Modern Methods of Degumming of Vegetable Oils: An Analytical Review

Abstract

The review article compares and discusses the most common ways to degumming vegetable oils. Its purpose is to update the information on this stage of vegetable oil refining in order to provide an opportunity to choose the optimal degumming method for the manufacturer. Degumming is the first of the stages of oil processing, designed to remove phospholipids, the presence of which makes it impossible to carry out high-quality performance of all subsequent stages of refining. The fractional composition of plant phospholipids of various oils is presented, the features of their structure, which affect their hydrophilicity, are considered. Various theoretical approaches to the degumming process are considered. The article compares the disadvantages, advantages and effectiveness of aqueous, acidic, enzymatic degumming, total degumming, and soft degumming. Enzymatic degumming is today considered the main method for extracting phospholipids from oils. Under industrial conditions, for oils with a low phospholipid content (for example, sunflower oil), the use of phospholipases in order to obtain a low-phosphoric oil (less than 10 ppm) is reasonable (with an eye to reducing oil losses at this stage). But this is only possible if preliminary acid degumming is carried out. The advantages and difficulties of enzymatic degumming are considered. The combination of acid degumming with alkaline neutralization is perhaps the most effective and easiest way to obtain oil with a low residual phospholipid content. Despite the traditional nature of this approach, it remains highly effective, the easiest to implement, and inexpensive. The intensification of the mixing of the phases "oil–degumming agent" leads to a significant increase in the efficiency of degumming. The article discusses the use of ultrasonic and cavitation devices for this purpose. A promising direction in the development of food industry technologies today is the use of membranes. The features of this physical method of degumming are considered. The selected type of degumming and the conditions for its implementation affect not only the composition and performance of oils, but also the quality and safety of a valuable by-product of this stage – lecithin. The highest quality lecithin is obtained as a result of water or enzymatic degumming – water or aqueous solutions of enzymes do not negatively affect the quality indicators of lecithin, its composition. Lecithin obtained by water degumming contains almost no non-hydrophilic phospholipids. Lecithin obtained using phospholipases contains increased amounts of lysoforms of phospholipids, which positively affects its surfactant properties.