Abstract
Objective: This study estimated the Permangante Index (IKMnO4) and evaluated its correlation with parameters as total phenols (FT) and total antioxidant activity (TAA) of commercial teas of Camellia sinensis, fermented, unfermented and blended with other plants.Methods: The aqueous extracts were prepared from commercial samples of green and black teas, green tea blended with lemon (Camellia sinensis with Citrus limonium), green tea blended with mint (Camellia sinensis with Mentha piperita), green tea blended with peach (Camellia sinensis with Prunus persica) and green tea blended with orange (Camellia sinensis with Citrus sinensis). The Permangante index was determined by titrating the tea extract with potassium permanganate solution according to AOAC method (AOAC, 1980) with modifications. The concentration of phenols in the extracts was determined by spectrophotometry according to the standard procedure of Folin-Ciocalteau. The antioxidant activity of the extracts was evaluated using the radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. All the determinations were performed in triplicate, and the results presented as mean ± standard deviation (SD). The data were evaluated by univariate statistical analysis (ANOVA), F-test and mean test (Tukey´s test) for comparative results. Pearson’s correlation was used to measure the degree of linear correlation and the quantitative variables were from a normal population.Results: The results for Permanganate Index show a variation ranged from 0.40 to 0.80 mEq/l. The ANOVA analysis to IKMnO4 shown there is significant statistically difference at the 5% probability level (p < 0.05) between the types of tea as well as the amount of herb used to prepare the infusion. Therefore, it was observed that there significant contrast between tea extracts, the mixture of different plants in blended extracts as well as the tea manufacture process affect the polyphenols tannins content influencing the permanganate index parameter. Studies correlation shown strong correlations (r > 0.7) among the parameters. For the Camellia sinensis extracts the high correlations between IKMnO4 and TAA; FT and TAA demonstrates the suitability of the permanganate index in the evaluation of antioxidant activity.Conclusion: The results suggest that the Permanganate Index could be used for quality control of tea as an additional parameter.
Highlights
Tea has great economic importance in the area of functional foods to be second most consumed beverages in the world after water
The extracts were prepared from commercial samples of green and black teas, green tea blended with lemon (Camellia sinensis with Citrus limonium), green tea blended with mint (Camellia sinensis with Mentha piperita), green tea blended with peach (Camellia sinensis with Prunus persica) and green tea blended with orange (Camellia sinensis with Citrus sinensis)
It was necessary to perform a second determination by difference, after the separation of tannin content, to avoid these interferents can be analysed resulting in an overestimation of the polyphenol content
Summary
Tea has great economic importance in the area of functional foods to be second most consumed beverages in the world after water. Infusions of leaves of Camellia sinensis are well recognized because of its effect therapeutics. The health benefits of green tea have been attributed to the high content of polyphenols in the drink. Camellia sinensis plants contain large amounts of various phenolic compounds as flavonoids, phenolic acids, tannins and others. The major polyphenols compounds present in the plant are phenolic acids, e. The tannins naturally occurring in tea are condensed tannins, polymeric structures resulting from the polymerization of elementary phenol compounds, polyhydroxyflavan-3-ols known as the catechins. Phenolic fraction in Camellia sinensis commercial extract are responsible for important quality attributes such as flavour, taste and color [2] and influence the tea industry in relation to market value
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