Location: Bio-oils ResearchTitle: Method for obtaining three products with different properties from fennel (Foeniculum vulgare) seed Author
Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2014
Publication Date: 6/17/2014
Publication URL: http://handle.nal.usda.gov/10113/60378
Citation: Moser, B.R., Zheljazkov, V.D., Bakota, E.L., Evangelista, R.L., Gawde, A., Cantrell, C.L., Winkler-Moser, J.K., Hristov, A.N., Astatkie, T., Jeliazkova, E. 2014. Method for obtaining three products with different properties from fennel (Foeniculum vulgare) seed. Industrial Crops and Products. 60:335-342. Interpretive Summary: This research revealed that several bio-based products can be obtained from fennel (Foeniculum vulgare) seeds. Those products include high quality animal feed as well as lipids and essential oils which can be used for numerous industrial, cosmetic, perfumery, nutraceutical, and pharmaceutical applications. Fennel was of interest because it is a hardy, perennial herb that is adapted to semi-arid climates such as those of the American west and it produces seeds which contain both lipid and essential oil components. One of the objectives of this study was to isolate the lipid, essential oil, and animal feed components from fennel seeds using sequential steam distillation and solvent extraction. Another objective was to characterize the composition and properties of each of these components for their applicability in various commercial applications. The results indicated that the lipid fraction contained a high percentage of monounsaturated fatty acids, especially petroselenic acid, which are desirable for derivatization into industrial products such as soaps, monomers, lubricants, detergents, and surfactants. The essential oil fraction exhibited excellent antioxidant activity and aroma, which are useful for cosmetic, perfumery, and biological applications. The residual seed meal remaining after essential oil and lipid extraction contained enough soluble protein to render it attractive as an animal feed supplement. These results will be important to chemical companies dedicated to incorporating bio-based products in their product portfolios, agricultural companies, farmers and ranchers interested in expanding markets for agricultural products, and consumers interested in products containing natural ingredients. This research may ultimately improve rural economies and public perception of bio-based products as well as reduce our national dependence on materials produced from imported, nonrenewable petroleum.
Technical Abstract: The objectives of this study were to determine the effects of distillation time (DT; 15-1080 min) on yield, composition, and antioxidant capacity of fennel (Foeniculum vulgare) seed essential oil (EO) as well as on the yield, composition, and properties of lipids extracted from steam-distilled fennel seeds (15-600 min). Further objectives included determining the impact of DT (15-600 min) on composition and quality of fennel seed meal for animal feed applications. EO yield increased with increasing DT to a maximum of 1.375% at 1080 min. The principal constituent was estragole, comprising 82-91% of the overall content. Other species included limonene, fenchone, and anethole. Antioxidant capacity of the EO was essentially unaffected by DT, with capacities ranging from 11.2-20.6 umol Trolox/g. The yield of lipids extracted from steam-distilled fennel seeds was unaffected by DT and ranged from 21.7-22.8 mass %. The fatty acid composition was also unaffected by DT, and the major constituents were petroselenic (67.0-71.3%) and oleic (12.0-16.4%) acids. The concentrations of tocopherols, tocotrienols, and phytosterols were unaffected by DT whereas unsaponifiables and EO content in lipids decreased with increasing DT. Acid value, kinematic viscosity, peroxide value, and pour point increased with increasing DT, whereas density decreased. Induction period, heteroatom content, and Gardner color were unaffected by DT. As DT increased, the contents of soluble protein, potassium, and sodium in fennel seed meal decreased whereas indigestible fibers increased. As a result, in vitro degradability of defatted, steam-distilled fennel seeds decreased with increasing DT. In summary, longer DT negatively impacted feed quality of steam-distilled, defatted seed meal and lipid quality but did not significantly affect EO composition and antioxidant capacity.