Schuh Christian, Schieberle Peter
Deutsche Forschungsanstalt für Lebensmittelchemie, Lichtenbergstrasse 4, D-85748 Garching, Germany.
J Agric Food Chem. 2005 Nov 2;53(22):8699-705. doi: 10.1021/jf051601i.
To identify the compounds evoking the characteristic cereal-like, sweet aroma of oat flakes, an aroma extract dilution analysis (AEDA) was applied to a distillate prepared by solvent extraction/vacuum distillation from commercial oat flakes. Among the nine aroma-active compounds detected by gas chromatography-olfactometry and AEDA in the flavor dilution (FD) factor range of 4-1024, eight odorants, for example, (E)-beta-damascenone, (Z)-3-hexenal, and butanoic acid, showed only low FD factors. However, one odorant eliciting the typical cereal, sweet aroma of the flakes was detected with the highest FD factor of 1024. By mass spectrometry and nuclear magnetic resonance measurements followed by a synthesis, (E,E,Z)-2,4,6-nonatrienal, exhibiting an intense oat flake-like odor at the extremely low odor threshold of 0.0002 ng/L in air, was identified as the key odorant of the flakes. By means of a newly developed stable isotope dilution analysis using synthesized, carbon-13-labeled nonatrienal as the internal standard, a concentration of 13 mug of (E,E,Z)-2,4,6-nonatrienal per kilogram of the flakes was measured. Model studies suggested linolenic acid as the precursor of nonatrienal in oats.
为了鉴定引发燕麦片特有的类似谷物的甜香气味的化合物，对通过溶剂萃取/真空蒸馏从市售燕麦片中制备的馏出物进行了香气提取物稀释分析（AEDA）。在气相色谱-嗅觉分析和AEDA检测到的九种香气活性化合物中，在风味稀释（FD）因子范围为4-1024的情况下，八种气味物质，例如（E）-β-大马酮、（Z）-3-己烯醛和丁酸，仅显示出较低的FD因子。然而，检测到一种引发燕麦片典型谷物甜香气味的气味物质，其最高FD因子为1024。通过质谱和核磁共振测量，随后进行合成，鉴定出（E,E,Z）-2,4,6-壬三烯醛，其在空气中极低的气味阈值为0.0002 ng/L时表现出强烈的燕麦片样气味，是燕麦片的关键气味物质。通过使用合成的碳-13标记壬三烯醛作为内标物新开发的稳定同位素稀释分析方法，测得每千克燕麦片中（E,E,Z）-2,4,6-壬三烯醛的浓度为13μg。模型研究表明亚麻酸是燕麦中壬三烯醛的前体。
