CO₂ Extraction vs Heat Processing in Marine Oils
By Kiran Dayaram
Once you begin to understand how complex marine lipids really are, another question naturally follows.
How do you extract them without destroying them?
This is not a small detail. In many ways, the extraction method determines whether the original lipid complexity of a marine organism is preserved — or simplified.
And like many things in modern food systems, the answer often comes down to heat.
Traditional marine oil production methods frequently rely on wet pressing or thermal rendering, where the raw material is heated to separate oil from tissue. Temperatures can reach 90–100°C or higher, allowing the oil to be released efficiently at industrial scale.
The process works well for producing bulk oils.
But lipids are delicate molecules.
Many of the most biologically interesting marine lipids — including polyunsaturated fatty acids (PUFAs) and certain phospholipid structures — are sensitive to oxidation and thermal degradation. Prolonged heat exposure can alter these molecules, break them down, or change the overall lipid profile of the final oil.
This does not mean heat-based extraction is inherently wrong. It has been used successfully in the food industry for decades.
But if the goal is to preserve the natural lipid spectrum of marine organisms, a different approach may be preferable.
That is where supercritical CO₂ extraction enters the picture.
Carbon dioxide behaves in unusual ways under pressure. When compressed and heated slightly beyond its critical point, CO₂ enters a “supercritical” state — a phase where it behaves partly like a gas and partly like a liquid. In this state, it can penetrate biological materials and selectively dissolve oils and lipids.
By carefully controlling pressure and temperature, CO₂ can extract lipids at relatively low temperatures — typically between 25°C and 45°C.
From a chemical perspective, this makes a meaningful difference.
Lower temperatures help reduce oxidation and thermal breakdown of delicate lipid structures. The resulting oil more closely reflects the molecular composition present in the original organism.
There is another advantage as well.
Carbon dioxide extraction does not rely on organic solvents. Once the pressure is released, the CO₂ simply returns to a gas and separates naturally from the extracted oil. The process leaves no solvent residues, and CO₂ extraction is widely recognized as GRAS (Generally Recognized As Safe) in food and nutraceutical processing.
For me personally, this technology is more than a processing step.
It has been a long-standing fascination.
I grew up on the west coast of New Zealand, surrounded by rugged coastlines and powerful marine ecosystems. Later, while working in Canada, I was introduced to advanced CO₂ extraction technologies and began to see their potential for working with natural products.
The idea that you could gently separate delicate compounds from biological materials using only pressure and carbon dioxide was remarkable.
It also aligned with something I have always cared about deeply: making better use of the natural resources we harvest, while minimizing waste and preserving the integrity of the original material.
Eventually, that curiosity turned into a project.
Back in New Zealand, in a warehouse in Christchurch, we began building and refining our own CO₂-based extraction system designed specifically for marine lipids. The goal was simple in principle, but technically demanding in practice: develop a process capable of capturing marine oils as close as possible to their natural state.
This kind of extraction is slower and more technically complex than conventional methods. The equipment operates under extremely high pressures and requires careful tuning to optimize yield while protecting the molecules we are trying to preserve.
But when the process works correctly, the result is something different from typical marine oils.
Instead of forcing oil out with heat, we are gently drawing it out with pressure.
The aim is not simply to produce oil.
It is to preserve the lipid architecture that nature built.
In many ways, this philosophy mirrors the broader idea behind our work.
The modern food system often simplifies things: refining, isolating, and standardizing.
Our approach is to start with complex natural materials — like marine organisms — and use technology carefully enough that the complexity survives the journey from ocean to capsule.
For me, CO₂ extraction is one of the most powerful tools we have for doing exactly that.