Degumming

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The degumming is a process step in the refining of vegetable oil, the unwanted mucilage from the oil removed. It is used in the industrial production of vegetable oil in central oil mills that work with hot pressing and extraction .

Procedure

In classic (chemical) refining, the degumming process is divided into two phases. During the pre- degumming process (also known as lecithin extraction or delecithinisation), added water hydrates some of the phosphatides ( lecithin ) and the other mucilage . Oil-insoluble sludge forms, which is separated from the oil by separators . The sludge is added to the extraction meal or (especially in the case of soy, rarely in the case of rapeseed) processed into lecithin.

In addition to water and hydrogen, acids (phosphoric, citric, sulfuric acid) are often used for subsequent degumming . Non-hydratable phosphatides are destroyed and thereby hydratable. The hydration effect is also increased. The acid must be so strong that the phosphatides, but not the oil, are destroyed. Subsequent degumming is also possible by heating to 240 to 280 ° C (“breaking”), adding adsorbents (e.g. kieselguhr , fuller's earth , activated carbon ), and / or ultrafiltration .

With a biotechnological degumming process based on enzymes, the consumption of water, caustic soda, phosphoric and sulfuric acid as well as waste water and sewage sludge can be greatly reduced. The enzyme phospholipase A2 selectively splits off the fatty acid bound in the middle from the phospholipid molecule, whereby the remaining molecule becomes oil-insoluble and can be separated off.

Individual evidence

  1. ↑ H. Buchold, Lurgi Ag: Enzymatic phosphate removal from vegetable oils. In: Fat Science Technology / Fat Science Technology. 95, 1993, pp. 300-304, doi: 10.1002 / lipi.19930950805 .

literature

  • Josef Witzelsperger, Edgar Remmele: Examination of the suitability of processes for the reduction of deposits and ash-forming elements in rapeseed oil fuel in decentralized generation . In: Technology and Promotion Center in the Competence Center for Renewable Raw Materials (Ed.): Reports from the TZF . tape October 20 , 2009, ISSN  1614-1008 ( agrarplus.at [PDF]).