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Evaluation of analytical methods to determine regulatory compliance of coffee leaf tea
1, 2 , 3, 4 , 3 , 1 , 4 , 3 , 4 , * 1
1  Chemisches und Veterinäruntersuchungsamt (CVUA) Karlsruhe, Weissenburger Strasse 3, 76187 Karlsruhe, Germany
2  Hochschule für angewandte Wissenschaften Coburg, Friedrich-Streib-Strasse 2, 96450 Coburg, Germany
3  Coffee Consulate, Hans-Thoma-Strasse 20, 68163 Mannheim, Germany
4  Department of Flavor Chemistry, University of Hohenheim, Fruwirthstr. 12, Verfügungsgebäude, 221, 70599 Stuttgart, Germany
Academic Editor: Oscar Nuñez

Abstract:

The leaves of the coffee plant (genus Coffea) are traditionally used in several countries worldwide to prepare tea-like beverages using aqueous infusion in hot water. Since 1 July 2020, the placing on the market of coffee leaf tea was authorized in the European Union (EU) under the framework of the novel food regulation. The implementing regulation for coffee leaf tea established several conditions of use, including maximum amount of dried leaves per litre of water, a necessary pasteurisation step and several chemical requirements including maximum levels for chlorogenic acid, caffeine and epigallocatechin gallate. To date, there are no standard methods available to control these parameters to check the regulatory compliance of coffee leaf tea. In this presentation, we have for the first time evaluated standard methods for Camellia sinensis tea analysis for transferability to coffee leaf tea. The results showed that the methods for polyphenol and catechin analysis could be transferred without modifications to coffee leaf tea. The only difference found was a much lower content of some catechins in coffee leaf tea compared to Camelia sinensis tea, but the methods were clearly applicable to be used to control the EU’s maximum limits for coffee leaf tea. None of the samples obtained from India and El Salvador exceeded the limits and all were found to comply with the EU regulation. Furthermore, standard European tea brewing methods using 90-95°C hot water will ensure the EU’s necessary pasteurisation conditions (at least 71°C for 15 seconds).

Keywords: coffee by-products; coffee leaves; tea; analysis; HPLC; food control; novel food
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