|Procedure and Chemical Reaction
|Removes free fatty acids, glycerol, carbohydrates, resins, metals, phosphatides and protein meal.
|The oil and alkali are mixed allowing free fatty acids and alkali to form a soap. The resulting soap stock is removed through centrifuging Cottonseed oil is also refined using a process called miscella refining.
|The oil produced thus has a lighter, more desirable colour.
|Eliminates trace metals and other colour bodies.
|Bleaching clays are used, which adsorb the impurities.
|Bleached oils are nearly colourless and have a peroxide value of near zero.
|Cottonseed oil destined to be used as salad oil is winterised so that it will not become cloudy when chilled.
|Oil is chilled with gentle agitation, which causes higher melting fractions to precipitate. The fraction which settles out is called stearin.
|Hydrogenation produces oil with the mouth feel, stability, melting point and lubricating qualities necessary to meet the needs of manufacturers.
|Treatment of oil with hydrogen gas in the presence of a catalyst results in the addition of hydrogen to the carbon-carbon double bond.
|It is a selective process that can be collntolled to produce various levels of hardening, from very slight to almost solid.
|It removes volatile compounds from the oil, the end product is a bland oil with a low level of free fatty acids and a zero peroxide value. This step als removes any residual pesticides or metabolites that might be present.
|Deodorization is a steam distillation process carried out under a vacuum. Cottonseed oil as it can be deodorized at lower temperatures, which results in more tocopherols (natural antioxidants) being retained.
|Deodorization produces some of the purest food products available to consumers. Few other products are so thoroughly clean as refined, bleached and deodorized oil.
|To rearrange or redistribute fatty acids on the glycerol backbone It can improve the functional properties of the oil.
|This is most often accomplished by catalytic methods at low temperatures. The oil is heated, agitated and mixed with the catalyst at 90°C. There also are enzymatic systems which may be used for interesterification.
|It does not change the degree of saturation or isomeric state of the fatty acids.