Scott L. Taylor

Determination of oil content in oilseeds by analytical supercritical fluid extraction

The total oil content of soyflakes, canola seed and wetmilled corn germ were determined by analytical supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent. Results obtained by SFE were in excellent agreement with those obtained by a conventional Soxhlet technique with organic solvents. The analytical-scale SFE technique yielded average means within one standard deviation of the means derived from the organic solvent-based methodology. Matrices containing both high and low oil content were successfully extracted with carbon dioxide at comparable precision to that obtained with the standard procedure. The supercritical fluid-based technique appears to be a suitable replacement for traditional extraction methods with organic solvents, thereby potentially eliminating the costs associated with solvent disposal and exposure of laboratory personnel to toxic and flammable solvents.

Production of Tocopherol Concentrates by Supercritical Fluid Extraction and Chromatography

Abstract Supercritical fluid extraction (SFE) has been combined with supercritical fluid chromatography (SFC) in a preparative mode to develop a system for fractionating and enriching high value constituents contained in seed oil matrices. The system consists of an extraction step sequenced on-line with a sorbent filled column, which permits a SFE-enriched tocopherol fraction to be diverted onto the chromatographic column for further enrichment of the tocopherols. For the SFE stage, the tocopherol enrichment was optimized at 25 MPa and 80°C for soybean flakes and rice bran. However, total tocopherol recovery and enrichment was also found to be a critical function of the mass ratio of CO2/seed charge. Approximately 60% of the available tocopherols in soyflakes can be recovered in the SFE step, yielding enrichment factors of 1. 83–4.33 for the four tocopherol species found in soybean oil. Additional enrichment of tocopherol species can be realized in the SFC stage, ranging from 30.8 for delta-tocopherol to ...

Packed-bed bioreactor synthesis of feruloylated monoacyl- and diacylglycerols: clean production of a “green” sunscreen

A biocatalytic process for covalent incorporation of ferulic acid onto the glycerol backbone of vegetable oil proceeds efficiently, although rather slowly, with Candida antarctica lipase B in a packed-bed reactor. The bioreactor shows considerable long-term stability. Product yield is influenced by the water content of the fluid phase and enzyme support. The enzyme support modulates substrate concentrations through adsorption and subsequent release of reactants over the course of the reaction. The resulting product has excellent UVA/UVB absorbing properties, making it a potential substitute for conventional petroleum-based sunscreen active agents.

A comparison of oil and fat content in oilseeds and ground beef-using supercritical fluid extraction and related analytical techniques*

A supercritical fluid extraction (SFE) has been applied for the determination of total fat content of five different oilseed matrices (soybeans, sunflower, safflower, cottonseed and rapeseed) and ground beef samples containing approximately IO, 20 and 30% fat by weight. Lipid content was determined using both gravimetric analysis as well as the sum of all fatty acids, expressed as triglycerides, from the gas chromatography (GC) profiles of the fatty acid methyl esters (FAMES). The latter analysis is required by the Nutritional Labeling and Education Act of 1990 which redefined the determination of fat for nutritional labeling purposes. The oilseed results are compared to data from a collaborative study by the American Oil Chemists Society (AOCS) and the Association of Official Analytical Chemists International (AOAC). The collaborative study data were determined by both AOCS Official Methods and by SFE. All of our data yielded higher oil recoveries than the collaborative study data obtained via AOCS official methods and SFE with neat carbon dioxide (CO2). However, our results are in excellent agreement with the collaborative study data obtained by SFE with ethanol-modified CO? and the Federation of Oil, Seeds and Fats Association International method. The ground beef results are compared to previously published reports from our laboratory. They show that fat determination using GC-FAME analysis is equivalent to the gravimetric analysis results and has the additional benefit that different types of fat (i.e. saturated and monounsaturated) can also be determined in addition to total fat. Hence, the results from this study advocate the use of SFE as a suitable replacement for traditional organic solvent extraction in the determination of fat/oil content in agriculturally-derived products. Published by Elsevier Science Ltd

Analysis of tocopherols by capillary supercritical fluid chromatography and mass spectrometry

Tocopherol-containing mixtures were analyzed by gas chromatography (GC) and capillary supercritical fluid chromatography (SFC). GC analysis of tocopherols required the formation of the silyl derivatives, while SFC analysis of the tocopherol-containing mixtures was accomplished on neat samples. SFC analysis conditions were optimized with respect to column type and density/pressure programming. Enhanced resolution of many components was achieved by using inverse temperature programming during the SFC analyses. Both SFC and GC analyses permitted the separation and quantitation of alpha-, beta-, gamma- and delta-tocopherols. In addition, SFC proved particularly applicable for characterizing the composition of a deodorizer distillate and commercial antioxidant formulation. Coupling of a quadrapole mass spectrometer with a supercritical fluid chromatograph was also achieved; the mass spectrometer provided electron impact mass spectra on the underivatized tocopherol and sterol moieties. Both SFC and SFC/mass spectrometry proved effective for the analysis of complex lipid-containing mixtures, requiring minimal sample preparation prior to analysis.

Supercritical fluid extraction of Vernonia galamensis seeds

Abstract Vernonia galamensis is an excellent source of a seed oil rich in vernolic acid. However, the seeds of this plant exhibit a high lipase activity in the dormant state. The activity of this enzyme is apparent as vernonia oil will undergo lipolysis when the seeds are crushed prior to extraction. In this study, supercritical fluid extraction (SFE) utilizing carbon dioxide has been examined as an alternative solvent, at different pressures, temperatures and cosolvent concentrations. The use of supercritical fluid carbon dioxide (SC-CO2) as the extraction fluid under high temperatures and pressures has the potential to inhibit the lipolysis reaction during the extraction by reducing the activity of the enzyme, and hence the production of undesired fatty acids. Vernonia seeds were ground with dry ice prior to extraction to minimize any nascent lipase activity. Selective SFE was conducted at various pressures, temperatures, modifier concentrations, and total CO2 volume used to determine whether the vernolic acid content of the resultant extract could be enriched. An increase in pressure and temperature significantly increased the amount of extracted oil as well as the vernolic acid content. In addition, a significant reduction in the free fatty acid content of the oil from 69 to 8 mg/g oil was present with increasing extraction pressure. Exhaustive extraction of the oil could be attained via SFE with neat CO2 and with ethanol-modified CO2. However, regrinding the matrix after the initial extraction, followed by re-extraction of the seed matrix was necessary in these cases. The resultant oil and extracted meal were characterized with respect to free fatty acid, phospholipid, and percent protein contents.

Simultaneous multi-sample supercritical-fluid extraction of food products for lipids and pesticide residue analysis

Abstract Sample preparation for food analysis has traditionally involved the processing of a large number of samples simultaneously. A supercritical-fluid extraction (SFE) apparatus has been designed and tested to facilitate a similar approach, using SC-C02 as the extraction fluid. The prototype extractor was constructed to allow the extraction of six samples simultaneously, as well as the regulation and balancing of the fluid flow through each of the individual extraction vessels. In addition, procedures were developed to eliminate contamination from the apparatus and the extraction fluid which could interfere with electron capture detection of pesticide residues in meat samples. Rapid extraction of lipid phases from food products (soybeans, frankfurters, poultry) could be achieved within 15 minutes using extraction pressures of 5,000–10,000 psi at 60 °C and accompanying CO2 flow rates of 5–10 L min-1 (ambient conditions). Simultaneous multi-extraction of dispersed fat and soybean flake samples yielded lipid recoveries of 98 and 95%, respectively. Initial experiments on spiked frankfurter samples yielded analyte recoveries of 87–118% for a mixture of eight chlorinated pesticides. Additional studies on the coextraction of incurred organo-chlorine pesticide residues from poultry adipose tissue, resulted in 96% or better recoveries of endrin, heptachlor epoxide, and dieldrin, at the 1–3 ppm level in the extracted fat.