Comparative Studies on Volatile Components of Non-Fragrant and Fragrant Rices

Volatile compounds (70 in all) were identified in cooked fragrant and non-fragrant rice. The most important compounds were alkanals, alk-2-enals, alka-2,4-dienals, 2-pentylfuran, 2-acetyl-1-pyrroline and 2-phenylethanol, but many other compounds were identified that contributed to the total aroma profile. Non-fragrant rice (Pelde) contained much more n-hexanal, (E)-2-heptenal, 1-octen-3-ol, n-nonanal, (E)-2-octenal, (E)-2,(E)-4-decadienal, 2-pentylfuran, 4-vinylguaiacol and 4-vinylphenol, than the fragrant rices (Basmati, Jasmine, Goolarah, YRF9). Jasmine and Goolarah had much more indole, Goolarah and YRF9 had higher amounts of 2-acetyl-1-pyrroline compared with those of Pelde, whilst Basmati had the highest amount of 2-phenylethanol and the lowest content of n-hexanal among all the rice types examined. Results of the sensory evaluation showed that YRF9 and Goolarah had the highest pandan-like aroma whilst Basmati had the highest popcorn-like aroma.