Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas

  • Tânia Santos de Almeida Universidade Lusófona’s Research Center for Biosciences and Health Technologies https://orcid.org/0000-0002-5150-9910
  • Maria Eduarda Machado Araújo Universidade de Lisboa, Faculdade de Ciências
  • Lucía González Rodríguez Universidade de Lisboa, Faculdade de Ciências
  • Ana Júlio Universidade Lusófona’s Research Center for Biosciences and Health Technologies
  • Beatriz Garcia Mendes Universidade Federal de Santa Catarina
  • Rui Miguel Borges dos Santos Universidade de Lisboa, Faculdade de Ciências
  • José Artur Martinho Simões Universidade de Lisboa, Faculdade de Ciências
Keywords: Black tea, Green tea, Antioxidant activity, α-Glucosidase activity, Water mineralization

Abstract

The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the α-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower mineralized waters. Tea bags also evidenced higher antioxidant activity than loose-leaf samples. Under the same conditions (90 ºC and five minutes of infusion time) green tea contains almost twice the quantity of polyphenols and the free radical scavenging ability of black tea. In the α-glucosidase assay all infusions were active (97-100 %). Furthermore, HPLC allowed to identify some of the polyphenols present in both teas and to monitor their composition change with time. After twenty-four hours, the antioxidant activity was maintained without significant changes, but a small decrease in enzyme inhibition was observed, although this activity was still very high.

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Published
2019-11-29
How to Cite
Almeida, T., Araújo, M. E., Rodríguez, L., Júlio, A., Mendes, B., Santos, R., & Simões, J. A. (2019). Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas. Brazilian Journal of Pharmaceutical Sciences, 55, e17695. https://doi.org/10.1590/s2175-97902019000117695
Section
Articles