Isolation and identification of steroidal hydrocarbons in soybean oil deodorizer distillate

In the isolation of squalene from soybean oil deodorizer distillate (SODD), ca. 30% of nonpolar lipid fraction (NPLF) is hydrocarbons (HCs), which can be divided into three main groups, namely aliphatic HCs, steroidal HCs and terpene HCs. The steroidal HCs content of vegetable oil can be used as a means of identifying the oil and therefore, for detecting adulteration. The objective of this study was to isolate the steroidal HCs contained in SODD and identify the individual steroidal HCs. Isolation of steroidal HCs can be achieved in three steps: modified Soxhlet extraction, modified silica gel column chromatography, and distillation. Identification of individual steroidal HCs was accomplished by TLC, GC and GC-MS analyses. The GC chromatogram of steroidal HCs showed five major peaks. Most of the major peaks were identified as derivatives of free sterols. Special attention was needed in order to identify isomers which differ in the position of double bonds and compounds which have three double bonds in the ring system.