Identification, quantitation, and method validation for flavan‐3‐ols in fermented ready‐to‐drink teas from the Italian market using HPLC‐UV/DAD and LC‐MS/MS

Abstract

The present study is focused on flavan-3-ols characterizing the antioxidant properties of fermented tea (Camellia sinensis). These bioactive compounds, object of nutritional claims in commercial products, should be quantified with rigorous analytical procedures whose accuracy and precision have been stated with a certain level of confidence. An HPLC-UV/ DAD method, able to detect and quantify flavan-3-ols in infusions and ready-to-drink teas, has been developed for routine analysis and validated by characterizing several performance parameters. The accuracy assessment has been run through a series of LC-MS/MS analyses. Epigallocatechin, (1)-catechin, (À)-epigallocatechingallate, (À)-epicatechin, (À)-gallocatechingallate, (À)-epicatechingallate, and (À)-catechingallate were chosen as markers of the polyphenolic fraction. Quantitative results showed that samples obtained from tea leaves infusion were richer in polyphenolic antioxidants than those obtained through other industrial processes. The influence of shelf-life and packaging material on the flavan-3-ols content was also considered; markers decreased, with an exponential trend, as a function of time within the shelf life while packaging materials demonstrated to influence differently the flavan-3-ol fraction composition over time. The method presented here provides quantitative results with a certain level of confidence and is suitable for a routine quality control of iced teas whose antioxidant properties are object of nutritional claim.

Tutorial review on validation of liquid chromatography–mass spectrometry methods: Part I

“…In addition, there is a large number of articles demonstrating validation of LC-ESI-MS methods for practical analytical tasks with respect to certain validation guidelines such as FDA [68][69][70][71][72], ICH [73][74][75] Eurachem [76][77][78][79][80][81][82][83], EMA [84][85][86], IUPAC [87][88][89] or SANCO [90,91]. However, in most cases not all parameters are investigated.…”

Antioxidant Capacity of Tea

“…Tea beverages are produced on the basis of tea extracts or tea infusions prepared as a part of beverage manufacturing process and available on the market bottled or canned (Cordero et al, 2009). Tea beverages are produced on the basis of tea extracts or tea infusions prepared as a part of beverage manufacturing process and available on the market bottled or canned (Cordero et al, 2009).…”

“…The content of catechins in fermented tea beverages of eight brands available on the Italian market was highly variable (Cordero et al, 2009). The sample richest in catechins, (> 200 μg/ml) was produced from tea leaf infusion.…”

“…The shelf-life of the products is usually 12 months; nevertheless, product aging during that time was found to be extensive. When PET, polystyrene glass, and cans used as packaging for fermented tea drinks originating from the same batch were compared, the highest storage stability was found for drinks in cans (Cordero et al, 2009). Tea drinks were stored in the absence of light at a temperature of 3°C and catechins were found to be stable up to 6 weeks, and after that time the degradation appeared to a greatest extent in retortable pouch > PET > glass (Kim et al, 2011b).…”

Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

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