Homogenisation

Food processing is a core part of food sciences that aims to preserve food products for longer. One of the processes that we have in terms of food processing is the homogenisation step. Homogenisation is an important part, especially for the sector of dairy. Milk is an oil-water emulsion, and normally when it comes to milk processing, we would separate the cream from the milk, then we would pasteurise these two streams independently. And then we would do a process which is called standardisation. So the idea is that we produce different milk products with different fat content.

However, fat globules at this point are large, so we need to ensure that we decrease the particle size so that they can be stable for longer, this being part of the dispersion phase in the serum. That is why we use the homogenisation step as a process that aims to reduce the fat globules by allowing the milk to flow with high pressure into a homogenisation valve that will break these fat globules into much smaller ones. Of course, this process can also be extended into other products, such as solids. And there are other ways of homogenisation, like colloidal mill or extrusion. When it comes to these facilities, –so, this is part of an extended process, looking into a semi-continuous ice cream.

So after the homogenisation step, we’ll move into ageing and freezing. When it comes to milk production after the homogenisation step, we would move into packaging and distribution of milk. In terms of visual appearance of a homogenised milk, if you were to compare a non-homogenised and a homogenised one, you wouldn’t be able to see the differences with the naked eye. However, if you had the chance to put a drop under the microscope and compare the two milks, you will see that in the unprocessed milk, you will see big, larger fat globules floating about in the serum, whereas in the homogenised one, this will be far smaller.

Nowadays, due to modern life, we need to ensure that milk stays homogenised and it’s extended so that we can reach the consumers at any part of the globe. That is why we need the homogenisation step to ensure that this happens for an extended time period. So in terms of setting in the pilot plant, we will have an individual unit operation, as in the case of the homogeniser. However, on a commercial scale, this will be part of a continuous line that will follow on from separation and pasteurisation, and then will lead to packaging. Of course, the mechanisms and the objective are the same. The thing that changes is the volumes, which will be much larger.