Enzymatic degumming

The first enzymatic degumming process to be used industrially was the EnzyMax (R) process that was launched in 1992; it used porcine phospholipase A2 (PLA2). Subsequently, various microbial phospholipases (PLases) with different specificities have been developed. They have the advantages of being kosher/halal and of having a non-limited availability and lower cost. The first of these microbial enzymes were the phospholipases Al (Lecitase (R) Novo and Ultra) and more recently, a phospholipase C (Purifine (R)) and a lipid acyl transferase (Lyso Max (R)) with PLA2 acitivity have also become available in commercial quantities. These enzymes have different specificities. The Lecitases (R) and the LysoMax (R) enzymes catalyse the hydrolysis of all common phosphatides and differ in this respect from the Purifine (R) enzyme, which is specific for phosphatidyl choline and phosphatidyl ethanolamine. These phosphatides are hydrolysed to oil-soluble diacylglycerol and water-soluble phosphate esters. Since these diacylglycerols remain in the oil during refining, they contribute to the oil yield. That also holds for the sterol and stanol fatty esters formed as a consequence of the phosphatide hydrolysis catalysed by the LysoMax (R) enzyme. In addition, all enzymes cause less oil to be retained by the gums by decreasing the amount of gums and/or their oil retention, which also contributes to an improved oil yield. On the other hand and contrary to common belief, the enzymes are incapable of catalysing the hydrolysis of non-hydratable phosphatides (alkaline earth salts of phosphatidic acid) under industrial conditions. Consequently, the industrial enzymatic degumming step has to be preceded by a chemical degumming step to arrive at a degummed oil with a sufficiently low residual phosphorus content that can be physically refined. Accordingly, it might well be preferable to limit the oil treatment to said chemical degumming and produce oil with a low residual phosphorus content and gums, and then treat the gums separately to recover their fatty matter, whereby this recovery can be enzymatic or chemical.