| 摘要 |
[Objectives] To investigate the concentration of tea polyphenols in the tea infusion, evaluate their antioxidant and antibacterial activities, optimize the extraction conditions of tea polyphenols, and provide a foundation for their development as natural antioxidants and antibacterial agents. [Methods] Single-factor tests and orthogonal experiments were performed to examine the effects of brewing temperature, duration, and frequency on the extraction of tea polyphenols. Antioxidant activity was assessed using the DPPH radical scavenging assay, reducing power assay, and hydroxyl radical scavenging assay. The antibacterial activities of the tea infusion against Escherichia coli, Bacillus thuringiensis, Penicillium, and Saccharomyces were evaluated through spectrophotometry. [Results] The concentration of tea polyphenols increased with rising brewing temperature and duration but decreased with an increase in brewing frequency. The relative influence of these factors was ranked as follows: brewing duration> brewing frequency > brewing temperature. The optimal brewing conditions were determined to be 100 °C, 15 min, and a single brewing cycle. Under these conditions, the tea polyphenol concentration reached 0.788 4 mg/mL. Additionally, the DPPH free radical scavenging rate, reducing power, and hydroxyl radical scavenging rate of the tea infusion all exhibited a positive correlation with tea polyphenol concentration. The antibacterial activity of the tea infusion against four microorganisms, in descending order of efficacy, was B. thuringiensis, E. coli, Penicillium, and Saccharomyces. [Conclusions] The extract of Fenghuang Dancong tea exhibits significant antioxidant and antibacterial properties. Its efficacy is positively correlated with the concentration of tea polyphenols, demonstrating a stronger inhibitory effect on bacteria compared to fungi. |
