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Title: Macro and microminerals of four Cuphea genotypes grown across the upper Midwest USA

item KIM, KI-IN - University Of Minnesota
item Gesch, Russell - Russ

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 1/4/2015
Publication URL:
Citation: Kim, K., Gesch, R.W. 2015. Macro and microminerals of four Cuphea genotypes grown across the upper Midwest USA. Industrial Crops and Products. 66:38-43.

Interpretive Summary: Cuphea is a new oilseed crop that is primarily being developed for the use of its seed oil in manufacturing industrial products such as biofuels, lubricants, and cosmetic products. The quality of cuphea seed oil and the efficiency of processing it for manufacturing industrial products may be greatly affected by the content of minerals, especially heavy metals like lead, iron, and copper, found its seed. Furthermore, the content of minerals in cuphea seed might be affected by the soil and climate environment where thy are grown. However, little is known about what macro- and micro-nutrients are found in cuphea seed or what their concentration is, which is important information for those interested in processing seeds for industrial purposes. This study was performed in 2007 to identify and characterize the contents of nutrients in seeds of four different varieties of cuphea that were grown at four separate locations including one in ND, MN, IA, and IL. The different sites allowed us to explore how different soil types and climate may affect the mineral content and concentration of the cuphea varieties studied. The type of mineral and its concentration varied with cuphea variety and across the different environments where they were grown. Generally, heavy metals were found in cuphea seed that could present problems with processing them for biofuels and cosmetics. However, two of the varieties studied, PSR23 and HC-10, which are presently being grown commercially, contained very low to non-existent quantities of the heavy metals measured. This result indicates that these cuphea varieties offer oil of high quality for processing to industrial products. It was also discovered that because of the content of certain minerals, cuphea seed meal (i.e., byproduct after extracting oil) may be able to serve as a good animal feed. Results of this research will benefit the specialty seed, cosmetic, and biofuels industries, as well as other researchers working on developing cuphea as a domestic source of renewable oil used for industrial chemical manufacturing.

Technical Abstract: Cuphea seed oil can be used for many purposes from motor oil and cosmetic components to jet fuel because its seeds are a rich source of medium-chain fatty acids (C8:0 to C14:0). Processing cuphea oil to biofuel and other bioproducts of high quality can depend on the heavy metal content of its seed. However, little is known about the macro- and micro mineral content of its seed. The objective of this study was to evaluate mineral content of cuphea, especially heavy metal content for processing the oil into biofuels/bioproducts and determine how this may differ across environments. Four cuphea genotypes were evaluated; two of which were semi-domesticated genotypes [PSR23 and HC-10 (Cuphea viscosissima Jacq. × C. lanceolata W.T. Aiton)] and two were wild species (Cuphea wrightii and C. viscosisima (VS-6-CPR-1). The study was conducted at four locations in North Dakota (ND), Minnesota (MN), Iowa (IA), and Illinois (IL). The soil was a Perella silty clay loam at Prosper, ND; a Barnes loam at Morris, MN; a Clarion loam at Ames, IA; and an Osco silt loam at Macomb, IL. PSR23 and HC-10 were direct-seeded in the field and the two wild species were transplanted. All cuphea seeds contained some heavy metals. Although P and K were equally fertilized at all sites, the concentrations of P and K in seeds of PSR23 and HC-10 tended to be lower at the MN site than IA and IL sites, while the lowest P concentration was observed at the MN site for VS-6 and C. wrightii. Among Ca, Mg, and Na in cuphea seeds, Na had the lowest concentration. The average concentrations for micro metals ranged from 40 to 53 mg kg-1 for Zn, from 11.9 to 14.1 mg kg-1 for Cu. These concentrations are low compared to those found in many livestock feeds. Lead and V were sporadically observed at a few locations. Cobalt (Co) was only detected for VS-6 at IA and C. wrightii at IA and MN, while Cd was only found for HC-10 at ND, PSR23 at IA, and C. wrightii at ND. These results suggest that the concentrations of macro and micro minerals in cuphea seeds varied by genotype and environment. This information will be useful for those industries interested in processing cuphea seed oil for manufacturing biofuels, cosmetics and other specialty chemicals.