Discarded tuna byproducts get new life as mealworm feeding boosts unsaturated fatty acids by 84%

Tuna byproducts that were once discarded may soon find new life as high-value food and feed ingredients. Researchers have succeeded in raising unsaturated fatty acid levels by 84% using an eco-friendly mealworm-based process while keeping protein content intact.

The Korea Institute of Ocean Science and Technology (KIOST) announced Wednesday that a research team led by Heo Seong-yeong of its Jeju Biotech Research Center, working with a team led by Kwon Jun-pyo, a professor at Ajou University, has developed a technology that uses tuna byproducts as feed for mealworms.

The research team fed mealworms tuna spine byproducts generated during tuna processing, then analyzed changes in the insects' nutritional composition. Protein content held steady at around 45%, while fat content rose from 26.9% to 32.5%.

Particularly notable was an 84% increase in unsaturated fatty acids — including oleic acid and linoleic acid, which are known to help improve blood cholesterol levels and boost immunity — compared with mealworms raised on conventional feed.

Antioxidant performance also improved. Mealworms fed the tuna byproducts showed roughly twice the free-radical scavenging capacity of those on conventional feed, and cytotoxicity tests confirmed their safety.

Rather than using chemicals to pretreat tuna bones, the method lets mealworms consume the remaining flesh and bone marrow directly. The approach reduces disposal costs and environmental burden while enhancing the nutritional value of the mealworms, offering a potential upcycling model for fishery byproducts.

"Byproducts from the sea are a resource with strong untapped potential," Heo said. "Starting with tuna, we plan to expand our research to a wider range of fishery byproducts and increase the utilization value of ocean resources."

The findings were published in the international food science journal Food Chemistry: X. Building on the results, the research team plans to extend the approach to various other fishery byproducts and continue developing eco-friendly biomaterial industrialization research aimed at achieving zero waste.