Turning processing discards into high-value compounds for the food, medical, pharmaceutical and nutraceutical sectors.
That’s the focus of Marine Institute (MI) researchers who are examining cost-effective and environmentally sustainable ways for fishing and aquaculture industries to maximize the use and value of so-called “waste.”
Some examples of discards are chitin from shrimp shells, polyunsaturated fatty acids from farmed salmon and collagen from sea cucumbers.
Dr. Deepika Dave, a research scientist with MI’s Centre for Aquaculture and Seafood Development (CASD) leads a team of technologists, graduate students and post-doctoral fellows at the centre’s bioprocessing research unit.
“We are an industrial response unit and we are working with industry partners on proof-of-concept and pilot-scale projects,” said Dr. Dave. “We want to help the local industry take it to the next step.”
CASD operates two fully equipped facilities: a bioprocessing research laboratory and pilot plant facility.
“We validate our results at the lab scale and then take it to the pilot scale, so that is the uniqueness that we have within this research group.”
Shrimp-chitin project
The researchers are developing a mechanical-chemical-enzymatic process to extract chitin, chitosan, protein and calcium carbonate from shrimp shells. Usually discarded, these shells comprise up to 70 per cent of the crustacean.
Dr. Dave says traditional commercial processes to extract chitin and chitosan are chemically intensive.
“The method we have developed is very novel and we have reduced the chemical load by 82 per cent,” she said
Earlier this year, the shrimp-chitin project landed a $250,000 grant from the Weston Foundation’s Seeding Food Innovation program to validate its processing technologies and produce chitin on a pilot scale. The Weston grants provide seed funding for interdisciplinary research or technology development that help accelerate solutions to sustainable food challenges.
Valuable fatty acids
Dr. Dave says the discarded parts of farmed salmon can be as valuable as fillets sold in grocery stores because they are rich in polyunsaturated fatty acids (omega-3 and omega-6), protein and marine calcium.
“We found omega-3 levels to be much higher than in the main product. They are more concentrated in other parts of the fish than the fillet, which we are using for human consumption.”
Those high levels vary depending on the season, location of the salmon farm and fish diet.
“We have to pay attention to quality as we do with the main food product because this has more value than the fillets.”
Dr. Dave says the goal is to provide a complete environmental solution for extracting all three compounds from discards, such as bones, skin and heads. Part of the challenge is ensuring a high standard of preservation and storage for the manufacture of food-grade products.
“These discarded parts are prone to degrading quickly because of the high polyunsaturated fatty acids. We have to pay attention to quality in the same way as we do with the main food product because this has more value than the fillets.”
In the lab, the CASD team has also demonstrated that overall salmon waste can be as low as 1.5 per cent. Dr. Dave says there is more to come: they are currently scaling the research up from the laboratory level to the client level.
Sea cucumbers
Sea cucumbers inhabit the seafloor of deep oceans all over the world.
In the Atlantic Canada fishery, meat from the leathery skinned, cylindrical creature is exported, fresh or dried, to primarily Asian markets.
CASD is developing a bio-processing strategy for the full use of sea cucumber, including its body wall, flower and internal organs that are high in protein and collagen.
About 70 per cent of the body wall protein consists of collagen, an essential building block for skin, bones, muscles and joints.
“It’s a unique creature – it has very unique properties compared to other marine species,” said Dr. Dave, who received a Natural Sciences and Engineering Research Council of Canada Discovery grant in 2015 for her sea cucumber research.
“We are working on extracting the bioactive compounds it contains because not much work has been done on this species in the Atlantic region.”
