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 coagulation1 of the casein proteins in cheesemaking. Whey contains most of the lactose2 and about 20% of the protein3 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:
- Discharged4 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-off5 ends up in waterways increases the growth of aquatic plants and the biological oxygen demand of the water. This impacts on fish and other aquatic6 organisms. Whey can also restrict nutrient7 availability in the soil, although rotating paddocks for irrigation can help reduce this issue.
Cheesemaking generates large volumes of whey. About 80% of the volume8 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 evidence9 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 consumer10 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 acids11 – 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 muscle12 mass in older adults
- weight loss – whey proteins can increase satiety13 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 heat14 setting | Maintains moistness and improves texture and mouth feel. | Baked products, beverages, dairy products, yoghurts |
| Solubility | Easily dispersed in most systems. Prevents sedimentation15 in beverages, soups and sauces. | Beverages, confectionery, frozen desserts, infant formula, soups and sauces |
| Water binding and building viscosity16 | 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 ethanol17, 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.
- coagulation: When a substance groups small particles together to form larger particles or clots.
- lactose: A type of sugar found in milk and milk products.
- protein: Any of a large class of complex compounds that are essential for life. Proteins play a central role in biological processes and form the basis of living tissues. They have distinct and varied three-dimensional structures. Enzymes, antibodies and haemoglobin are examples of proteins.
- discharge: 1. The conversion of chemical energy to electric energy. 2. A flowing out or pouring out.
- run-off: Water carried away from land to streams and rivers.
- aquatic: Growing or living in or near water (either freshwater or marine).
- nutrient: A substance that provides nourishment for growth or metabolism.
- volume: 1. The quantity of space occupied by a liquid, solid or gas. Common units used to display volume include cubic metres, litres, millilitres, tablespoons and teaspoons. (Volume can refer to a large quanity of something). 2. The degree of sound intensity or audibility; loudness.
- evidence: Data, or information, used to prove or disprove something.
- consumer: 1. An organism that feeds on other organisms to obtain energy for life processes. These organisms are also called heterotrophs. 2. A person who purchases goods and services for personal use.
- amino acid: The basic building block of proteins. A short chain of amino acids is called a peptide, and a long chain of amino acids (normally more than 50) is called a protein.
- muscle: The tissue that makes it possible for an animal to move and to maintain its posture. Muscles also make the heart beat, force blood to circulate and move food along the digestive system. The human body has more than 600 muscles.
- satiety: The lack of appetite or hunger for a period of time following a meal.
- heat energy (heat): Heat energy: the transfer of energy in materials from the random movement of the particles in that material. The greater the random movement of particles the more heat energy the material has. Temperature is a measure of the heat energy of a material.
Heat: the flow of energy from a warm object to a cooler object. - sedimentation: The process of depositing sediment. Sedimentation rates can change by altering land use, e.g. deforestation tends to increase sedimentation, and exposed sediments can be carried along by wind and surface water and into rivers for eventual deposition in the sea.
- viscosity: The measure of resistance of a fluid to flow. Thick slow-flowing liquids have a high viscosity, thin fast-flowing liquids have a low viscosity.
- ethanol: A volatile, flammable, colourless liquid. It is also known as ethyl alcohol or pure alcohol.
