Centre for Green Chemistry, School of Chemistry, Monash University, Wellington Rd, Clayton, Victoria 3800, Australia.
Food Chem. 2013 Dec 15;141(4):4324-32. doi: 10.1016/j.foodchem.2013.05.156. Epub 2013 Jun 11.
A systematic experimental procedure is used to identify the aroma-impact compounds, leading to a shelf quality index based on head space solid-phase microextraction. Dried (ground) fennel seeds, having shelf life of 6 months (0.5Y) and 5 years (5Y), were used as a spice model for assessment of comparative aroma quality. Aroma-impact odorants were analysed by GC-olfactometry (GC-O) in parallel with comprehensive two-dimensional GC-flame ionisation detection (GC×GC-FID) using a polar/non-polar phase combination for the GC×GC column set. Tentative identification of aroma-impact odorants involved correlating data from the GC-O/FID system with GC×GC-time-of-flight mass spectrometry analysis by means of retention indices. Major compounds responsible for aroma perception were limonene, 1,8-cineole, terpinen-4-ol, estragole and trans-anethole, and showed an average decrease of 30-50% NIF from 0.5Y to 5Y. Monoterpenes which represent 'freshness', e.g. β-pinene and β-myrcene, exhibited identifiable aroma-impact only for the 0.5Y product. Sesquiterpenes and sesquiterpene oxides are suggested as an aging index, being present in increased amounts in 5Y. p-Anisaldehyde odour intensity for both samples remained the same (aroma perception sweet creamy, floral odour and Chinese seasoning powder).
采用系统的实验程序来鉴定香气影响化合物，从而基于顶空固相微萃取建立货架质量指数。将具有 6 个月（0.5Y）和 5 年（5Y）货架寿命的干（磨碎）茴香种子用作香料模型，以评估比较香气质量。使用极性/非极性相组合的 GC×GC 柱对 GC-嗅觉（GC-O）和全二维 GC-火焰离子化检测（GC×GC-FID）平行分析香气影响的气味物质。通过保留指数，通过 GC-O/FID 系统与 GC×GC-飞行时间质谱分析的数据相关联，对香气影响的气味物质进行了初步鉴定。负责香气感知的主要化合物为柠檬烯、1,8-桉叶素、萜品-4-醇、茴香脑和反式茴香脑，从 0.5Y 到 5Y 的 NIF 平均降低了 30-50%。代表“新鲜度”的单萜烯，例如β-蒎烯和β-月桂烯，仅对 0.5Y 产品具有可识别的香气影响。倍半萜烯和倍半萜烯氧化物被认为是老化指数，在 5Y 中含量增加。两种样品的对甲氧基苯甲醛气味强度保持不变（香气感知为甜奶油、花香和中国调味粉）。
