The efficiencies of different solvents (water, acid and alcohol) in the extraction of caffeine and phenols from leaves of white, black, green and red tea in different solvents: ethanol, isopropanol, methanol and water. Extraction was performed comparative by ultrasonic and by MAE. Determination of the total amount of phenolic compounds was studied comparative using different extraction times 5, 15 and respectively 30 minutes. The microwave irradiation shortens time necessary to extract phenols and caffeine from tea samples (between 30 and 50 seconds). The results of the comparison investigation are presented in the figure 1.

2. Conclusion

Chromatographic determination of phenolic compounds isolated from the tea samples by ultrasonic and MAE extraction is comparable. The difference between the two methods of extraction consists in extraction time and amount of solvents used. Also, the yield for MAE was about 20% is 20% higher than that of the ultrasonic extraction.

Figure 1. Comparison between the two extraction methods

Author details

Adina-Elena Segneanu, Paulina Vlazan,

Paula Sfarloaga and Iaon Grozesku

National Institute of Research and Development for Electrochemistry and Condensed Matter — INCEMC Timisoara, Romania

Florentina Sziple

Eftimie Murgu University, Resita, Romania

Vasile Daniel Gherman

Politehnica" University of Timisoara, Romania