Article

Black tea: chemical analysis and stability. Food Funct 4:10-18

Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901, USA. .
Food & function 10/2012; 4(1). DOI: 10.1039/c2fo30093a
Source: PubMed

ABSTRACT

Tea is the most popular flavored and functional drink worldwide. The nutritional value of tea is mostly from the tea polyphenols that are reported to possess a broad spectrum of biological activities, including anti-oxidant properties, reduction of various cancers, inhibition of inflammation, and protective effects against diabetes, hyperlipidemia and obesity. Tea polyphenols include catechins and gallic acid in green and white teas, and theaflavins and thearubigins as well as other catechin polymers in black and oolong teas. Accurate analysis of black tea polyphenols plays a significant role in the identification of black tea contents, quality control of commercial tea beverages and extracts, differentiation of various contents of theaflavins and catechins and correlations of black tea identity and quality with biological activity, and most importantly, the establishment of the relationship between quantitative tea polyphenol content and its efficacy in animal or human studies. Global research in tea polyphenols has generated much in vitro and in vivo data rationally correlating tea polyphenols with their preventive and therapeutic properties in human diseases such as cancer, and metabolic and cardiovascular diseases etc. Based on these scientific findings, numerous tea products have been developed including flavored tea drinks, tea-based functional drinks, tea extracts and concentrates, and dietary supplements and food ingredients, demonstrating the broad applications of tea and its extracts, particularly in the field of functional food.

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    • "The orange red or brown color and astringent taste of black tea infusion is attributed to TFs as TRs contribute to rusty color and richness taste [4] [10]. There are four major TFs in black tea and oolong tea, that is, theaflavin (TF1), theaflavin-3-gallate (TF2a), theaflavin-3 -gallate (TF2b), and theaflavin-3,3 -digallate (TF3) [6] [11] [12]. Chemical structures of various types of tea catechins and theaflavins are shown in Fig. 1. "
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    ABSTRACT: Among six major types of tea (white, green, oolong, yellow, black, and dark teas) from Camellia sinensis, oolong tea, a semi-fermented tea, with its own unique aroma and taste, has become a popular consumption as indicated by the increasing production. Representing the characteristic flavonoids of oolong tea, theasinensins are dimeric flavan-3-ols. Many recent studies have indicated that oolong tea and theasinensins possess several health benefit properties. We consider it significant and necessary to have a comprehensive review in the recent advances of oolong tea. Therefore, the aim of the present review is to provide a new perspective on oolong tea and its characteristic phytochemicals, theasinensins associated with health benefits, molecular action pathway, and chemical mechanism of theasinensin formation from scientific evidences available on the literature. Furthermore, the chemical characterization of the oxidation products and the model oxidation system to the chemical changes of theasinensins are also discussed.
    Full-text · Article · Nov 2015
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    • "The acetone solution in each fraction was concentrated by a rotary evaporator and lyophilized by a freeze dryer. Their purity (at least 98%) was confirmed by HPLC method (Li et al., 2013). 2.5. "

    Full-text · Article · Jun 2015 · Antiviral Research
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    • "The acetone solution in each fraction was concentrated by a rotary evaporator and lyophilized by a freeze dryer. Their purity (at least 98%) was confirmed by HPLC method (Li et al., 2013). 2.5. "

    Full-text · Article · Jun 2015 · Antiviral Research
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