Oxidative quality 45 physical refining

Deodorizer distillate is the material collected from the steam distillation of oils. It is a mixture of free fatty acids (especially during physical refining) tocopherols, phytosterols and their esters, hydrocarbons, and hpid oxidation products. The quality and composition of deodorizer distillate depends on the feedstock oil composition and processing conditions. Tocopherols and sterols are the most valuable components that can be recovered from the distillate, and they are used in the nutrition supplement and pharmaceutical industries (201). Typical soybean deodorizer distillate contains about 33% unsaponifiable matters, of which 11% is tocopherol and 18% sterol (202). 

Some oils, like cottonseed oil, cannot be physically refined, as it requires an alkali treatment to remove the gossypol. For lauric oils and palm oil, on the other hand, physical refining is preferred in terms of both operating cost and refining loss. In the case of soybean and rapeseed oils, physical refining is suitable only for crude oils of a high quality, i.e., with a low degree of oxidation and a sufficiently low... 

The deodorized product, if properly pretreated and bleached, will be as stable and as high in quality as an alkali refined product. In some cases, a physically refined oil will show more flavor and oxidative stability than the alkali refined product. Physical refining has reduced processing losses by as much as 2%. As a result of eliminating alkali refining, many effluent problems are solved. Effluent is cleaner as a result of the elimination of soapstock production, acidulation, and reduced oil losses. The acidulation process accounts for the majority of the effluent from a refinery and is the most difficult to clean up. 

Quality of the oil starts from the seeds (39) for seed oils and from fruit palm (for palm oil and palmolein). Seeds that are physically damaged, insect-infested, moldy, too dry, or too moist produce poor-quality crude oil (40 3). Crude oil derived from such seeds can have high free fatty acids and oil oxidation products that inherently make the oil less stable, even after complete refining. 

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