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									                                                                                             428 inform July 2010, Vol. 21 (7)




        Degumming revisited
        2 010 PHO ENIX
        101st AOCS Annual Meeting & Expo




        Albert J. Dijkstra                                                           The use of PlC as a degumming agent
                                                                                   can increase the oil yield, especially for
        The following article is based on the address given by Albert J.
        Dijkstra, the 2010 Timothy L. Mounts Award winner. His address         high-phosphatide oils such as soybean oil
        was given at the 101st AOCS Annual Meeting & Expo, held in
        Phoenix, Arizona, USA, May 16–19.                                         that has not yet been water-degummed.
                                                                              MPL (AB Enzymes, Darmstadt, Germany), and additional microbial
        In 1992, during the AOCS World Conference in                          enzymes have been developed. One of these is Purifine®, a phospho-
        Budapest (Dijkstra, 1993), I launched the enzy-                       lipase C (PLC; Verenium Corp., Cambridge, Massachusetts, USA).
        matic degumming process EnzyMax® on behalf                            As indicated in Figure 1, it catalyzes the hydrolysis of the phosphate/
                                                                              glyceryl bond in phosphatidylcholine (PC) and phosphatidyletha-
        of lurgi, the company that had developed this                         nolamine (PE), the major phosphatides in most vegetable oils. This
        process. I reported that I had measured low resid-                    hydrolysis yields diglycerides and phosphate esters of choline and
        ual phosphorus and iron contents in the enzymat-                      ethanolamine, respectively. These diglycerides are not removed
                                                                              during subsequent refining processes, and since the phosphate esters
        ically degummed oil samples lurgi had given me.                       do not retain any triglyceride oil, the use of PLC as a degumming
        So I could not but conclude that the oil would yield                  agent can increase the oil yield, especially for high-phosphatide oils
        good quality oil on physical refining and that the                    such as soybean oil that has not yet been water-degummed. For these
                                                                              oils, the yield increase amounts to 1% of oil for every 500 ppm of
        EnzyMax process would therefore compete with                          phosphorus present in the crude oil. Purifine PLC does not catalyze
        my own acid refining process TOP (Dijkstra and                        the hydrolysis of other phosphatides than PC and PE, so it is not
        Van Opstal, 1989). however, by repeating in this                      capable of providing an oil that is so low in residual phosphorus and
                                                                              iron that it can be physically refined.
        presentation what lurgi had told me, I also misled                          Another enzyme that is used in degumming is LysoMax®, a lipid
        the audience by stating that the citrate buffer was                   acyl transferase with PLA2 activity (LAT; Danisco AS, Copenhagen,
        added to the oil as such, whereas
        in actual practice, a concentrated
        citric acid solution was added first
        and a dilute caustic soda solution
        was added quite some time later.
        In 1998, when presenting a paper
        on degumming at the AOCS Annual
        Meeting & Expo in Chicago, Illinois,
        I rectified this statement by describ-
        ing the EnzyMax process as an “acid
        refining process in disguise.”
            Since that time, the porcine phospholipase
        (PLA2) used in the original EnzyMax process
        has been replaced by microbial enzymes such
        as the phospholipase A1 (PLA1) enzymes
        Lecitase® Novo and Ultra (Novozymes, Bags-
        værd, Denmark) and the PLA2 enzyme Rohalase®        FIG. 1. Chemical structure of various phosphatides.




inform JULY 10.indd 428                                                                                                                        7/6/10 5:14:33 PM
                      inform July 2010, Vol. 21 (7) 429
                                                                                                              Award Address

                                                                                   coalesces and the rate of reaction at the interface decreases. For an
                                                                                  
								
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