Optimization of mechanochemical assisted extraction process of total flavonoids from tea dust by response surface methodology

The mechanochemical assisted extraction was adopted to extract total flavonoids from tea dusttea by products in this paper. Based on effect of alkali additives content, ethanol concentration, materialto-solvent ratio and extraction times, extraction temperature and solution pH on the extraction efficiency of total flavonoids in the single factor experiment, the effects of alkali additives content, ethanol concentration and solid-to-solvent ratio and extraction time on the extraction efficiency of total flavonoids were investigated by the Box-Behnken experiment design principle and the response surface analysis and a quadratic polynomial model was established and validated to be highly significant and allow the prediction of the extraction efficiency of total flavonoids. The optimum conditions for the extraction of total flavonoids were 40% ethanol as the extraction solvent at a solid-to-solvent ratio of 1:53(g/mL), alkali agent content of 6.3%, pH of 4.0, 50 ℃ and extracting 3 times. The extraction efficiency of total flavonoids was 9.08% under these conditions. The extraction efficiency of total flavonoids up to 8.902% and 7.858% when the solvent was 20% ethanol and distilled water, respectively. Comprehensive comparison, the extraction efficiency of total flavonoids increased less than 1.3% with alcohol than water. Therefore, the extraction with water as the extraction solvent is more industrial production advantage in the actual production from the raw material costs and the sustainable development. The mechanochemical assisted extraction have less time, more saving energy and higher extraction efficiency than hot reflux extraction.