Characterization of Volatile Compounds in Different Colored Rices before and after Cooking by Headspace-Gas Chromatography-Ion Mobility Spectrometry

The volatile components of three different colored rices were characterized by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). A total of 64 peaks were detected, and 44 volatile compounds were identified. White rice liberated a high concentration of 2-mhyl-2-propenal, 3-methylbutanal, heptanal monomer and four unknown components after cooking. Red rice liberated a high concentration of heptanal (monomer and dimer), pentanal, 2-butylfuran, amyl aldehyde, furan, (E)-2-heptenal (monomer and dimer), octanal (monomer and dimer), (E)-2-octenal, n-nonanal (monomer and dimer), isopentyl alcohol, decanal, ethyl acetate, 2,3-butanedione, 2-pentylfuran, and 10 unknown compounds. Black rice released a high concentration of 2-pentanone, 2-hexenal, 3-butenenitrile, 3-methyl-1-pentanol, 1-octene-3-one, furfuryl alcohol, 2-methyl-ethyl butyrate, benzaldehyde, phenylacetaldehyde, propanedioic acid, dietyl ester, and two unknown components. After cooking, the number of aroma compounds in the three colored rices increased. In conclusion, headspace-gas chromatography-ion migration spectrometry can well characterize the aroma of different colored rices before and after cooking, making it easier for consumers to choose rice.