Refined peanut oil is considered safe for peanut allergy sufferers by the FDA. Reactions to refined peanut oils that have been reported are generally mild. People with a peanut allergy are advised to stay away from crude peanut oils, or those called expressed, expeller pressed, cold-pressed, or gourmet. Because of the way these oils are processed, they may contain enough peanut protein to trigger an allergic response.
So, what is it about the refining process that makes peanut oil safe for an allergy sufferer?
Crude Oil: Pressed
Expressed oil refers to the substance extracted from a fruit, nut, or seed that does not evaporate when it warms and is made of fatty acids and their esters.
Expeller pressed oil is any oil extracted from seeds, nuts, or another source by a mechanical pressing processing. Although oils can be obtained using chemical means, many people feel expelling oil without using additives is a healthier choice.
Cold pressed oil is obtained by grinding or pressing seeds and nuts with either granite millstones or stainless steel presses. Though this process creates heat-generating friction, the temperature must remain at or below 120 degrees Fahrenheit, or 49 degrees C, for an oil to be called cold pressed.
Low processing temperatures allow oils to keep more of their natural aroma, flavor, and nutritional value. Sunflower, olive, and peanut oils are often created this way, and the peanut oil may retain enough protein to trigger and allergic response.
Refined Oil: Pressed, Steamed, Chemically Treated
Refined oils are extracted from peanuts or other product using both mechanical and chemical processes. The peanuts are steamed and crushed at high temperatures to extract the oil. The oil is then bathed in a hexane solvent (hexane is made by refining crude petroleum oil), and further refined by degumming, neutralization, bleaching, and deodorization.
- Degumming removes phosphatides from the oil by adding water and then decanting the non-water soluble phosphatides.
- Neutralization removes phospholipids, free fatty acids, pigments, and waxes by treating the oil with sodium hydroxide or sodium carbonate. This makes the oil lighter in color, less sticky, but more susceptible to oxidation.
- Bleaching treats the oil with activated carbon, fuller’s earth, or activated clays to remove any off-colored materials such as chlorophyll and carotenoid pigments. This process also promotes oxidation and removes some nutrients.
- Deodorization puts the oil under pressurized steam at temperatures of 500 degrees F or higher. This eliminates compounds that might cause an oder or funny taste in the finished product.
This refining process makes peanut oil safe for most allergy sufferers—there is little to no peanut protein, nor any other nutrients left after deodorization. Refining also makes oils unstable and prone to getting rancid more quickly.