46C-34 |
Effect of temperture and pressure on solvent properties of supercritical carbon dioxide |
C. W. SEO1, T. Culmer1, and L. C. Boyd2. (1) Food Science and Nutrition, North Carolina A&T State University, Human Environment and Family Science, 161 Carver Hall, Greensboro, NC 27411, (2) Food Science, North Carolina State University, Food Science, Raleigh, NC 27495 The use of carbon dioxide as a solvent in supercritical fluid extraction provides many advantages over other substances. Carbon dioxide is non-toxic, non-flammable, inexpensive, and easily removed from extracted products and is environmentally acceptable. Carbon dioxide also has selective solvent properties for non-polar lipids. The objective of this study is to analyze the fatty acid profile and amount of phospholipids in fat extracted from ground beef using supercritical carbon dioxide under different temperatures and pressures. Fats were extracted from freeze-dried beef using a commercial supercritical carbon dioxide extraction unit. Beef samples were dried with a laboratory freeze-dryer. Fat extraction temperatures were 400C and 500C. Fat extraction pressures were 34.5, 48.3 and 65.5 Mpa, respectively. The carbon dioxide flow rate was 5 L/min. The extracted fat was then methylated using borontriflouride and subjected for fatty acid profiling. Phospholipids were isolated from the extracted fat, and their composition was determined using a normal phase HPLC method. The amount of fat extracted increased significantly as the temperature and pressure increased in freeze-dried beef (p<0.05). At 400 C, with a pressure of 65.5 Mpa, 31% of fat was extracted. At 500C, under the same pressure, 34% of the fat was extracted. The fatty acid profile indicated that oleic acid was the major fatty acid, and palmitic acid was next most abundant. Five major acids were found, and their proportions in descending order were: oleic>palmitic>stearic>linoleic>linolenic. Even though the total amount of extracted fat was significantly different between 500C and 400C, the proportions of fatty acids were almost the same. Preliminary data also showed that there was no trend in phospholipid content in relation to temperature or pressure. This might indicate that neither a 10-degree temperature difference nor a 31 Mpa pressure difference alter the solvent characteristic of supercritical carbon dioxide.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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