Processes to Recovery Profitable Products from Water Degumming Sludge of Vegetable Oils

Abstract

Oilseed world production in 2007/2008 was 391.2 Mt with a contribution of 56.4 % for soybean and 7.0 % for sunflower, according to United States Department of Agriculture (USDA) data. During the same period, 128.0 Mt of oils from seeds were produced along the world, including 29.3 % of soybean oil and 7.8 % of sunflower oil. During processing, some millions of tons of sludge or gums are generated in water degumming step, to remove impurities and obtain oils without turbidity and stable with respect flavor and odor. Degumming sludge is a complex mixture comprising high water content, phospholipids (PLs), oil, and minor amounts of other constituents like phytoglycolipids, phytosterols, tocopherols, and fatty acids. PL fraction in degumming sludge principally includes phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidic acid (PA). In this chapter, some traditional industrial processes to produce, purify, and fractionate lecithin, from degumming sludge are presented. These processes include drying and deoiling with acetone, a solvent in which PLs, glycolipids and related compounds are almost insoluble. Lecithin is used as emulsifiers, dispersing and release agent in food, pharmaceutical and cosmetic industries. Methods still not applied at industrial scale for extraction and partition of PLs using supercritical fluids, and processes for chemical and enzymatic modifications of lecithin are also reviewed in this chapter, with their advantages and disadvantages. Enriched lecithin in any component such us PC or PI, with distinctive surface-active properties can be obtained by lecithin fractionation with solvents. Special attention is dedicated in this review to novel structured PLs that can be obtained by enzymatic reactions to exchange fatty acids in natural PLs. These PLs are high-priced fine chemicals for membrane and lipoprotein investigation, cosmetic industries, and liposome technology to release food and medicament components. The extensive availability of different lipases and phospholipases, fatty acids and derivatives, including polyunsaturated fatty acids, to modify natural PLs and generate products with new physical and chemical properties, open a large investigation field at immediate future. Results of recent own investigation about recovery occluded oil in soybean degumming sludge, by water elimination and acetone extraction, and study on quality and stability indexes in recovered oils, in view to their re-insertion in productive process, are also shown in this review.