Polyunsaturated fatty acids (PUFAs), especially omega-3 fatty acids, are an area of much interest and extensive scientific research in recent years. There are numerous articles available in various scientific publications about the presence and value of PUFAs present in food and food products. Due to their relatively non-polar nature, these compounds are good candidates for extraction with supercritical CO2.
There is an abundance of new information regarding the biological effects and health implications of this type of fatty acid [1]. Nutrition experts have recently recommended an increase in PUFA consumption to maintain an omega-6/omega-3 ratio of 5:1 and 10:1 in the diet.
Professor Sagrario Beltrán and his colleagues at the Department of Biotechnology and Food Science at the University of Burgos in Burgos, Spain worked to optimize the supercritical fluid extraction of the omega-3 fatty acids of oil from hake by-products [2]. Their research determined the optimal extraction conditions to maximize the extraction rate were 25MPa, 40◦C and a flow rate of 10 kg CO2/hr. (13.75 kg CO2/h). Under these conditions, the extraction yield obtained after a 3-hour run was 96.4%.
An interesting observation that typically holds true for solid matrix/natural product extraction processes in a sc-CO2, is that the supercritical extraction from solids is often controlled by the particle size of the matrix material that best exposes the maximum surface area to the sc-CO2 and allows easy transport of the analyte of interest out of the solid phase and into the liquid phase for extraction. It is important to consider that very small particles may hinder the fluid flow of sc-CO2 through the particles bed and decrease external analyte mass transfer. It is found for most natural products extraction that 200-micron particle size with a moisture content below 8% offers the optimized region for efficient extraction.
Supercritical Fluid Technologies, Inc. specializes in SFE equipment for these kinds of applications, supplying extractors such as the SFT-120 for small scale optimization as well as larger benchtop and pilot scale systems like the SFT-150, SFT-250 and the SP series SFEs, optimized for the extraction of a wide variety of natural products.
To learn more about this versatile sc-CO2 extractor, please see: https://www.supercriticalfluids.com/products/supercritical-fluid-extraction-products/
[1] C.K. Chow (Ed.), Fatty Acids in Foods and Their Health Implications, Marcel
Dekker, Inc., New York/Basel, 2000.
[2] WHO/FAO, Fats and oils in human nutrition, in: FAO (Ed.), 1994.