Controlling rancidity is important in all edible oils, but is especially important for delicate oils, such as cod liver oil. A common misconception about the oil we produce is that is rancid due to the fermentation process, is in this post I’d like to take the opportunity to show how we protect against rancidity.
Rancidity refers to the breakdown or damaging of fats. There are different types of rancidity, but in terms of omega-3 fats, oxidative rancidity/ free radical rancidity is the most important to control. This is because oxidative rancidity damages the important chemical structures that make omega-3 fatty acids healthy.
In order for oxidative rancidity to take place, the fats must be exposed to something chemically reactive that will break the chemical bonds in omega-3 fats. The most common chemical is atmospheric oxygen. The process of oxidative rancidity is accelerated by heat and exposure to direct sunlight.
So, to avoid oxidative damage, the key is reducing exposure to the air, light, and heat at all stages of the process.
How Armorica avoids rancidity
Our fresh cod livers are delivered in vacuum-sealed packages and transported in dark, temperature-controlled vehicles which are designed for delivering delicate fishery products. Upon delivery, the livers are inspected and put into our custom-designed fermentation vats (along with salt). The small air space at the top of the vats is flushed with nitrogen (which is unreactive) and sealed. The vats have a one-way airlock to prevent any air from entering the vat.
During the fermentation period, the nitrogen will be replaced with gases produced by the bacteria, which is typically carbon dioxide, which is also chemically inert.
Once the fermented oil is ready, it is siphoned out of the vats and passed through our proprietary plant fibre filters (to remove environmental toxins) in a vacuum. Once filtration is done the oil is ready to mix with organic lemon oil, for our fermented cod liver oil liquid product, or stored in nitrogen-flushed vessels to be encapsulated.
The entire process, from start to finish has steps to avoid contact with oxygen.
Does it work?
We of course lab test all our batches before we sell them for quality and safety. For rancidity, the primary marker is the peroxide value, with the upper limit being 5 meq/kg of oil. Our most recent batch of fermented cod liver oil tested the following peroxide value:
From the lab results, you can see that fermented cod liver oil can be produced with very low rancidity, providing the correct measures are taken during its production.