey have increased substantially. Growing concerns about the impact on the environment prompted governments to impose restrictions on its disposal.
Advances in science and technology
Environmental concerns and regulations led to deeper research into whey components and opportunities for using them in useful and higher value products. This has provided a greater understanding of the properties and benefits of whey. The scientific evidence has helped in promoting and developing wider uses of whey.
Alongside this, there have been advances in technologies for processing whey more efficiently, as well as increasing consumer interest in products using whey-based ingredients such as functional foods and nutraceuticals.
Nutritional value of whey
Whey is highly valued for its nutritional benefits, particularly whey protein. This is a rich source of essential amino acids – the building blocks of muscles and other human tissues. Whey proteins are also easily digested and quickly absorbed by the body. These properties make them valuable ingredients in products for health and wellbeing. Nutritional uses and benefits include:
- sports nutrition – enhancing athletic performance and improving recovery from exercise
- infant nutrition – supplementing infant formulas helps match the protein concentration in human milk
- healthy ageing – whey proteins can help build and maintain muscle mass in older adults
- weight loss – whey proteins can increase satiety and help maintain lean body mass.
Functional properties of whey
Whey products are also known for their functional properties. This makes them a valuable ingredient in formulating food products with benefits including improving flavour and texture and increasing yield.
Function | Benefits | Uses |
| Emulsification | Creates stable emulsions and prevents fat globules from forming clumps. | Baked products, beverages, ice-cream mixes, mayonnaise-type dressings |
| Flavour enhancement | Brings out already present flavours or adds flavour. | Baked products, beverages, confectionery, snacks |
| Gelling and heat setting | Maintains moistness and improves texture and mouth feel. | Baked products, beverages, dairy products, yoghurts |
| Solubility | Easily dispersed in most systems. Prevents sedimentation in beverages, soups and sauces. | Beverages, confectionery, frozen desserts, infant formula, soups and sauces |
| Water binding and building viscosity | Provides fat-like attributes in products allowing reduction in fat content, improved texture and moistness. | Baked products, beverages, dairy products, coffee creamers, soups and sauces |
| Whipping, foaming and aeration | Maintains foam properties, enhancing appearance, taste and texture. | Baked products such as meringues and cakes, confectionery, ice-cream, frozen desserts |
Manufacturing ethanol from whey
Whey can also be processed into ethanol, which is used in pharmaceuticals, perfumes, inks and alcoholic beverages.
Activity idea
In Separating curds and whey students investigate how variations in processing cheese curd impact on the final cheese characteristics. There is also an extension activity for students to learn how these cheese characteristics relate to the molecular structure of the cheese.
