“Tea” is a beverage which has a unique taste and aroma. The conventional method of tea manufacturing involves several stages. These are plucking, withering, rolling, fermentation, and finally firing. The quality parameters of tea (color, taste, and aroma) are developed during the fermentation stage where polyphenolic compounds are oxidized when exposed to air. Thus, controlling the fermentation stage will result in more consistent production of quality tea. The level of fermentation is often detected by humans as “first” and “second” noses as two distinct smell peaks appear during fermentation. The detection of the “second” aroma peak at the optimum fermentation is less consistent when decided by humans. Thus, an electronic nose is introduced to find the optimum level of fermentation detecting the variation in the aroma level. In this review, it is found that the systems developed are capable of detecting variation of the aroma level using an array of metal oxide semiconductor (MOS) gas sensors using different statistical and neural network techniques (SVD, 2-NM, MDM, PCA, SVM, RBF, SOM, PNN, and Recurrent Elman) successfully.

中文翻译：

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电子鼻技术监测红茶生产过程

“茶”是一种具有独特味道和香气的饮料。茶的常规制造方法涉及几个阶段。这些是拔毛，枯萎，滚动，发酵，最后是烧制。茶的质量参数（颜色，味道和香气）是在发酵阶段开发的，在发酵阶段，多酚类化合物暴露在空气中会被氧化。因此，控制发酵阶段将导致更稳定地生产优质茶。人们通常将发酵水平检测为“第一”和“第二”鼻子，因为在发酵过程中出现了两个不同的气味峰。当由人决定时，在最佳发酵中检测到“第二”香气峰的一致性就不太强。因此，引入电子鼻以发现最佳的发酵水平，以检测香气水平的变化。在这篇评论中