Pet food and beyond - utilising Abalone waste

The unique biochemical composition of abalone is providing clues to potential new uses for waste and transforming viscera, blood and shells into value-added products.

By Catherine Norwood

Abalone processing, once primarily a source of waste, is now revealing valuable byproducts. Gut materials, blood and shells offer untapped potential for diverse applications, from health and food products to fertilisers and packaging.

Smit Shahu (R) and Tharukshi Hansika (L), holding a product using abalone shell, a byproduct to partially replace plastic in conventional packaging. This reduces plastic usage, increases biodegradability, improves physical properties of packaging and reduces protein breakdown during storage. Credit: Alexis Wing Huen Chung, Curtin University

The Abalone Council Australia, FRDC and the End Food Waste Cooperative Research Centre (CRC) are partners in an initiative to map waste streams and identify economic opportunities (2020-119).

This could help Australian abalone fishers and processors to reduce waste and the related costs of disposal. It could also boost incomes from declining harvests, which have dropped over the past two decades from more than 5000 tonnes a year to around 2000 tonnes in 2021-22.

Mapping waste streams

Dr Janet Howieson at Curtin University is leading the research into abalone waste opportunities. She says the first stage has been to map the volumes and locations of the processing waste streams for commercially fished abalone in New South Wales, South Australia, Tasmania, Victoria and Western Australia.

Abalone are about 33 per cent edible meat, 33 per cent shell, 25 per cent viscera and six per cent blood.

Based on 2019 production figures, the research found a total of 1,196 tonnes of "by-product" - shell, viscera and blood - was generated from fished and ranched abalone nationally.

Of this, 38 per cent was used in current and potential products such as pet foods and animal feeds, sauces, beer, fertiliser, compost and nutraceutical and food trials. Another seven per cent was stored for future use and trials. Thirty-one per cent was disposed of as waste on land, and the remaining 25 per cent was disposed of at sea - a practice permitted in South Australia and Western Australia.

Biochemistry of viscera

The second step in the project has been to identify the biochemical composition of abalone viscera from different species and locations around Australia.

Nutritional and antioxidant data has been completed for all four commercial species: Greenlip Abalone (Haliotis laevigata), Blacklip Abalone (Haliotis rubra), Brownlip Abalone (Haliotis conicopora) and Roe's Abalone (Haliotis roei).

Janet found that when scientists broke down the internal organs of animals into smaller pieces using special enzymes in a lab, the organs became even better at fighting off harmful substances.

Pictured: Abalone Viscera Credit: Alexis Wing Huen Chung, Curtin University

"Because of the amino acid, antioxidant and anti-inflammatory profiles, we've also done some work looking at the viscera as a functional ingredient in pet foods, and I think that's a real opportunity.

"We've made abalone stock, which still needs some refinement to address a bitterness in the product. And we've completed a successful composting trial."

Blue blood and shell opportunities

The project team has also completed a compositional analysis of abalone blood and shells to identify market opportunities.

To improve the blood's antioxidant properties, scientists plan to break it down into smaller molecules. They also want to find new ways to keep the blood fresh after it's harvested.

Abalone blood, which is blue by nature, is hypothesised to have strong bioactivity because Abalone doesn't have an established immune system, relying on their blood to protect itself. Credit: Alexis Wing Huen Chung, Curtin University

She says abalone shell also has an unusual mix of different types of calcium carbonate, "an unexpected finding" which opens possible new opportunities in the human health field.

"More practically, we're looking at whether it can be added to PLA plastic (made from plant-based polylactic acid) to make it tougher, cut down plastic usage, increase biodegradability and extend the shelf life of packaged goods," says Janet. "Trials with Atlantic Salmon mince look quite promising so far."

Curtin University Student, Annette Paul, applying an edible coating to Salmon, which was found to extend shelf life. Credit: Alexis Wing Huen Chung, Curtin University

Future capacity

An important part of the project has been the sponsorship of two post-graduate students, building capacity for future research. Lynne Loo undertook the waste stream mapping and management analysis as part of her Master of Business degree.

Alexis Chung is studying the guts of animals. She's breaking them down into smaller parts and testing how they might be used for medicine or other purposes. She's also growing skin cells in a lab to see how they react to the gut material. Curtin Masters of Food Science Technology students have also participated in the research as part of their studies.  

FRDC Senior Research Portfolio Manager Dr Chris Izzo says building this post-harvest research capacity will be important to support the abalone sector and future initiatives across the seafood sector more broadly.

"Abalone Council Australia is being proactive in looking at how to fully utilise reduced harvests from wild caught resources," says Chris.

"If you're going to harvest something, whether that's abalone or another species, you want to get the most out of it.

"Working with the End Food Waste CRC, and getting shells included in the project, has been a positive step. This project is helping to raise awareness of waste as a resource, which aligns with FRDC's support of circular economy initiatives."

Chris says FRDC hopes to see more fisheries and aquaculture sectors consider post-harvest opportunities to maximise the use and value of their harvests.

Related FRDC Project

2020-119 New Opportunities for Abalone Processing Waste

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