Attached pictures of the Natural Cooking Oil
Caption 1:
Refinement Level - Oils are generally grouped into two camps: unrefined and refined. Oil flavor intensity is generally inversely proportional to processing. The first step in producing any oil is removing it from its fruit, nut, seed or grain source. All oil extraction processes involve heating the oil in some way. However, temperatures over 300 destroy the proteins and natural vitamin E in oils. Lower temperatures (in the 120 to 160 range) do not damage the oil significantly, but do reduce the yield, making good oils a little more expensive. It is essential to retain vitamin E in an oil because it prevents the oil from oxidizing. Oils with little vitamin E tend to go rancid quickly unless treated with antioxidant chemicals.
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Expeller-Pressed: These oils are obtained by squeezing the
seed, grain, or fruit at pressures up to 15 tons per square inch. The higher the
pressure, the more heat is generated. At extremely high pressures, the
temperature can exceed 300.Most oils are extracted by expeller pressing and
don't qualify as cold-pressed because friction heats them above 120. Still,
unrefined expeller-pressed oils retain most of their flavor, aroma, color and
nutrients.
Cold-Pressed: The term cold pressed theoretically means that an oil is expeller-pressed at low temperatures. However the term has no legal definition and is absolutely meaningless when used as an indication of quality. Olive oil, sesame oil, and peanut oil are really the only kinds that can be truly cold-pressed on any sort of large commercial scale. Olive oil is still extracted by the centuries-old process of stone-pressing, though these days it's usually done with hydraulic presses. Both techniques generate little heat, hence the term cold-pressed. They are the only substances that will easily yield their oil by simple, low-intensity pressure, which does not generate a great deal of heat. .True cold-pressed oils are prized. They contain minerals, phosphatides, and vitamin E and are high in trace nutrients.
Extracted: Extracted oils are invariably subjected to some sort of applied heat during processing.
Chemical or Solvent Extraction: The cheaper brands of oil (most regular commercial brands) generally use chemical solvents to extract the oil. A description of how the majority of oils are processed, or refined, is sobering. The oil is separated from its food source with hexane or other petroleum solvents and then boiled to drive off the toxic solvents. The oil is next refined, bleached, and deodorized, which involves heating it to over 400. The oil extracted this way still contains some undesirable solvent residues, while the amounts of many key nutrients (especially vitamin E) are significantly reduced. Antioxidants or preservatives such as BHA (butylated hydroxyanisole) or BHT (butylated hydroxytoluene) are then frequently added. The resulting product lacks flavor, aroma, pigments, and nutrients. All that can be said for such an oil is that it has an extended shelf life, a clear, uniform color, and an oily texture.
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