Research Group "Analytical Chemistry of Contaminants", Department of Chemistry and Physics, Research Centre for Mediterranean Intensive Agrosystems and Agrifood Biotechnology (CIAIMBITAL), Agrifood Campus of International Excellence (ceiA3), University of Almeria, E-04120 Almeria, Spain; Department for Sustainable Food Process - DiSTAS, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
Department for Sustainable Food Process - DiSTAS, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; Nutrition and Bromatology Group, Analytical and Food Chemistry Department, Faculty of Food Science and Technology, Univesidade de Vigo, Ourense Campus, 32004 Ourense, Spain.
Food Res Int. 2022 Dec;162(Pt B):112081. doi: 10.1016/j.foodres.2022.112081. Epub 2022 Oct 28.
Thyme is one of Europe's most consumed aromatic herbs and represents a matrix susceptible to intentional mislabelling and food frauds. In this study, a phenolic profiling approach based on UHPLC-QTOF-HRMS untargeted metabolomics was used to trace its geographical origin, as well as to assess the effect of post-harvest processing by comparing sterilized vs non-sterilized thyme. Both unsupervised and supervised statistics led to reliable sample clustering, high-quality model parameters, as well as the identification of a total of 45 differential compounds (markers) for discrimination purposes. The phenolic signature was markedly affected by environmental conditions related to the region of production, leading to an overall higher abundance of flavonoids in Moroccan thyme (from Fez), flavanols in Polish one (from Lublin), and tyrosols and other phenolics in thyme cultivated in Spain (from Castilla-La Mancha). The processing was also shown to play an important role in phenolic profiling, noticing not only the decrease of thermolabile phenolics (such as flavonoids) but also the enhancement of other phenolic subfamilies in response to sterilization. This study opens the path to novel metabolomics-based strategies to support the integrity of thyme and possibly other spices, scarcely studied so far.
百里香是欧洲消费最多的芳香草本植物之一，是一种容易被有意错误贴标签和食品欺诈的基质。在这项研究中，采用基于 UHPLC-QTOF-HRMS 无靶向代谢组学的酚类分析方法来追踪其地理来源，并通过比较灭菌和非灭菌百里香来评估其采后加工的影响。无监督和有监督的统计方法都导致了可靠的样本聚类、高质量的模型参数，以及总共鉴定出 45 种用于区分目的的差异化合物（标志物）。酚类特征明显受到与生产地区相关的环境条件的影响，导致摩洛哥百里香（来自非斯）中类黄酮的总含量较高，波兰百里香（来自卢布林）中黄烷醇的含量较高，而西班牙种植的百里香（来自卡斯蒂利亚-拉曼恰）中酪氨酸和其他酚类物质的含量较高。加工也被证明对酚类分析有重要影响，不仅注意到热敏性酚类物质（如类黄酮）的减少，而且还注意到其他酚类亚家族的增强，以应对灭菌。这项研究为基于代谢组学的策略开辟了道路，以支持百里香和其他迄今为止研究甚少的香料的完整性。
