A rice mutant with a giant embryo has increased levels of lipophilic antioxidants, E vitamers, and γ-oryzanol fraction

Background and objective Lipophilic compounds in rice bran have health beneficial and functional properties. These lipophilic antioxidants in a giant embryo mutant (GEDrew) derived from a tropical japonica variety Drew were determined to evaluate its potential as a specialty variety. Findings GEDrew had double the size of embryo and lower kernel weight than Drew. The majority of the tocols in the embryo were in the form of tocopherols with alpha-tocopherol accounting for approximately 70%, while the tocopherols in bran ranged from 22% to 43% of total tocols. On a per embryo basis, GEDrew had a higher quantity of tocols compared with Drew; however, on a weight basis, the concentration of tocols in GEDrew was less than Drew. The gamma-oryzanol concentration in embryos was the same for both the mutant and wild type. The smaller brown rice kernel size and bigger embryo size of GEDrew resulted in higher proportion of bran + embryo (w/w), which led to higher total tocopherols, tocotrienols, and gamma-oryzanol in the whole grain of GEDrew relative to Drew. Conclusion A rice mutant with a large embryo had an elevated level of gamma-oryzanol and tocols, both as a group and as individual homologs, in whole grains as compared to the wild type. Significance and novelty GEDrew has the potential to be grown as a specialty rice variety for the purposes of isolating its bran, oil, and lipophilic antioxidants for use by the food and cosmetic industries.