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United States Department of Agriculture

Agricultural Research Service

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Research Project: CRITICAL FLUIDS FOR PROCESSING AGRIMATERIALS

Location: Functional Foods Research Unit

2007 Annual Report


1a.Objectives (from AD-416)
The primary goal of this project is to demonstrate the technical and commercial feasibility of using critical fluids and heterogeneous catalysts to extract and process agrimaterials into value-added products. The long-term objective of this project is to develop new chemical processes to produce high-value products from plant materials. Over the next three years, we will focus on the following objectives:

Objective 1: Develop methods for the conversion of agrimaterials to platform chemicals. There are two aspects to this objective: a) the oxidation of seed oils to platform chemicals such as diacids and hydroxyacids; and b) the design and development of better catalysts for regioselective transformations, including the selective addition of aromatics to the double bond of unsaturated fatty acids.

Objective 2: Develop commercially viable processes based on critical fluids to convert ligno-cellulosic materials to fermentable sugars as well as convert vegetable oils to high-value products. There are two sub-objectives to this objective: a) develop commercially viable processes based on critical fluids such as carbon dioxide (CO2), water and/or ethanol to pretreat ligno-cellulosic biomass prior to its conversion via enzymatic hydrolysis to fermentable sugars; and b) use CO2-based critical fluids to improve the commercial viability of processes for enzymatically converting vegetable oils to high-value products such as feruloylated monoacyl- and diacylglycerides. Critical fluid processes will be evaluated for enhancement of these conversions and integration with downstream recovery processes for these high-value products.

New objective for FY08: Fractionation and characterization of pyrolysis oil.


1b.Approach (from AD-416)
New polyoxometalate catalysts will be synthesized, characterized and used to oxidatively cleave double bonds in oleic and petroselinic acids to form platform chemicals. This research will also evaluate critical fluid processes for the conversion of vegetable oils to high-value products, and critical fluid pretreatments for converting ligno-cellulosic biomass to fermentable sugars.


3.Progress Report
Two new methods for producing spreads and shortenings that are low in trans fatty acids were developed. In the first, vegetable oils were hydrogenated beyond the point at which these reactions are usually stopped. This gives a product low in trans fatty acid content, which is then used as a basestock for blending with vegetable oil to give the desired product with trans fatty acid levels near zero grams per serving.

The second approach used a catalyst switching strategy to give basestocks of even lower trans fatty acid levels. In this method, soy, canola, high-oleic sunflower, and high-oleic safflower oils were hydrogenated to a specific point using a selective catalyst, then the catalyst was switched to a nonselective catalyst to further hydrogenate the product. This gave basestocks with trans fatty acid levels even lower than those using the first approach. Both of these strategies can be used with current industrial equipment and commercially available catalysts. Adoption of the second approach would not only give low trans fatty acid products, but could also increase the demand for crops grown on a limited number of acres. Expanded use of safflower oil should lead to expanded planting in areas where more profitable crops, such as corn and soybeans, do not perform as well.

Work on the catalytic conversion of vegetable oils has resulted in the preparation of new products from the oil isolated from Lesquerella and castor. Final characterization of these compounds and optimization of reaction conditions continue.

An apparatus for conducting carbon dioxide explosion experiments of ligno-cellusic materials has been constructed. Corn stover has been extracted with carbon dioxide in both a static as well as dynamic fashion using carbon dioxide. These materials will be subjected to hydrolysis and fermentation to determine differences in their subsequent ethanol yields.

A critical fluid fractionation column for purifying propyl esters from mono-, di-, and triglycerides was designed and built. This column was used to remove the esters without subjecting the mixture to heat and prevented acyl migration in the glycerides observed during vacuum distillation.


4.Accomplishments
Critical fluid fractionation of reaction mixtures. Chemical reactions generally result in a mixture of unreacted starting material and unwanted by-products in addition to the desired product. A fractionation column employing liquid carbon dioxide was designed and built to separate both unreacted starting material as well as by-products from a reaction mixture being used to study acyl migration in glycerides. The method developed removed essentially all of the by-products and did so without subjecting the product to the heat generally used during vacuum distillation and heat has been demonstrated to promote acyl migration in glycerides. This research provides technology which allows isolation of as pure products as well as the subsequent study of acyl migration in these separated materials. This same technology can be applied directly to the purification of SoyScreen™ as well. This effort directly supports National Program 306, Quality and Utilization of Agricultural Products, Action Plan Component 2-New Processes, New Uses and Value-Added Foods an Biobased Products, Problem Area 2c-New and Improved Processes and Feedstocks.


5.Significant Activities that Support Special Target Populations
None.


6.Technology Transfer

Number of active CRADAs and MTAs1
Number of non-peer reviewed presentations and proceedings2
Number of newspaper articles and other presentations for non-science audiences1

Review Publications
Eisenmenger, M., Dunford, N.T., Eller, F.J., Taylor, S.L., Martinez, J. 2006. Pilot scale supercritical carbon dioxide extraction and fractionation of wheat germ oil. Journal of the American Oil Chemists' Society. 10:863-868.

Stevenson, D.G., Eller, F.J., Jane, J., Inglett, G.E. 2007. Starch structures and physicochemical properties of a novel beta-glucan-enriched oat hydrocolloid product with and without supercritical carbon dioxide extraction. American Journal of Food Technology. 2(4):248-256.

Stevenson, D.G., Eller, F.J., Wang, L., Jane, J., Wang, L., Inglett, G.E. 2007. Oil and tocopherol content and composition of pumpkin seed oil in twelve cultivars. Journal of Agricultural and Food Chemistry. 55(10):4005-4013.

Stevenson, D.G., Eller, F.J., Radosavljevic, M., Jane, J., Inglett, G.E. 2007. Characterization of oat products with and without supercritical carbon dioxide extraction. International Journal of Food Science and Technology. 42:1489-1496.

Peterson, S.C., Eller, F.J., Fanta, G.F., Felker, F.C., Shogren, R.L. 2007. Effects of critical fluid lipid extraction on the gelatinization and retrogradation of normal dent cornstarch. Carbohydrate Polymers. 67(3):390-397.

Last Modified: 8/27/2014
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