|Recently Accepted Publications (page 6) August 2021|
This addresses USDA-ARS Research Goal: Crop plants with enhanced nutritional quality
Weber, A.M., Baxter, B.A., McClung, A.M., Lamb, M.M., Becker-Dreps, S., Vilchez, S., Koita, O., Wieringa, F., Ryan, E.P. 2021. Arsenic speciation in rice bran: agronomic practices, postharvest fermentation, and human health risk assessment across the lifespan. Environmental Pollution. https://doi.org/10.1016/j.envpol.2021.117962 (goes outside USDA site)
Rice bran is rich in fatty acids, phytochemicals, B and E vitamins, and soluble and insoluble fibers that may have protective effects against colon cancer, enteric infections, and diseases. However, there have been concerns regarding the amount of arsenic (As) found in some rice products. The rice plant is able to thrive under saturated flooded field conditions - an environment that makes some soil compounds, like arsenic, more available for plant uptake. The inorganic form of As, considered more toxic to humans than other forms, is primarily localized in the outer bran layer of the grain. Thus, globally there are concerns about possible dietary exposure of As from rice bran consumption. This study aimed to assess the impact of global production sites, irrigation management, soil treatments with an As-based herbicide, organic versus conventional management systems, and bran fermentation treatments on As contents found in rice bran. Bran samples (53) were obtained from 10 rice producing countries and were analyzed for As content. Wide variation was found in inorganic As concentrations (619 to 17 ppm) depending on where the bran was produced. Agronomic practices and soil conditions were identified as major influencers for As accumulation in the grain. Water saving irrigation practices such as alternate wetting and drying allow for non-saturated conditions in the soil that may help reduce As accumulation in the grain. Rice bran sourced from organic production systems, which generally have higher soil organic matter, tended to have higher levels of As than conventionally produced sources, but this varied greatly among production sites. Post-harvest fermentation of bran had little effect on bran As contents. With the suite of health benefits associated with rice bran, it is imperative to better understand how various production and post-harvest processes can optimize health beneficial compounds while minimizing any non-desirable compounds.