Characterization of biotransformation, transmission and elimination processes in humans: Influence on the odorant and metabolite profiles of breath, urine and human milk

越来越多的研究报告说，生物转化过程可能导致有气味的物质发生实质性改变，但也可能导致与食物一起摄入的无味挥发性物质发生实质性改变。此外，由于生理过程，从无气味的前体新形成的气味剂已在文献中描述。为了描述这些过程，在人乳中监测大蒜的感官相关物质及其潜在代谢物，也在人类受试者的尿液和呼出的气体中监测。在我们之前的项目Bu 1351/15-1中，我们全面调查了涉及生大蒜干预的食品相关情况，从而将干预的数据与相应的对照实验进行了比较。食用生大蒜前后的母乳感官评价表明，食用大蒜后约2.5 h的牛奶气味发生了变化，并且可以检测到大蒜/卷心菜样气味。采用气相色谱-质谱/嗅觉法（GC-MS/O），在食用生大蒜后的母乳和尿液中检测到大蒜衍生的3种代谢物，即烯丙基甲基硫醚（AMS）、烯丙基甲基亚砜（AMSO）和烯丙基甲基砜（AMSO2）。然而，AMS是唯一的气味活性代谢物，散发出明显的大蒜味；另外两种代谢物即使在高浓度下也没有气味。这三种代谢物进入特定体液的排泄率被发现具有强烈的时间依赖性，并且在个体测试者之间以及不同测试日的个体之间存在差异。同时，我们应用质子转移反应-质谱（PTR-MS）结合呼吸端潮汐采样系统，对受试者的肺泡空气进行与大蒜摄入有关的采样。分析显示，在食用大蒜的受试者呼出的气体中出现了AMS和甲硫醇，但不同个体的排泄率也有很大差异。这些发现表明，一方面，生大蒜的挥发性气味部分被强烈代谢，但另一方面，大蒜衍生的代谢物通过不同的体液有相似的排泄途径。基于这些前提，现在建议在实际条件下监测烤和煮大蒜摄入的生物转化和传播以及消除过程；因此，大蒜气味和代谢物将再次进行定性和定量监测，但也是在时间解决的基础上。这种方法将使我们能够阐明潜在的时间动力学，再次比较母乳，尿液和呼吸的生理介质，并将从新鲜大蒜中获得的知识转化为与加工大蒜相关的效果。

An increasing number of studies report biotransformation processes that may lead to substantial modification of odorants but also odorless volatile substances that are ingested with food. Also, neo-formation of odorants from non-odorous precursors due to physiological processes has been described in the literature. To characterize these processes, sensorially relevant substances of garlic, together with their potential metabolites, are monitored in human milk, but also in urine and exhaled breath of human subjects. In our previous project Bu 1351/15-1 we comprehensively investigated a food-relevant situation involving intervention with raw garlic, thereby comparing data from the intervention with the respective control experiments.The sensory evaluation of the human milk taken before and after the consumption of raw garlic showed that the odor of milk taken about 2.5 h after garlic consumption was altered, and that a garlic/cabbage-like odor was detectable. Using gas chromatography-mass spectrometry/olfactometry (GC-MS/O), three garlic-derived metabolites, namely allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO) and allyl methyl sulfone (AMSO2), could be identified in breast milk and urine samples after raw garlic intake. However, AMS was the only odor active metabolite emitting a clear garlic-like smell; the two other metabolites were odorless even at high concentrations. The excretion rates of the three metabolites into the specific bodily fluids were found to be strongly time-dependent and differed between the individual test persons as well as for one individual at different test days. In parallel we applied proton transfer reaction-mass spectrometry (PTR-MS) coupled with a breath end tidal sampling system for the sampling of alveolar air of test persons in relation to garlic intake. The analysis revealed the appearance of AMS and methanethiol in the exhaled breath of test persons consuming garlic, but again with very different excretion rates for different individuals. These findings demonstrate that, on the one hand side, the volatile odorant fraction of raw garlic is strongly metabolized, but, on the other side, that there are similar excretion pathways for garlic-derived metabolites via different bodily fluids.Based on these premises, biotransformation and transmission, as well as elimination processes are now proposed to be monitored under real-life conditions for roasted and cooked garlic ingestion; thereby, garlic odorants and metabolites will again be monitored qualitatively and quantitatively, but also on a time-resolved basis. This approach will enable us to elucidate the underlying temporal kinetics, again comparing the physiological media breast milk, urine and breath, and to translate the knowledge gained with fresh garlic into effects that are related to processed garlic.