Location: Commodity Utilization Research2013 Annual Report
1a. Objectives (from AD-416):
The principal goal of the project is to improve the postharvest utilization of cottonseed thereby increasing value of U.S. cotton crop. This will be achieved by developing an improved understanding of cottonseed’s oil, protein, and gossypol components. The objectives of the project are: (1) To survey available accessions from the Genetic Resources Information Network (GRIN) cotton database for genotypes modified fatty acid profiles. (2) To prepare a series of gossypol derivatives and study their bioactivity. (3) To develop improved chromatographic methods for measuring low levels of gossypol. (4) To study the potential use of cottonseed protein in adhesive formulations. (5) Ro modify cottonseed oil hydrogenation processes to reduce levels of trans fatty acids. (6) Use model plant systems to identify and refine transgenic expression conditions for critical industrial oil biosynthetic genes. (7) Identify substrate specificity-determining sequences in pertinent genes from tung tree related species. (8) Tansfer knowledge of minimal necessary gene sets from current research (on tung tree genes) to other novel oilseed whose oil represents greater market size or strategic value; i.e., epoxy (from Crepis, Vernonia, and Euphorbia species) or acetylenic fatty acids (also from Crepis).
1b. Approach (from AD-416):
A number of analytical, chemical, microbial, and cell culture techniques will be employed to achieve the project goals. For fatty acid analysis, gas chromatography coupled with chemical derivatization will be used to profile the fatty acids from extracted cottonseed oil and hydrogenated oil samples. Laboratory synthesis methods will be used to generate gossypol derivatives and liquid chromatography methods will be used to separate and purify the resulting compounds. Microbial and cell culture assays will be used to study the bioactivity of the new compounds. Protein isolation methods will be used to recover cottonseed protein as concentrates and isolates, and these preparations will be used to formulate adhesive systems. Hot-plate pressing of plywood squares will be used to make samples to test for protein adhesive strength and durability. Modification of proteins will be achieved by chemical and physical methods.
3. Progress Report:
On project Objective 1, work on the effort to survey the cotton germplasm collection for seed oil fatty acid profile was ended because of the loss of temporary employee associated with the effort. Four Gossypium barbadense accessions were identified with high oleic acid content and the most productive accession has been increased at the winter nursery to produce seed for oil isolation. On Objective 2, several additional gossypol Schiff’s base derivatives were synthesized. Single crystals of four of these compounds were prepared, and their structures have been determined by X-ray diffraction. However, a good candidate for a charge density study has not been found. This has been sought to help explain why our attempts to form stable secondary amines from the Schiff’s base derivatives have to date failed. We continue to make cottonseed protein isolate (>90% protein) from cottonseed meals for adhesive studies (Objective 4). In addition, isolates were prepared from both glanded and glandless cotton varieties and characterized for their compositional and functional properties. The glandless isolates were very high in protein, exhibited high solubility in acid conditions, and had foaming and emulsion stabilization properties that would be useful in food processing. Studies on the use of cottonseed and soy protein isolates as protein-based adhesives continued. Cottonseed protein isolate, either by itself or modified with sodium dodecylsulfate, was found have greater adhesive strength than soy isolate when used to glue maple veneer strips. Additionally, cottonseed meal was extracted with water and salt solutions to prepare protein concentrates (with about 70% protein) and these meal fractions were also found to exhibit adhesive properties comparable to the properties obtained with cottonseed isolates. In general, cottonseed protein adhesive were found to exhibit better resistance to water than similar soy protein-based adhesives. Hydrogenation of soybean and cottonseed oils (Objective 5) was studied at two elevated pressures with three commercial catalysts. Higher hydrogen pressures produced lower levels of trans-fatty acids. The platinum catalyst gave the least amount of trans-fatty acids, followed by the nickel and palladium catalysts. Partially hydrogenated cottonseed oil contained noticeably less trans-fat than did the partially hydrogenated soybean oil when the oils were hydrogenated to the same degree of unsaturation. The experimental results were modeled kinetically. Initial trials that included sonication during hydrogenation were not effective at reducing trans-oriented fatty acids, and research in this direction has been curtailed. The ginning of cotton produces 15–42% of foreign materials, called cotton gin trash, which includes cotton burrs, stems, leaf fragments, and dirt. With collaborators at the National Center for Crops Utilization Research, the mechanical properties of plastic composites formed with cotton gin burr and low density polyethylene were studied. The results suggested that burr can be used to lower the cost of some plastic formulations.
1. Use of cotton gin trash as filler in polymer formulations. Byproducts or waste materials from agricultural processing typically have little value and limited markets. Typically, cotton gin trash is burned for its combustion value or simply ploughed back into fields. ARS researchers at New Orleans, LA and Peoria, IL incorporated cotton gin into plastic formulations, and the properties of the composites were found to be suitable for some applications. By using these materials, the cost of the plastics can be reduced, the materials become more biodegradable, and a potential market is formed from these otherwise waste materials.
2. Reduced trans-fatty acids from partially hydrogenated cottonseed oils. Currently there is a concern among nutritionists that trans-fatty acids in hydrogenated edible oils may pose a health risk to consumers. Soybean and cottonseed oils are routinely hydrogenation for incorporation into semi-solid fat products. ARS researchers in New Orleans, LA, showed that cottonseed oil was found to have less trans-oriented unsaturated fat than similarly hydrogenated soybean oil. Thus, in some applications, hydrogenated cottonseed oil may a better material to use for the formulation of semi-solid fat products.
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