Determinação de compostos fenólicos em amostras comerciais de chá verde e preto: camellia sinensis(l)

Abstract

The tea produced from the plant C. sinensis is considered the second most consumed drink in the world after water. Tea consumption has been linked to many health benefits. Black and green tea are the main types of tea marketed in the world and in Mozambique the tea with the highest consumption rate is black tea. In the present work, a qualitative phytochemical study was carried out and the total content of phenolic compounds in the national black tea Socone Tea and the imported ones, Five Roses and Green tea, produced from the plant C. sinensis, were determined. In the phytochemical study, to obtain the crude extracts, the teas were subjected to extraction by Soxhlet with the solvent system EtOH / H2O (60:40). The secondary metabolites present in the tea extracts were identified through specific qualitative tests of identification described by Brito et al. (2008), Matos (1997) and Di Stasi (1995). The total content of phenolic compounds was determined using the Folin-Ciocalteu method described by El-Aal and Halaweish (2013). The results of this work show that all tea samples analyzed have secondary metabolites (such as flavonoids, saponins and tannins). Quantitative tests show that imported black tea Five Rose has a higher content of phenolic compounds, with 101.73 ± 5.44 mg of tannic acid equivalents per gram of the sample, green tea, Green tea, with 95.29 ± 1.22 mg of tannic acid equivalents per gram of the sample and the national black tea, Socone tea, has the lowest content of phenolic compounds with 74.14 ± 2.58 mg of tannic acid equivalents per gram of the sample