Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/1996
Publication Date: N/A
Interpretive Summary: The extraction of oils from seed matrices is normally accomplished using chemical solvents, a process that introduces small quantities of these toxic solvents into the environment and resultant seed oil and meal. Extraction with high pressure carbon dioxide (CO2) can accomplish the same goal using a non toxic and environmentally-benign medium (CO2). This manuscript reports on the use of CO2 along with ethanol, to remove not only soybean oil from soybean flakes, but a valuable constituent left over in the soybean meal after extraction of the oil, which are called phospholipids (Pls). Phospholipids are of high value and find many uses as food additives, in cosmetics, and in drug delivery systems. The process described in this research first consists of removing the soybean oil with CO2, and then using mixtures of CO2 blended with ethanol to affect removal of the Pls from the deoiled meal. Most of the PL constituents remaining in the meal are removed at 70% levels or above with the CO2/ethanol solvent system. The advantages to the process besides the recovery of the soybean oil and constituent Pls, are the production of a soybean basic protein meal, free of any objectable solvents, that can be used as an animal or human food ingredient.
Technical Abstract: Phospholipid (PL) mixtures are traditionally obtained from a by-product associated with the seed oil processing industry. Supercritical carbon dioxide (SC-CO2) extraction of seed oils leaves much of the PL content of the seeds in the deoiled meal, whereas in the traditional refining process, the PLs are partially partitioned into the hexane-extracted oil. We have devised a two step, sequential scheme for the extraction of both oil and PL-containing fractions using SC-CO2 and SC-CO2/ ethanol mixtures. Experimental data indicate that the PLs are selectively removed from the flakes using SC-CO2/ethanol mixture. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are more readily solubilized in the SC-CO2/cosolvent mixtures than phosphatidylinositol and phosphatidic acid. The extent of recovery of PC and PE is a function of the molar fraction of cosolvent in the SC-CO2. Some selective fractionation of the constituent phospholipids can be achieved by varying the molar fraction of ethanol dissolved in the SC-CO2. The extracts from the SF process were characterized by inductively coupled plasma spectroscopy and high performance liquid chromatography/evaporative light scattering detection analysis, for total phosphorus and individual PL content, respectively.