Avocado seed powder and puffy snacks. Photo: Claire Concannon / RNZ
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Food is usually a no-no in a science lab, but this lab at the Auckland University of Technology is different.
One fridge is labelled ‘beer research’. There’s a drawer full of stick blenders, and a coffee machine.
“Well, it is a food lab,” says senior lecturer Dr Rothman Kam. “It would be quite sad if you do experiments and were not able to eat the food that you make.”
Food scraps to snacks
Extrusion machine for making puffy snacks. Photo: Claire Concannon / RNZ
Rothman and his food science lab group are interested in turning food waste into high value products (a process called ‘food waste valorisation’).
For example, tonnes of avocado seeds are a waste product of making avocado oil. Rothman and his team have set their sights on transforming seeds into snacks.
They’ve worked out a method of blending the seeds and processing them to make them fit for human consumption, resulting in an avocado seed powder.
This powder can then be added to breads or biscuits, or used with other grains to make puffy snacks.
Arti-fish-al skin for wound healing
A second project, led by PhD candidate Edward Quach, is investigating the use of fish waste products to create artificial skin. This skin can be loaded with drugs to help burn victims heal faster.
Edward Quach with the ground fish waste and artificial skin prototype. Photo: Claire Concannon / RNZ
While the method of using fish gelatine in this way isn’t new, Edward is trying a novel technique that bypasses the need to extract the gelatine, and instead goes straight from the freeze-dried ground-up fish waste to the jelly-like skin.
A second life for spent grain
The lab’s ‘beer research’ focuses not on the alcoholic drink, but on the spent grain generated in the beer brewing process.
PhD candidate Ha Minh Quoc uses a freeze-drier to remove any moisture from the brewer’s spent grain. Once he has dried out the grains, and ground them to a powder, he adds bacteria in. The bacteria (and the enzymes they contain) chop up proteins found in the grain, producing molecules with bioactive properties.
Ha Minh Quoc in front of the freeze-drier containing brewers' spent grain. Photo: Claire Concannon / RNZ
These bioactive molecules are small bits of protein (peptides) that can carry out many different important functions in our cells. For example, bioactive peptides might help fight off germs, reduce high blood pressure, lower blood fats, act as antioxidants, or help ward off obesity, diabetes or ageing.
Bioactive peptides are found naturally in fermented foods such as tempeh, yoghurt and whey protein – but they are also added to different food or pharmaceuticals to enhance them. Early investigations done in the lab have shown that some useful bioactive peptides can be made using the brewer’s spent grain.
The work of PhD candidate Ha Minh Quoc in transforming brewer spent grains into high-valued food is part of the Catalyst grant “Wood hemicellulose - a new coating material to create novel functional food ingredients” (CSG-AUT2102). This AUT Centre for Future Foods’ project is led by Dr Thao Le and in collaboration with Edith Cowan University, Australia and University of Helsinki, Finland.
Listen to the podcast to visit the lab and learn more about how the team are converting food waste into high-value products.
Learn more
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Why do somethings taste good together, and others not so much? Listen to Justin Gregory’s The recipe for food pairing to find out.
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Eating is a sensory experience, as Alison Ballance learned in How sound influences the taste of food.
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Bioengineers at the University of Otago are also using 3D bioprinters to investigate how to promote wound healing.
