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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #328472

Research Project: Genomic Approaches and Genetic Resources for Improving Rice Yield and Grain Quality

Location: Dale Bumpers National Rice Research Center

Title: Enhancing the health-beneficial qualities of whole grain rice

Author
item Chen, Ming-hsuan
item Min, Byungrok - University Of Maryland Eastern Shore (UMES)
item Bergman, Christine - University Of Nevada
item Mcclung, Anna
item Mcclung, Anna
item Pinson, Shannon
item Boue, Stephen

Submitted to: AACC International
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2016
Publication Date: 10/23/2016
Citation: Chen, M., Min, B., Bergman, C.J., Mcclung, A.M., Pinson, S.R., Boue, S.M. 2016. Enhancing the health-beneficial qualities of whole grain rice. AACC International. http://www.aaccnet.org/meetings/mtgpresentations/Pages/2016Abstracts.aspx?LID=282.

Interpretive Summary:

Technical Abstract: Various pre- and post-harvest approaches (i.e. pre-germination of whole grains and reduced milling degree) to enhancing the health beneficial compounds of whole grain and milled rice have been reported. A discussion of the results from our pre-harvest efforts is as follows. The majority of rice consumed today is in its milled form, which is the endosperm portion of the whole grain rice that is 90% of the whole grain by weight. It is primarily composed of starch and a small portion of protein. The evidence is increasing that the portion of starch that is resistant to hydrolysis in the small intestines has health benefits, such as lowered postprandial glucose levels, increased mineral uptake and is associated with a reduced risk of developing colon cancer. We evaluated a set of high amylose varieties for resistant starch levels. Varieties with higher resistant starch content, after cooking, compared to conventional US high amylose types were identified. These genotypes are suitable for use as parents in varietal improvement efforts. The consumption of whole grains is recommended by many health related agencies because this may reduce the risk of developing various chronic diseases. Whole grain rice, with the bran layer intact, provides more nutrients than milled rice, specifically dietary fiber, minerals, vitamins, essential fatty acids, and bioactive compounds, including lipophilic antioxidants (i.e., vitamin E family and gamma-oryzanol) and phenolics. The typical whole grain rice sold across much of the world is light brown in color. Recently, rice with darker colored bran has gained significant attention because of its higher levels of phenolic compounds including flavonoids, anthocyanins and proanthocyanidins. These phenolics have many proposed health beneficial properties in addition to their antioxidant and anti-inflammatory properties. We have studied a diverse set of genotypes with dark colored bran and determined that it is possible to develop rice with bran containing high levels of total phenolics, anthocyanins, proanthocyanidins along with proanthocyanindins that differ in degree of polymerization profiles. Significant genotypic variation in concentrations of vitamin E and gamma-oryzanol has also been found. We investigated the stability of these compounds to hydrothermal processes. Lipophilic antioxidants were stable after hydrothermal processes; while the anthocyanins and proanthocyanidins were less stable relative to those in un-cooked whole grain. Both the concentrations and proportion of oligomers and polymers of proanthocyanidins were altered after hydrothermal processing. In conclusion, high levels of and varying profiles of bioactive compounds in the bran and endosperm of rice were identified using genetically diverse genotypes. This provides opportunity to develop specialty rice varieties enriched with compounds proposed as having health-promoting properties.