Effects of roasting on physicochemical characteristics and flavor substances of germinated brown rice

Roasting can dissolve the nutrients accumulated in germinated brown rice (GBR). This study investigated the effects of roasting on physical properties, nutrients and flavor substances of GBR. Results demonstrated that longer roasting time resulted in more browning and a decrease in the moisture content. The total soluble sugar content increased significantly, while the soluble protein content decreased initially and then slightly increased. Roasting also resulted in a decrease in γ-aminobutyric acid (GABA) content. However, the content of total phenolics increased significantly. Phenolic acids content increased and then decreased with the roasting time. The volatile components of GBR were found to be mainly organic sulfides and furans after roasting, 1-pentene-3-alcohol and 2-butanone (dimer) were the most differentiating components contributing to the distinguish of roasting times. Correlation analysis showed that total soluble sugar and GABA were important flavor precursors. These findings provide a theoretical basis for development of GBR-based products.