A Non-Volatile Study of Teas Using Modern Analytical and Sensory Techniques

摘要

The differentiation of a variety of teas was carried out based on the contents of their taste-active components. Forty-four taste active components including the following five groups: amino acids (twenty naturally-occurring amino acids, theanine and ornithine), organic acids, sugars, phenolic compounds and purine alkaloids were determined by liquid chromatography in tea infusions. To further bridge the gap between pure analytical chemistry and human taste perception, the dose-over-threshold (DOT) factors were calculated on the basis of a dose/threshold relationship for these taste-active components, and thus taste spider charts were constructed. Analyses of these taste spider charts for different tea infusions suggested that it not only provides an easy and unbiased comparison and classification for multiple tea samples in taste, but also is able to narrow the number of key taste compounds from forty-four to thirteen as chemometric descriptors for classification purposes of different tea varieties. Thus, an analytical method was developed to quantify these taste active components by NMR spectroscopy, and in conjunction with the sensory spider charts, could lead to a more rapid and unbiased assessment for the taste of a variety of teas.