Metabolomics Profiling of Roasted Stem Tea Using Gas Chromatography-Mass Spectrometry and a Sensory Test

Roasted tea is manufactured by roasting green tea at a high temperature and has characteristic flavors (roasted, savory, or sweet) that complement Japanese-style food. Here, we evaluated the sensory quality for six kinds of roasted stem tea products using a sensory test, the rank-rating method, of 52 adolescent panelists. We then elucidated and analyzed the chemical components in these products by gas chromatography-mass spectrometry and principal component analysis. We found that the preferred products were located near the center of the principal component analysis score plot, indicating that the position in the plot was associated with the sensory score of roasted stem tea. We then used these findings to build a predictive model of sensory scores using orthogonal partial least squares regression analysis. This showed that the predicted sensory score was higher when certain pyrazines were present and lower when aldehydes and sugars were present. This is the first study to demonstrate a relationship between the chemical components of roasted stem tea and its sensory score based on the palatability of adolescents for it using metabolomics profiling.