Tea polyphenols are the most abundant and pharmacologically active substances in tea, with antioxidant, anti-inflammatory, anti-cancer and other biological activities. However, the traditional tea polyphenol extraction method has problems such as low efficiency and high pollution, which cannot meet the needs of modern medicine and health industry. In order to solve this problem, this study used laboratory ultrasonic equipment to extract tea polyphenols, aiming to improve the extraction efficiency, reduce environmental pollution, and provide technical support for the further development and utilization of tea polyphenols.
2. Materials and methods.
1.Material.
The tea used in the experiment was commercially available green tea, and the variety was Longjing. The main instrument used in the experiment was laboratory ultrasound equipment (model: US-50).
2.Method.
1) Sample preparation: The purchased green tea is crushed and sieved to obtain tea powder.
2) Ultrasonic extraction: The tea powder was placed in the laboratory ultrasonic equipment, an appropriate amount of methanol-aqueous solution (volume ratio was 3:1) was added, the ultrasonic power was set to 50 W, and the ultrasonic time was 30 minutes.
3) Extraction liquid filtration: The ultrasonic extracted solution is filtered to remove solid impurities.
4) Determination of tea polyphenol content: The content of tea polyphenols was determined by folin-ciocalteu method.
3. Results and Analysis.
1.Ultrasonic extraction efficiency.
Laboratory ultrasonic equipment was used to extract tea polyphenols from tea, and it was found that the efficiency of ultrasonic extraction was significantly higher than that of traditional methods. Under the same conditions, the polyphenol content of ultrasonic extraction was 2153%, compared to 1520%。This shows that laboratory ultrasonic equipment can effectively improve the extraction efficiency of tea polyphenols.
2.Effect of ultrasonic power and time on extraction efficiency.
The experimental results showed that the ultrasonic power and time had an effect on the extraction efficiency of tea polyphenols. Under the condition of ultrasonic power of 50 W and the time of 30 minutes, the extraction efficiency of tea polyphenols was the highest. When the ultrasonic power was lower than 50 W, the extraction efficiency of tea polyphenols increased with the increase of power. When the ultrasonic time was less than 30 minutes, the extraction efficiency of tea polyphenols increased with the increase of time. When the ultrasonic time and power exceeded the optimal value, the extraction efficiency of tea polyphenols decreased. This may be because too high ultrasonic power and time will lead to the destruction and decomposition of other components in the tea leaves, thus reducing the extraction efficiency of tea polyphenols.
3.Effect of methanol-aqueous solution ratio on extraction efficiency.
The experimental results showed that the ratio of methanol to aqueous solution also had an effect on the extraction efficiency of tea polyphenols. When the ratio of methanol to aqueous solution is 3:1, the extraction efficiency of tea polyphenols is the highest. This may be due to the fact that at this ratio, methanol is better able to penetrate into the tea leaves, thus effectively extracting tea polyphenols.
IV. Conclusions. In this study, ultrasonic equipment was used to extract tea polyphenols from tea, and the results showed that ultrasonic extraction could significantly improve the extraction efficiency of tea polyphenols. The experiments also investigated the effects of ultrasonic power, time and methanol-aqueous solution ratio on the extraction efficiency, and found that the optimal conditions were ultrasonic power 50 W, time 30 minutes, and methanol-aqueous solution ratio of 3:1. The results of this study can provide a valuable reference for the industrial production and application of tea polyphenols.