酶法脱胶在植物油脂精炼中的应用进展

Application of enzymatic degumming on vegetable oils refining

酶法脱胶作为一种新型的植物油脂脱胶工艺,与传统脱胶工艺相比,具有脱胶完全、用水量和废水排放少、耗能低、精炼得率高等经济、环保的优点,因而备受各国油脂加工业的关注。随着酶法脱胶技术的发展,已有多种磷脂酶(A1、A2、B、C)应用于植物油脂脱胶;酶法脱胶工艺也从简单地优化基本参数(脱胶温度、酶添加量、p H值和加水量等)到结合优化酸预处理、水酶和油脂混合程度来提高脱胶效率,从单一酶脱胶工艺发展到复合酶脱胶工艺,由游离酶脱胶发展到固定化酶脱胶。该文介绍了植物油脂酶法脱胶工艺中使用的磷脂酶,综述分析了酶法脱胶工艺设计与应用现状及存在的问题。提出需综合考虑脱胶效果、磷脂改性副产品加工价值及植物毛油品质等因素,选择合适的磷脂酶和脱胶工艺才能使酶法脱胶同时达到低耗和经济的效果。目前制约酶法脱胶工艺大规模应用的一个重要因素是现有磷脂酶催化性能差,可通过酶人工改造技术提高磷脂酶活性和抗逆性从而解决目前酶法脱胶时间长,脱胶温度低等问题。因此开发性能优良的磷脂酶,并且相应地设计更节能、环保的脱胶工艺是未来植物油脂酶法脱胶研究的主要目标。

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.