Relationship between Total Phenolic Content, Antioxidant Capacity, Fe and Cu Content from Tea Plant Samples at Different Brewing Times

Simona Dobrinas,Alina Soceanu,Ionela Carazeanu Popovici,Daniela Jitariu,Viorica Popescu

doi:10.3390/pr9081311

Abstract

The purpose of this study was to investigate the antioxidant capacity of different tea plant: mint, linden, chamomile, St. John’s wort, green and black tea in relation to total phenolic content. The antioxidant capacity of the tea infusions at different brewing times was determined using DPPH assay while the total phenolic content (TPC) was assessed using the modified Folin-Ciocalteu method. The results showed that there were significant statistical differences in antioxidant capacity depending on infusion time, according to one-way ANOVA analysis. Leaves used as components of tea infusions were analyzed by FAAS for their content of iron and copper in the dry product and in the infusion. The correlation between TPC and DPPH capacity of tea plant infusions was evaluated by Pearson correlation matrix. Total phenolics compounds content was positively and significantly correlated with DPPH capacity for all infusions time. Significant correlation was observed between TPC and the copper concentration (p < 0.05). Consequently, the correlations between the physicochemical parameters, TPC, DPPH capacity, Fe and Cu content suggested that the TPC may be a good indicator of the DPPH capacity in the tea infusions and also, suggested the influence of antioxidant compounds on mineral bioavailability.

Highlights

Tea is a well-known aromatic drink highly appreciated due to the benefic effect that it has for the human organism and sensory attributes [1,2,3,4]
The results showed that there were significant statistical differences in antioxidant capacity depending on infusion time, according to one-way ANOVA analysis
A correlation study conducted between different groups of the total polyphenol content and antioxidant capacity, and between total polyphenol content and Cu content, showed that the higher the polyphenol content, the higher the antioxidant capacity and higher polyphenol content corresponds to higher copper content in tea infusions

Summary

Introduction

Tea is a well-known aromatic drink highly appreciated due to the benefic effect that it has for the human organism and sensory attributes [1,2,3,4]. Tea has powerful antioxidant characteristics which combats the free oxygen radicals due to the presence of flavonoids [5]. The presence of polyphenols in tea is a quality indicator [6]. Moisture and water extract of tea are parameters used in quality control of tea. Chemical compounds like: polyphenols, sugars, minerals, alkaloids affect the flavor of tea [7]. Moisture content is an important parameter to monitor at different stages in the production of tea [8]. High moisture contents (above 6.5%) are extremely detrimental to tea quality [9]

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Discussion

Conclusion