Turning food waste into wealth

Avocado seed powder to make snacks, fish waste skin for wound healing, and bioactive compounds made from brewer's spent grain - Claire Concannon visits a food lab at AUT turning food waste into wealth.

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

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.

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.

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. …

Go to this episode on rnz.co.nz for more details