The research, said to be the first to compare differences of mussel size and sex and geographical region on omega-3 composition, has important implications for companies extracting omega-3s from the mussels as a potential alternative to fish oils.
Co-author of the new study, Candida Savage from the University of Otago, told NutraIngredients.com: "We see the results as providing useful information for companies that already have commercial products such as Lyprinol on the market, or for those companies looking to expand their product portfolio into the nutraceuticals market."
The NZ green lipped mussel, ranked among the top 'eco-friendly seafoods' according to the US environmental agency Blue Ocean Institute's list, is already used a source of nutraceuticals.
The extract, a rich source of iron, betain, and glycoaminoglycans (including chondroitin sulphate) has gained a reputation amongst consumers as a natural product with anti-inflammatory properties - an effect that has been attributed to a body of science to its lipid factions.
The Greenshell, Green Lips and Greenback mussel trademarks are owned by the New Zealand Mussel Industry Council (NZMIC).
The majority of green-lipped mussel extract suppliers offer material that retains, to a greater or lesser degree of standardisation, the mussels' natural nutrient profile.
There are also a small number of products that contain high levels of stabilised lipids, such as Lyprinol marketed by Pharmalink, which is said to be "125 times more potent than the original freeze dried mussel powder."
However, a broad range of processes and different efficacies can be found amongst green lipped mussel extracts, and while the NZMIC is aware of this the onus is said to be very much on the industry to pull together and set standards.
The new research, published in the journal Aquaculture (Vol. 261, pp. 430-439), looked at the omega-3 content of the mussels and found that the commercially important omega-3s, DHA and EPA, made up about 75 per cent of the total polyunsaturated fatty acid (PUFA) content of the mussels.
During the winter months the omega-3 content decreased, report the authors, Alexandra Taylor and Candida Savage, probably linked to a decrease in the PUFA-rich phytoplankton as food.
The researchers also report that there were no significant differences in the total PUFA content between large male and female mussels.
DHA and EPA levels were found ovary between geographical regions, with mussels collected in the colder waters off Stewart Island having higher EPA levels, while mussels collected in the warmer waters in the Marlborough Sounds had higher DHA levels.
They also state that the optimal harvesting conditions are spring "when mussel condition and omega-3 content peak for large mussels," they wrote.
"The results therefore should provide valuable information for the industry as to the optimal harvesting conditions," said Savage.
Fears about dwindling fish stocks, coupled with the putative risk of pollutants from oily fish, have pushed some in academia and industry to investigate the extraction of omega-3 from alternative sources.
"While the total lipid content of the GLM is relatively low compared to some fish species, the n-3 fatty acid content (15-22 weight per cent of oil) is particularly high for shellfish. Therefore they provide an excellent and sustainable source of omega-3 while fish stocks are experiencing significant declines," Dr. Savage told NutraIngredients.com.
Companies such as Martek Biosciences and Lonza are already offering algae-derived omega-3 DHA as a dietary supplement.
"The question of omega-3 content between shellfish and algae requires further research," said Dr. Savage.
And only recently, this website reported on research by BASF, Du Pont and others into producing a sustainable and pollutant-free source of EPA as well as DHA from crops such as soybeans and Brassica.