Static headspace analysis of odorants in commercial rice proteins

Accurate identification of the odor-contributing compounds in aqueous slurries of rice proteins is necessary to improve their overall flavor characteristics. The objective of this study was to identify the primary odorants in rice protein slurries using static headspace analysis. Five commercial rice protein (RP) products, RP-G, RP-O, RP-RM, RP-RS1, and RP-RS2, were analyzed. RP-G contained the lowest levels of most of the odorants. Acetaldehyde was present in the highest amount in RP-O (0.434mg/m³). RP-RM had the highest levels of hexanal (5.907mg/m³), methanethiol (0.138mg/m³), pentanal (1.575mg/m³), and 2-pentylfuran (5.702mg/m³). Corresponding odor values were, 111, 86, 22 and 21, respectively. In RP-RS1 and RP-RS2, the predominant odorants were dimethyl disulfide, dimethyl trisulfide, and hexanal. The results showed the importance of the volatile compounds produced from amino acids, including the sulfur-containing compounds and acetaldehyde, as well as lipid oxidation derived odorants to the overall odor of rice proteins.