Rights: The University of Waikato Published 15 July 2009 Download

Fish oil oxidises easily, causing a fishy taste and smell. Scientists at Riddet Institute have created a way of coating tiny droplets of fish oil to prevent oxidation, so the oil can be added to food. This process, called microencapsulation, is described here.


Dr Harjinder Singh (Riddet Institute)

Microencapsulation is the kind of science of packaging. You have a very sensitive compound, a very active compound within a secondary material, and then you create this new structure, which is a few microns inside, that is why it’s called microencapsulation. So you are encapsulating the active ingredient within a shell or a wall, and the whole diameter of that shell or that particle is a few microns.

In the case of the fish oil, what you do is you take oil and water, mix it with a high-speed homogenisation and that will create small droplets of fish oil. Then the challenge is whether you can coat those small droplets of oil with some protective material so they don't infiltrate, they don't oxidise, and they remain stable in a range of food environments. And that is the key challenge.

We take good quality fish oil and then we have some proteins, which we are using as raw materials. So it’s simply just mixed together with standard homogenisation equipment, which is common in the food industry. And this wall is created around the oil droplet. The key technical challenge was how to create that wall. It’s not a simple protein solution, it’s a very complicated mixture of proteins, and those proteins have been selected so they can actually impart some antioxidant function within that stabilising layer if you like. So basically, once we created that layer and then we tested the protection ability of the layer against oxidation of the oil, and hence it creates this novel technology.

You're looking for stability of the emulsion itself, so the whole emulsion state fully dispersed is stable to heating and storage. So you’re looking for that property in that layer, then you are looking for the antioxidant mechanism built into those stabilising layers as well. In terms of actually making it, it’s quite simple. The IP is in the stabilising layer.