Vegetable oils decolorization

Castile soap is manufactured from olive oil, transparent soap from decolorized fats and liquid green soap from KOH and vegetable oils. Soaps are sometimes superfatted in that they contain some free fatty acid. 

Vegetable oils are refined through pressing/extraction, degumming, alkali deacidification, decolorization, and deodorization. Alkali deacidification byproduces soapstock. Acidulation of soapstock prepares acid oil which contains FFAs, acylglycerols, and other lipophilic compounds. It is reproduced currently as FFAs, which are used as raw materials for production of soaps, lubricants, and paints. But the demand for FFAs is almost in saturation. Hence, conversion of acid oil to BDF is expected to avoid an oversupply of the industrial FFAs and subsequent price decrease. 

Adsorption of liquids percolation The dehydration of liquids by stationary beds of adsorbent has already been mentioned. In addition, the colors of petroleum products, such as lubricating oils and transformer oils, and of vegetable oils are commonly reduced by percolation through beds of decolorizing clays sugar solutions are deashed and decolorized by percolation through bone char and many other liquid-treating operations use these semibatch methods. 

Mfnguez-Mosquera, M.I. et al.. Decoloration of vegetable oils and oleoresins with recovery of unaltered pigments, J. Am. Oil Chem. Soc., 68, 809, 1991. 

Other uses - Hormite clays are also used as thickeners in grease, polyesters, and vinyl plastisols, odor absorbents, bleaching (decolorizing) agents for petroleum, mineral, and vegetable oils, fdter aids, anticaking agents, pharmaceutical absorbents, acicular fillers in rubber (sepiolite), catalyst supports (sepiolite), and cosmetic/pharmaceutical thickeners and emulsion stabilizers. 

Adsorbents. Acid activated clays have been widely used to treat mineral, vegetable, and animal oils. The primary objective of such treatment is decolorization and, at least in the case of edible oil, to remove components that contribute to off-tastes. Typically the oil is filtered through a granular clay product or treated with finely ground clay and subsequendy filtered. 

DECOLORIZING AGENTS. A substance that removes color by a physical or chemical action. Charcoals, carbon blacks, clays, earths, activated alumina or bauxite, or other materials or highly adsorbent character ate used to remove undesirable colors (and often odors) front sugar, vegetable and animal fats and oils, and other substances. In a broad sense, decolorizing agents also embrace bleaches, which usually remove Color by chemical reaction. 

Activated clays and fuller s earth are used extensively for decolorizing fats and oils—animal, vegetable, and mineral. In a number of applications, they are used alone but for some fats and oils an admixture with activated carbon is required in order to attain a desired decolorization. Moreover, carbon will remove off-odors and tastes, whereas clays frequently impart a so-called earthy flavor and odor. Consequently, even when not needed for removal of color carbon is often admixed with clay to ensure freedom from any earthy flavor. 

Bleaching clay n. Clay that possesses decolorizing characteristics for use in refining of mineral, petroleum, vegetable, and animal oils from the spinneret hole involved. 

Oil bleaching - Aeid-aetivated and certain natural smectites are used to decolorize and in some cases to deodorize, dehydrate, neutralize, and filter mineral, vegetable, and animal oils. Products are qualified according to... 

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