|
The quality characteristics of fats and oils, or in the foods with a high content of fats and oil always involve avoiding oxidation, which is the most significant deterioration mechanism for these products.
Oxidation in this discussion is specifically referred to as the chemical reaction of atmospheric oxygen attacking the fat acid chains of triglyceride molecules. The oxygen attack can take place at ambient temperatures or below, such as during normal storage of oils or finished food products. It can also occur at elevated temperatures during deep fat frying. In order to protect the oil and improve oil stability, oxygen should never come in contact with the product from the very beginning of the production process.
Nitrogen is a chemically inert gas that does not interact directly with the product. It is used to displace atmospheric air, and thus oxygen and water vapor, to avoid oxidation. The oxygen is replaced by nitrogen using two different techniques - sparging to remove dissolved oxygen and blanketing to assure the absence of oxygen in the headspace. The use of each process will obviously depend of the type of product and the processing stage. For example, nitrogen blanketing is beneficial for the holding tanks used for intermediate oils and the storage tanks for crude and finished oils.
Another technique, widely used in the fats and mayonnaise industry, is referred to as fluffing. The main objective is to change the texture of the product. It is used in fats for bakery products, assuring the desired density and the presence of an inert gas instead of air. |
