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The terms butter, oil and fat have become generic, as opposed to their use to describe chemical structures. The difference between the terms is defined by a physical, not a chemical, property. Specifically the salient property is the titer point. Fats have a titer point of over 40.5ºC, while oils have a titer point of below 40.5ºC and butters have a titer below 40.5ºC but above 20ºC.
Naturally occurring butters (NOB) include shea butter, coco butter and mango butter. These materials are native in plants and are butters due to the composition of the oil extracted from the plant. Unlike oils, which are liquid because they have a have a high iodine value, these butters have a low iodine value. This lower level of unsaturation results in compositions that are solid at room temperature.
There are a finite number of naturally occurring butters provided by nature. These products tend to be expensive and may not give the range of cosmetic properties desired by the formulator. This has resulted in the modification of oils to make soft solids at ambient temperatures, resulting in naturally derived butters (NDB), where natural oils are modified to form a solid.
NDB can be made by adding materials to naturally occurring butters to modify the oils to make them butters. This addition dilutes the oil by the concentration of compound added to affect the change from oil to butter; the addition does not chemically modify the oil and consequently, cosmetic properties are observed in the oil.
Chemically modified butters (CMB) are those butters in which a naturally derived oil is transformed by chemical processes into a new composition, different from the original composition.This process is known as hardening of oils in the foods industry. CMB can be made using several methods that are used to make natural oils with their inherent concentration of unsaturated species solid (oleyl and linoleyl). One of the most common methods of chemically modifying butter is the hydrogenation of native oils, with the conversion of the unsaturated oil into a saturated oil.