Ensuring quality as well as quantity of protein raw materials

Multi-functional macromolecules

The Merriam Webster dictionary gives one definition of protein as: ‘the total nitrogenous material in plant or animal substances’.
Whilst this is true, proteins play a much more interesting and crucial role in everyday life than this rather boring definition portrays. Look at them superficially and you will see that they are macromolecules made up of amino acids. However, probe deeper and you then appreciate how important they are, as they fulfil many roles as functional materials. 

Depending who you ask you are likely to get a different view on what proteins are and what
they do:

• A biochemist might think of them as enzymes that carry out many functions as catalysts of biochemical reactions.
• A nutritionist might think of them as a key source of amino acids essential for maintenance of health and growth.
• A chef might think of them as useful kitchen ingredients, like egg white, that they transform into tasty deserts and clarify consommé with.
• A foodie might see them as the major (structural) component in a tasty piece of beef steak or a wafer-thin slice of fish in sashimi.
• An experienced pet food technologist will similarly recognise proteins as carrying out multiple functional roles. For example: 
  • Enzymes are used to produce palatants to create flavour.
  • Proteins provide amino acids to enable our puppies and kittens to grow and maintain a healthy, active life as senior dogs and cats.
  • Proteins provide structure and texture in dry and wet pet food, snacks and treats. Texture is an important driver of palatability.
  • Meats like liver are palatable raw materials in both dry and wet petfood.

In summary, proteins are a key component of pet food. However, there is a potential problem on the horizon. With a projected 9 billion human mouths to feed by 2050, development of consumer expectations and a growing global pet population, there is increasing pressure on the supply of sustainable protein, available to all.

Sustainable protein supply for all

There is much debate in society about the true cost of the supply of animal proteins due to the resources, especially water, required to produce 1 kg of animal protein. The Stockholm International Water Institute, for one, estimates that to produce 1 kg of chicken meat over 4,300 litres of water is required whilst beef production requires around 15,500 litres. 

Current protein production also brings with it other problems like land use and the production of methane, a greenhouse gas. Consequently, sustainability experts and scientists are actively developing novel, sustainable sources of proteins. 

These include materials based on cereals, insects and algae, and even ‘fake’, or lab, meat as a sustainable source of protein in the diet. 

Not all proteins were created equal

Whilst human rights advocates, like former US president Thomas Jefferson, might decree that ‘all men are created equal’, the same cannot be said when it comes to proteins and especially protein functionality. 

For example, while raw materials like chicken heads and feet (for use in wet) and feather meal (for use in dry) might look interesting in terms of their amino acid composition, they provide low functionality in terms of structure and texture.

Problems also occur when writing specifications for purchasing and quality assurance of protein-based raw materials. It is relatively easy to measure, specify and control protein content. However, it is much more difficult to predict and specify how a material will perform in pet food processes. How do we define and measure protein functionality in extrusion, say, in a meaningful and practical way?

Focusing on quality and safety

Protein content, being easily measurable, is typically a key selling specification parameter. Market price is often determined by protein level, with high protein level commanding high selling prices. 

The problem is that it is easy to trick conventional, traditional test methods into thinking the protein content is higher than it is. The global petfood industry and pet owners were shocked by an incident about a decade ago, when a number of pets died from eating petfood containing adulterated protein materials from China. Adulteration of wheat gluten and rice protein with the industrial plastic melamine tricked the protein analysis test into indicating a higher protein level than reality. Sadly, this criminal act resulted in the largest recall in the history of our industry and the needless deaths of many loved pets. It also highlights the problem of relying on a single analytical quality assurance test.

If there is anything good to come out of the melamine crisis, it is a refocusing on analytical methods, food fraud and supplier quality management in a complicated global supply chain. However, the challenge of fighting food fraud is ongoing and we must remain vigilant.

It is beyond dispute that we need to develop more, sustainable protein sources for future generations. The challenge for the industry, academics and the supply chain is to ensure that novel protein materials are safe, functional and of the quality expected by discerning 21st Century pet owners.