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When fats and oils are used in the production of other food products that will require high temperatures, for example during frying or baking, nitrogen use is recommended to protect oil stability and minimize oil oxidation. Linde has developed a process called ATMOFRY™ to protect the oil during the continuous industrial frying process. Besides assuring the oil quality, it provides longer use of the frying oil.
Among the large number of food products fried in oil are coated foods such as fish filets, fishsticks and shrimp. Frying usually takes place at temperatures between 320°- 400°F. Unsaturated fats, usually a major ingredient in frying oils, are particularly sensitive to oxidation at these high temperatures. The oil becomes darker and more viscous. It begins to smoke and emit unpleasant odors that can also be reflected in the quality of the food being prepared. The build-up of oxidation products gives rise to a rubbery, hard-to-clean film on the frying surfaces, diminishing the heat transfer rate of the frying equipment.
Linde's technique for inerting the oils is based on a technology widely used elsewhere in the food industry. Nitrogen is injected in the form of micro-bubbles through a sintered stainless steel diffuser into the frying oil. This is done in the in-feed oil pipe for continuous fryers or in the fryer itself (in the case of batch fryers). The nitrogen micro-bubbles strip the oxygen dissolved in the oil. This prevents further deterioration through oxidation. |
