Home > Focus stories > Mining milk > What to do with whey waste?
Secondary students investigate the properties of whey (a waste product from cheese-making) and find ways that bioprocessing can reduce the impact and/or amount of whey waste.
To show the potential of whey waste. To demonstrate that a technological solution is the result of research and development of a range of options with the selection being justified in terms of its environmental effects and acceptability to the community as well as its functionality.
Suggestions for a scenario
A casein extraction factory is faced with the problem of what to do with the whey that is produced as a by-product. Carry out tests to find out the properties and functionalities of whey and propose a bioprocess that would utilise this whey.
Where's the Biotechnology?
Casein (‘curds’) is a protein extracted from milk and is used to make cheese, as well a range of other products. The liquid left over after the casein is removed is called whey.
Whey, a by-product, is sometimes dumped, or else sprayed on arable land. This causes problems with runoff as it increases the growth of aquatic plants and the biological oxygen demand (BOD) of waterways. This is because whey contains a wide range of compounds (proteins, lactose, calcium, phosphorus, vitamins, and many other nutrients). Instead, whey can be processed to produce a wide range of commercial products. For example, the whey can be developed into high protein products (e.g. whey butter, whey cheese, protein powders for food manufacture) and whey-based food additives with particular properties (e.g. gels that bind fat to water in canned products, meats, pates and sausages as well as in desserts). The lactose can be separated and used in alcoholic fermentation (using micro-organisms) to produce gin and fortified wines, or converted (via enzyme reactions) to make glucose/galactose syrups for sweeteners.
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Home > Focus stories > Mining milk > What to do with whey waste?
Technology
Technological Knowledge: Bioprocessing utilises scientific and engineering principles that are applied to biological processes, for example the extraction and processing of whey waste to produce products and reduce pollution.
Technological Practice: Environmental issues and acceptability of products are a critical aspect when defining specifications for an appropriate technological outcome. For example, consumers of organic products, consumers who are lactose-intolerant and consumers requiring high value products for medical diets.
Science
Properties of substances. Chemical processes and their safe and appropriate application.
Focus of skill & strategy
This unit demonstrates the potential for integrating science and technology programmes. Students will have the opportunity to develop an understanding of chemical processes and how they can be applied in a biotechnological situation.
Health and Safety
Because the extraction of whey is carried out in a non-sterile environment, no taste-testing or consumption of products should occur.
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Home > Focus stories > Mining milk > What to do with whey waste?
UNIT PLAN: WHAT TO DO WITH WHEY WASTE?
Suggested learning intentions
Suggested learning experiences
Whey production is a significant component in the production of casein.
The following learning experiences will provide you with starting points for an exploration of this topic. You may decide to narrow your focus to one component, or include most of the ideas in a unit that incorporates science and/or technology themes.
Introducing the problem
Is whey a problem when making casein?
Introduce different methods of making casein (curds) and whey:
 make junket (identify the curds and whey)
 make butter (measure the buttermilk/whey).
The amount of whey produced varies with the method of casein extraction.
And / or
Students can extract whey from casein using different processes.
Whey is a complex solution with extractable products that have uses in food technology.
Developing expertise
This section can be as large or as specialised as you wish.
(A) Which process produces the most whey?
Compare and measure the volume of whey production from different milks and processes eg casein production using vinegar versus using bacteria cultures.
(B) What is in whey?
 Compare whey obtained from different processes for colour, appearance, pouring ability and milk solids (using an evaporation procedure).
Possible teaching/assessment activities
Discuss the potential problem of whey waste in milk processing. For example waste disposal, pollution of land, changes to biological oxygen demand (BOD) in waterways.
Draw up a table to record quantities of whey produced from different processes.
Produce a report that identifies a range of tests to identify the components and the variation in
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Home > Focus stories > Mining milk > What to do with whey waste?
And / or
Students can explain the complex nature of whey and identify food technology products that can be developed from it.
The properties of whey could be utilised in the production of whey-based food additives.
Lactose intolerance has a significant impact on the population.
The lactose level of whey can be reduced using the enzyme lactase.
Although whey is rich in nutrients, its use as a fertiliser is problematic (it can increase the biological oxygen demand
(BOD) of the area).
 Carry out a density test (hydrometer), measure bacterial activity (Methylene blue or Resazurin), carry out food tests using dipsticks for glucose, lactose, proteins.
 Look up tables of whey composition.
(C) Explore the use of whey as a food additive
Investigate the occurrence and function of whey-based additives in foods containing gels and/or sweeteners.
Investigate the functionality of the whey that has been extracted, for example foaming ability, stability of foaming and emulsifying ability.
(D) Develop a method for reducing the lactose level of whey
Discuss the problems of lactose intolerance.
Investigate ways to remove lactose from milk products:
 A system can be set up and tested where lactose trickles through a column to produce a sweet glucose-galactose syrup. In this system, the lactose is digested (broken down) to glucose and galactose using an enzyme called Bgalactosidase.
 Fermentation can also be used to reduce the lactose content.
(E) Monitor the effects of whey spray on an area of land
 Compare plant growth in a sprayed and unsprayed area.
 Monitor the effects of whey on a measured volume of water over time (for example observe the effects of whey on the BOD of pond water).
 Develop a method for measuring increases in whey made using different processes.
Research a range of products containing whey components and compare their proposed properties against the properties of whey extracted in class.
Produce a pamphlet promoting the attributes of a lactose-reduced product.
Develop a system that breaks down lactose. Include methods for testing the endpoint (product) to provide consistency.
Data on plant growth, soil bacteria concentration and / or BOD levels on sprayed land; and comparison with data from unsprayed land.
©2005-2009 The University of Waikato www.biotechlearn.org.nz

Home > Focus stories > Mining milk > What to do with whey waste?
The community has varied reactions to the problem of whey waste and its disposal. bacterial numbers and activity of an area where whey has been sprayed (e.g. plate out bacteria from soil sprayed with whey; set up bacterial solutions and add methylene blue or Reazurin).
(F) Research the opinions of the community on the effects of whey waste disposal Produce a report that summarises the community’s reactions to waste disposal.
©2005-2009 The University of Waikato www.biotechlearn.org.nz