Oxidation means mainly the chemical reaction with the airborne oxygen that attacks the fatty acid chains in the triglyceride molecules. Oxygen attacks may take place both by ambient temperatures and by lower temperatures which are typical for normal oil or final food product storage. They also may occur by increased temperatures or during processing or frying in oil.
To preserve oil and improve its stability, products may not come in contact with oxygen from the very beginning of the production process. Nitrogen usage in the food industry is an effective alternative the importance of which always grows due to the worldwide trend to replace the physical and chemical preservation methods by milder ones.
Nitrogen is an inert gas that does not react directly with the product. It is utilised for replacement of airborne oxygen so that product oxidation is avoided. There are two different techniques how to replace oxygen by nitrogen:
Sparging – nitrogen is brought directly into oil with the target to remove solved oxygen
Blanketing – the free space above the oil is filled with nitrogen
Besides these two methods, there is another gas technique which is often utilised by the fat and mayonnaise production; it is called foaming. The main task of this technique is to achieve a product texture change. It is mainly used for bakery products; the desired fat density is reached by inert gas which prevents the air presence in the fat.