MCCGC-IMS气相离子迁移谱用于Arabica、Robusta混合咖啡风味识别

Introduction
EU consumption of coffee in the year 2019 was about 45 million bags (one bag = 60kg) 2019年欧盟咖啡消费量约为4500万袋（一袋=60公斤）
Coffee market revenue (in million U.S. dollars) [2]:
(1) Germany 22457.52; (2) France 13198.85; (3) Italy 11831.6; (4) Spain 11635.26;
(5) Austria 4268.42.

Nowadays so-called “third wave” of coffee culture is observed.
Coffee is transformed from a regular commodity to a valuable handicraft product

如今，咖啡文化出现了所谓的“第三次浪潮”。咖啡从一种普通商品变成了一种有价值的手工艺品

There are two main groups of factors that can imply on coffee consumption and purchase:[3] 影响咖啡消费和购买的主要因素有两类：[3]

“sensory qualities”

•smell;气味
• taste;口感
are caused by:
• aroma of volatile organic compounds;挥发性有机物香气
• substances that are extracted with boiling water.用沸水提取物质

“functional motives”

• positive emotions; 积极情绪
• feeling of being aroused; 被唤起感官
• focused mental state; 集中精神状态
are caused by:
• caffeine (quantity and bioavailability) 咖啡因（数量和生物利用度）

Dependence between composition and quality
Despite habit changes, general consumer behavior remains the same: the most important demand is to get a high-quality product.
Fraud in coffee mixes is a widespread problem. In the most often case Arabica is replaced with more cheap Robusta species.
Due to the huge difference in compounds, a poor mix affects beverage quality, alters its taste and aroma.

尽管习惯改变了，一般消费者的行为还是一样：最重要的需求是得到高质量的产品。
咖啡混合物中的差异化是一个普遍存在的问题。在大多数情况下，Arabica被更便宜的Robusta品种所取代。
由于化合物的巨大差异，不好的混合会影响饮料的质量，改变其味道和香气。

Coffee as an analytic object

Coffee quality can be assessed with modern analytical techniques:
laser-induced-breakdown spectroscopy, high-performance liquid chromatography, gas chromatography and Ion Mobility Spectrometry (IMS).

咖啡质量可以通过现代分析技术进行评估：
激光诱导击穿光谱法、高效液相色谱法、气相色谱法和离子迁移谱法。

Problem statement

Small enterprises can not utilize laboratory-grade techniques due to the high cost of equipment and highly-qualified personnel.
由于设备成本高，人员要求高，小企业不能采用实验室级技术。
The ion mobility spectrometry (IMS) method is successfully used for VOCs identification.
离子迁移谱（IMS）方法已成功地用于挥发性有机化合物的鉴定
Software based on ML approach may be able to determine the quantitative composition of the coffee mix.
基于ML方法的软件可以确定咖啡混合物的定量成分
IMS analysis of coffee mixes with ML-based software may become attractive for small coffee-focused enterprises.
用基于ML的软件对咖啡混合物进行IMS分析可能对专注于咖啡的小型企业具有吸引力。

MCC-GC-IMS 气相离子迁移谱

Sample preparation 样品制备

2维 IMS 图谱

Results 结果

Analysis of obtained 2D spectra with Chemometrics software allowed to achieve 96.6% accuracy.利用化学计量学软件对得到的二维图谱进行分析，准确率达96.6%。

Conclusion 结论

• Meaningful IMS spectra can be obtained by the sampling of VOCs from the vial headspace. 通过从瓶顶空间取样挥发性有机化合物，可获得有意义的IMS光谱。
• Application of Chemometrics software featured with ML algorithms allowed obtaining average accuracy of 96% in the determination of Arabica-Robusta composition in ground coffee mixes. 应用化学计量学软件和ML算法，可获得96%的平均准确度，用于测定研磨咖啡混合物中的Arabica-Robusta成分。
• Inclusion of this kind of software to IMS device software bundle could eliminate the need for the employment of skilled professional for the analysis results interpretation.将这类软件纳入IMS设备软件包可以消除雇用熟练专业人员解释分析结果的需要。
• IMS method may become easy-to-use and cost-effective thus attractive to small coffee-related enterprises. IMS方法可能变得易于使用且具有成本效益，因此对小型咖啡相关企业具有吸引力。