Evaluation of carbohydrates and quality parameters in six types of commercial teas by targeted statistical analysis.

The content of low molecular weight carbohydrates (LMWC) of six types of tea produced from the leaves of Camellia sinensis were analyzed by hydrophilic interaction chromatography (HILIC) coupled to mass spectrometry. Quantities of sucrose, glucose, fructose, myo-inositol, maltose, mannitol, raffinose, galactinol, and stachyose were determined in samples of white, yellow, green, black, oolong, and dark tea. Sucrose was the most abundant carbohydrate in all types of tea. The concentration of all measured carbohydrates except mannitol was lowest in dark tea samples. Correlation analyses using quantitative data of LMWCs, antioxidant activity, and color parameters were performed on black tea samples to evaluate the interaction of different quality parameters. Carbohydrates depletion was observed during tea processing with formation of Amadori compounds with theanine.

Characterization of commercial green tea leaves by the analysis of low molecular weight carbohydrates and other quality indicators.

A comprehensive characterization of commercial green tea (CGT) with the employment of independent variables such as low molecular weight carbohydrates (LMWC), soluble solids, color and antioxidant capacity has been performed in this manuscript. Within the manuscript, a convenient HILIC-MS method, suitable to perform a simultaneous identification and quantification of all mono-, di-, oligosaccharides and cyclitols observed in green tea was introduced. The method covers all key analytes in a single chromatographic analysis. Fifty-six samples from different origins (n = 10) were evaluated to explore differences based on origin. In addition, commercial samples processed by pan-firing and steaming were used for comparative purposes, allowing the identification of putative processing markers. The results obtained contribute to gain a better knowledge of the variations, according to origin and processing, in composition and quality of CGT, commodity widely appreciated by the consumers.