Application of enzymatic degumming on vegetable oils refining

Enzymatic degumming is a novel vegetable oils degumming process and has many advantages compared with conventional water or acid degumming methods. Degumming oil can satisfy the requirement for physical refining, reduction in the amounts of water used and wastewater production and less energy consumption, higher refined oil yield can also be achieved in the enzymatic degumming. So it has attracted much attention from the global edible oil processing industries. With the development of enzymatic degumming techniques, many phospholipases (A1, A2, B and C) have been used for vegetable oil degumming. Phospholipases A1 (Lecitase Ultra) is most widely used in various vegetable oils' degumming and shows extensive applicability and good prospects. Phospholipases B (PLB) can hydrolyze phosphatidylcholine (PC) and phosphatidylethanolamine (PE), which are main components of phospholipids in the oil, into glycerylphosphorylcholine (GPC) and glycerylphosphorylethanolamine (GPE) respectively. GPC and GPE have been used in the field of food and pharmaceuticals industries because of their special physiological functions. So using PLB in oil degumming can further increase economic efficiency of enzymatic degumming. Phospholipases C (PLC) can remove the phosphoric acid from PC or PE, which can be hydrolyzed into diacylglycerol (DAG) and become a part of neutral oil. So utilization of PLC in the enzymatic degumming can not only decrease the phosphorus content of the oil, but also increase the yield of refined oil. The optimizations of enzymatic degumming process have been focused on some basic parameters (degumming temperature, enzyme dosage, pH value and added water amount, etc.) as well as acid pretreatment and dispersion of the buffered water and enzyme in the oil. Enzymatic degumming process has been developed from single enzyme degumming process to composite enzyme process, and also from application of free enzymes to immobilized enzymes. The degumming process of combination of PLA (phospholipases A) and PLC can reduce the phosphorus of degumming oil, which is satisfying the demand of physical refining as well as maximizing the oil yield. Using the immobilized phospholipase in the degumming process can make enzyme recycling and reduce the cost of refining. This paper described kinds of phospholipases used in vegetable oil degumming processes and summarized current status of design and application of enzymatic degumming processes. In order to obtain a most economical degumming process with the lowest consumption, the appropriate phospholipases and enzymatic degumming process should be chosen according to the degumming effect, the value of by-product of modified phospholipids by phospholipases and the quality of crude oil. The available phospholipases have bad catalytic performance, which has become a bottleneck to impeding large-scale application of enzymatic degumming process. The techniques of enzyme modification can improve the activity and enhance thermo-tolerance or acid resistance of the phospholipases, and finally the degumming time can be reduced and the reaction temperature will be increased. Therefore, to obtain phospholipases with excellent performance and then design more energy-efficiently, more environmentally friendly enzymatic degumming processes will be principal research objectives in future.