Characterization of volatile aroma compounds in cooked black rice.
Black rice ( Oryza sativa L.), an aromatic specialty rice popular in Asia, has a unique flavor, the volatile chemistry of which has not been reported. The objectives of this research were to study volatile profiles of cooked black rice and to characterize the odor-active compounds. Thirty-five volatile compounds were identified by gas chromatography-mass spectrometry using a dynamic headspace system with Tenax trapping. Aldehydes and aromatics were quantitatively in the greatest abundance, accounting for 80.1% of total relative concentration of volatiles. The concentration of 2-acetyl-1-pyrroline (2-AP) was high, exceeded only by hexanal, nonanal, and 2-pentylfuran. A total of 25 odor-active compounds, determined by gas chromatography-olfactometry, were applied to principal component analysis, demonstrating significant differences between a black and a traditional white rice cultivar in terms of aroma and explaining 93.0% of the total variation. 2-AP, guaiacol, indole, and p-xylene largely influenced the difference between the aroma in cooked black and white rice. 2-AP and guaiacol were major contributors to the unique character of black rice based on odor thresholds, relative concentrations, and olfactometry.
Yang
Dong Sik
DS
University of Georgia, Plant Sciences Bldg, Athens, GA 30602-7273, USA.
Lee
Kyu-Seong
KS
Jeong
O-Young
OY
Kim
Kee-Jong
KJ
Kays
Stanley J
SJ
D002849:Chromatography, Gas; D008401:Gas Chromatography-Mass Spectrometry; D006139:Guaiacol / Q000032:analysis; D006358:Hot Temperature; D006801:Humans; D009812:Odorants / Q000032:analysis*; D012275:Oryza / Q000737:chemistry*; D011758:Pyrroles / Q000032:analysis; D012639:Seeds / Q000737:chemistry; D012903:Smell; D014835:Volatilization
D011758:Pyrroles; D006139:Guaiacol; C426303:2-acetyl-1-pyrroline