Extraction and Enzymatic Modification of Functional Lipids from Soybean Oil Deodorizer Distillate

Crude vegetable oils contain triacylglycerols as major component and various minor components such as diacylglycerols, monoacylglycerols, free fatty acids, phospholipids, tocopherols, sterols, squalene, color pigments, waxes, aldehydes, ketones, triterpene alcohols and metals that may affect the quality of the final product. The minor components are removed partially or entirely by either physical or chemical refining in order to make the vegetable oils suitable for human consumption. Deodorization is the last major processing step in the refining of edible oils. It has the responsibility for removing both the undesirable ingredients occurring in natural fats and oils and those which may be imparted by prior unit processes such as caustic refining, bleaching, hydrogenation, or even storage conditions. It is this unit process that finally establishes the oil characteristics of "flavor and odor," which are those most readily recognized by the consumer (Gavin, 1978). Deodorizer distillate is a by-product of deodorization, which is the last major step in vegetable oil refining process. It is a complex mixture of free fatty acids, mono-, diand triacyglycerols, sterols and their esters, tocopherols, hydrocarbons, pesticides, and breakdown products of fatty acids, aldehydes, ketones and acylglycerol species (Ramamurthi & McCurdy, 1993). Deodorizer distillate is an excellent source of valuable compounds such as phytosterols, tocopherols and squalene, which can be recovered and further used as food additives, in pharmaceutical industry and cosmetics. Their commercial value however, is mainly dependent on their tocopherol content (Fernandes & Cabral, 2007). Although in recent years, efforts from industry resulted in a significant number of reports, describing better and improved methods for phytosterol recovery and purification. Such surge is closely related to growing market for phytosterols, particularly given the widespread dissemination of functional foods (Fernandes & Cabral, 2007). Numerous procedures have been described to isolate bioactive compounds from soybean oil deodorizer distillate to improve the value and the quality of this by-product. All these procedures can be grouped in three generic categories: crystallization and precipitation, chemical and enzymatic modification, and extraction and fractionation. One important bioactive compound concentrated in intermediate byproducts and waste streams during the refining of soybean oil is squalene. Recently, steroidal hydrocarbons and