Chemical profiles, dissolution patterns, and in vitro bioactivities of selenium-enriched green teas: impact of brewing conditions

Abstract

The dissolution patterns of different teas determine the sensory quality and health attributes of the tea infusion. In this study, the chemical profiles of two typical selenium-enriched green teas, Xiazhou Bifeng (Se-BF), Enshi Yulu (Se-YL), and their corresponding regular green teas (BF and YL) were determined. Under the application of selenium fertilizer, the contents of caffeine, polyphenols, and gallic acid decreased, while the contents of theaflavins, theabrownins, and chlorophylls increased. The selenium content in BF and YL is 0.05−0.16 mg/kg and 0.33−0.43 mg/kg respectively, while after the application of exogenous selenium, the selenium content in Se-BF and Se-YL reached 1.28 to 2.17 mg/kg and 0.37−2.23 mg/kg respectively. The dissolution patterns of Se-BF and Se-YL were investigated under different brewing conditions (temperature and duration), and the main components of Se-YL were more easily dissolved out than Se-BF, which might be attributed to the steaming process of Se-YL. Based on the sensory evaluation of tea infusion, 100 °C and 5 min were the optimal brewing conditions. Based on a daily tea consumption model, the increased brewing time reduced the content of dissolved components in tea infusions, along with the decreased in vitro antioxidant and hypoglycemic activities. Collectively, Se-YL demonstrated superior sensory and nutritional attributes compared to Se-BF. This study explored the influence of brewing conditions on the dissolution patterns and in vitro bioactivities of selenium-enriched green teas, providing guidance for scientific tea brewing and consumption.

Keywords

Selenium-enriched green teas / Brewing conditions / Chemical profiles / Dissolution patterns / in vitro bioactivities

Author contributions

The authors confirm contribution to the paper as follows: conceptualization, writing - draft manuscript preparation: Wei Y; investigation and methodology: Zhang D; writing manuscript revision: Wei Y, Liang Y, Shi J, Wei X, Wang Y; investigation: Wei K, Peng L; data analysis: Gu H; methodology: Ma P; software and validation: Wang Q, Zhu Z; supervision, funding, administration: Wei X, Wang Y. All authors reviewed the results and approved the final version of the manuscript.

Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

The authors are grateful for financially sponsorship by Shanghai Agricultural Science and Technology Innovation Project (2023-02-08-00-12-F04598), National Key R&D Program of China (2022YFD2101104), Shaanxi Province key core technology project (2024NC-GJHX-15), National Natural Science Foundation of China (32172223), New Young Teachers Program of Shanghai Jiao Tong University (24X010500154) and China Postdoctoral Science Foundation (BX20220201, 2021M702140).

Conflict of interest

The authors declare that they have no conflict of interest.

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