Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 12/10/2011
Publication Date: 12/30/2011
Citation: Banuelos, G.S. 2011. Biological production of selenium-biofortified products from natural-occurring sources of selenium. In: Banuelos, G.S., Lin, Z.Q., Yin, X.B., editors. Selenium-global Perspectives of Impacts on Humans, Animals and the Environment. Hefei, China: University of Science and Technology of China Press. p. 77-79. Interpretive Summary: There are many human and animal health problems associated with low bioavailable selenium concentrations in edible food and feed products produced in many countries of the world. Biofortification is a suggested strategy that generally produces crops that are specifically enriched with the lacking micronutrient, e.g., selenium. Growing selected crops in soils that are naturally rich with selenium is being done in the westside soils of central California. USDA-ARS researchers have initiated a selenium biofortification program by utilizing a plant's ability to absorb selenium. In this regard, they have conducted multi-year studies with Brassica species, e.g.,broccoli, mustard, canola, and Prince’s Plume on selenium-contaminated soils. From canola and mustard, plant seed was harvested and oil was extracted for biofuel production. The resulting seed meal was enriched with selenium. The selenium hyper-accumulator plant-Prince’s Plume was harvested and ground into a selenium-rich plant-based fertilizer. In the second part of the studies, the organic fertilizer was added to soil growing broccoli, while the selenium-enriched seed meal was fed to chickens and to dairy cows as part of their daily feed ration. Results show that we were able to naturally produce selenium-enriched broccoli, chicken eggs, and milk from both organic sources of selenium. These new biofortified food products contain organic forms of selenium that are generally more bioavailable for human absorption, and could be of importance human consumption in selenium-deficient regions around the world.
Technical Abstract: Health problems associated with soil selenium (Se) deficiency and its subsequent low accumulation by plants have become major nutritional issues in many countries. Of the many strategies employed to increase animal and human absorption of Se, biofortification is a recent technique that utilizes a plants ability to accumulate and store various forms of bioavailable Se. In the westside soils of central California, natural-occurring Se exists from geological sources, e.g., the California Coast Ranges. Hence, multi-year studies were conducted on Se-laden soils (oxalis silty clay loam) in which soluble Se concentrations ranged from 0.1 to 1.4 mg/L to a depth of 60 cm. The following crops were evaluated; broccoli ( Brassica olecera), mustard (Synapis alba), canola (B. napus) and Prince’s Plume (Stanleya pinnata). At harvest, seed from canola and mustard were pressed for oil (i.e., biofuel), and residual seed meals were used for feeding both egg-laying chickens in a 5-week trial and Jersey dairy cows in a 2 month trial. S. pinnata was harvested, ground, and used as a Se additive for growing broccoli. In all plant parts, content was measured by ICP-MS, strong anion exchange HPLC-ICP-MS, micro-focused X-ray fluorescence elemental and chemical mapping, and the Se K-edge X-ray absorption near-edge structure analysis. Results showed Se increases in egg yolk and whites after 5-weeks of feeding chickens, and up to 25 % more Se in milk after 7 weeks. In addition, increases in Se were measured in broccoli florets harvested from soils amended with S. pinnata prior to planting. Our results clearly demonstrate that Se-enriched plant material originating from natural-occurring Se, can successfully be utilized for producing Se-biofortified edible products with different forms of more bioavailable Se. These new Se-enriched products may be useful in selenium-deficient regions around the world.