According to researchers, sustainable alternatives are needed to expand and improve omega-3 extract production, especially those contained in the 20 million tonnes (t) of fish processing waste produced each year.
“Approximately 5% of world fish oil production is used to extract its omega-3 contents for use as food ingredients and food supplements, with the remainder fraction being instead used for fish farming,” said the research team, led by Dr Mario Pagliaro, researcher at the Institute of nanostructured materials (ISMN) in Italy.
“Increasing the production of omega-3 derived from fishery by-products by recovering and transferring these important nutrients from the sea to the human food chain is a relevant opportunity to promote economic growth, environmental protection and human health at large.”
Omega-3 demand not being met
Along with the ISMN, the Institute of Biometeorology based in Firenze, Italy consider that with a daily dosage of 250 milligrams (mg), a daily production of 1625 t of Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) would be needed.
Current yearly production of EPA and DHA enriched oils does not exceed 85,000 t, putting into context the scope of the effort needed to meet tomorrow's demand.
Amongst the most recent advances in fish oil extraction, the team mention the use of antioxidants as well as protection techniques including microencapsulation to preserve omega-3 fatty acids from oxidation.
“Today, an increasing number of fish oil supplements are stabilized via natural antioxidants, especially of rosemary extract whose bouquet of phenolic compounds exerts high antioxidant activity with little aroma imparted from the natural antioxidant,” the study explained.
“For example, a combination of rosemary extract, tocopherols and citric acid in vegetable oil shows 4–8 times greater stability than the control.”
Encapsulation in gelatine or in whey gum is also widely used by industry to protect and deliver omega-3 fatty acids in a wide range of products.
The study mentions the efforts made by companies such as Ocean Nutrition in Canada, which use microencapsulated omega-3 concentrates obtained from Peru's sardines and Ecuador's tuna oil in protein-gum Arabic.
Dr Pagliaro and his colleagues also stress the need to protect fish population and ensure bio-diversity, highlighting the number of companies certified to comply with sustainability standards.
They pointed to the vast amounts of fish and seafood waste leftovers such as head, skin, trimmings and bones that were thrown away back into the sea.
Noticeably, a few companies already collect and recycle fish and seafood leftovers, converting them into valued fish oil and fishmeal.
German company, Lipromar purchases the by-products from local fish producers and produces fish oil and functional proteins for human consumption which are sold to omega-3 dietary supplement producers.
From a sustainability viewpoint, the use of organic solvents long-term would also need to be re-examined as cost and energy- intensive considerations threatened to substantially increase as demand was ramped up.
‘MAE process minimises energy required’
“The extraction process based on molecular distillation at ultralow pressures and high temperatures needs to be replaced by milder extraction processes based on green solvents,” the team warned.
“Affording the best extracts in terms of purity and lack of degradation but requiring high pressures in dedicated plants, microwave-assisted extraction (MAE) with d-limonene, an excellent biosolvent for the extraction of fatty acids, is proposed herein as an economically viable alternative.
“At the end of the extraction, nontoxic and highly degreasing d-limonene solvent obtained from citrus peels, is fully recovered via hydrodistillation.
“Furthermore, the short duration of the MAE process (several minutes rather than several hours) today perfectly suited for industrial scale-up, minimizes the energy required.”
The study concluded with recommendations urging companies and governments to act in building new extraction plants based on these sustainable chemistry technologies.
It also wanted to see the closing of the materials cycle and to waste generation that creates environmental pressures when disposed of in landfills or discharged at sea.
“Companies extracting omega-3 from fish oil will accompany improvements in sustainability along with advances in the ability to communicate the value of their products.
“Altogether, we argue in conclusions, said improvements will make of the sustainable fish-oil based omega-3 sector a pillar of the emerging bioeconomy.”
Source: Sustainable Chemistry and Pharmacy
Published online ahead of print: doi.org/10.1016/j.scp.2017.03.001
“Enhancing and improving the extraction of omega-3 from fish oil.”
Authors: Rosaria Ciriminna, Francesco Meneguzzo, Riccardo Delisia, Mario Pagliaro