Yang Dong Sik, Shewfelt Robert L, Lee Kyu-Seong, Kays Stanley J
Department of Horticulture, The University of Georgia, Athens, Georgia 30602-7273, USA.
J Agric Food Chem. 2008 Apr 23;56(8):2780-7. doi: 10.1021/jf072685t. Epub 2008 Mar 26.
Using a dynamic headspace system with Tenax trap, GC-MS, GC-olfactometry (GC-O), and multivariate analysis, the aroma chemistry of six distinctly different rice flavor types (basmati, jasmine, two Korean japonica cultivars, black rice, and a nonaromatic rice) was analyzed. A total of 36 odorants from cooked samples were characterized by trained assessors. Twenty-five odorants had an intermediate or greater intensity (odor intensity >or= 3) and were considered to be major odor-active compounds. Their odor thresholds in air were determined using GC-O. 2-Acetyl-1-pyrroline (2-AP) had the lowest odor threshold (0.02 ng/L) followed by 11 aldehydes (ranging from 0.09 to 3.1 ng/L), guaiacol (1.5 ng/L), and 1-octen-3-ol (2.7 ng/L). On the basis of odor thresholds and odor activity values (OAVs), the importance of each major odor-active compound was assessed. OAVs for 2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, and nonanal comprised >97% of the relative proportion of OAVs from each rice flavor type, even though the relative proportion varied among samples. Thirteen odor-active compounds [2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, nonanal, 1-octen-3-ol, ( E)-2-octenal, ( E, E)-2,4-nonadienal, 2-heptanone, ( E, E)-2,4-decadienal, decanal, and guaiacol] among the six flavor types were the primary compounds explaining the differences in aroma. Multivariate analysis demonstrated that the individual rice flavor types could be separated and characterized using these compounds, which may be of potential use in rice-breeding programs focusing on flavor.
使用带有Tenax捕集阱的动态顶空系统、气相色谱-质谱联用仪（GC-MS）、气相色谱-嗅觉测量法（GC-O）以及多变量分析，对六种截然不同的大米风味类型（印度香米、茉莉香米、两个韩国粳稻品种、黑米和一种非香米）的香气化学进行了分析。经过训练的评估人员对煮熟样品中的36种气味物质进行了表征。25种气味物质具有中等强度或更高强度（气味强度≥3），被认为是主要的气味活性化合物。使用GC-O测定了它们在空气中的气味阈值。2-乙酰基-1-吡咯啉（2-AP）的气味阈值最低（0.02 ng/L），其次是11种醛类（范围从0.09至3.1 ng/L）、愈创木酚（1.5 ng/L）和1-辛烯-3-醇（2.7 ng/L）。基于气味阈值和气味活性值（OAVs），评估了每种主要气味活性化合物的重要性。尽管不同样品之间相对比例有所不同，但2-AP、己醛、（E）-2-壬烯醛、辛醛、庚醛和壬醛的OAVs占每种大米风味类型OAVs相对比例的>97%。六种风味类型中的13种气味活性化合物[2-AP、己醛、（E）-2-壬烯醛、辛醛、庚醛、壬醛、1-辛烯-3-醇、（E）-2-辛烯醛、（E，E）-2，4-壬二烯醛、2-庚酮、（E，E）-2，4-癸二烯醛、癸醛和愈创木酚]是解释香气差异的主要化合物。多变量分析表明，使用这些化合物可以分离和表征各个大米风味类型，这可能在专注于风味的水稻育种计划中具有潜在用途。
