Changes of Tocopherols, Tocotrienols, γ-Oryzanol, and γ-Aminobutyric Acid Levels in the Germinated Brown Rice of Pigmented and Nonpigmented Cultivars

This study examined the changes of tocopherols (Toc), tocotrienols (T3), gamma-oryzanol (GO), and gamma-aminobutyric acid (GABA) contents in germinated brown rice (GBR) of pigmented and nonpigmented cultivars under different germination conditions. Results showed that the Toc and T3 contents in GBR were significantly different between treatments in both rice cultivars. The pigmented GBR possessed higher total vitamin E, total Toc, total T3, and GO contents than the nonpigmented GBR; however, its level of GABA was lower. The order of the three highest vitamin E homologues in pigmented and nonpigmented GBR was gamma-T3 > gamma-Toc > alpha-Toc and alpha-Toc > gamma-T3 > alpha-T3, respectively; beta-Toc, beta-T3, delta-Toc, and delta-T3 were present in only small amounts (<= 1.0 mg/kg) in GBR of both cultivars. Although both cultivars showed an increase in GABA contents with increasing germination time, the GABA content in nonpigmented GBR was higher.