Differentiation of fermented tea varieties cultured in Assam and Darjeeling using MALDI-ToF mass spectrometry

Kaufmann M., Wagner L., Lange F., Bergmann M.
Differentiation of fermented tea varieties cultured in Assam and Darjeeling using MALDI-ToF mass spectrometry
European Food Research and Technology 248, 1991–2002 (2022)

Official food control is increasingly facing the task of finding instrumental analytical methods to verify/falsify food authenticity that need to be suitable for laboratory routine. While numerous methods for the identification of animal species are available in official food authenticity control, only few methods deal with the identification of food crops—apart from allergens. To partly close this gap, we present a quick and easy procedure based on matrix-assisted LASER desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) for the identification of Camellia sinensis plant material and the differentiation between fermented tea varieties cultured in Assam (Camellia sinensis var. assamica; northeast India) and Darjeeling (Camellia sinensis var. sinensis; northwest India). MALDI-TOF mass spectra of the protein-rich extracts of 37 fermented tea samples obtained from tea gardens in Assam and Darjeeling were analyzed using multivariate statistical methods such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The resulting classification model differentiates reliably between fermented teas obtained from Assam and Darjeeling. Even the differentiation of fermented Assam/Darjeeling mixtures from pure Darjeeling and Assam teas, respectively, is to some extent possible.