Study on extraction technology of flavonoids from natural green cotton fiber

Studies have shown that the number of flavonoids between colored cotton and dyed cotton is quite different. Flavonoids content of natural colored cotton is higher than that of white cotton or dyed cotton, so natural colored cotton and dyed cotton can be distinguished by the content of flavone in fibers. Extraction of flavonoids is essential for identification, but there is a lack of simple and trustable extraction method in the market so far for this purpose. This study aim is to explore the most effective method of extracting flavonoids from cotton fibers. Single factor experiment and orthogonal experiment have been designed to get the effect of experimental conditions on the extraction of flavonoids from cotton fibers, and the optimized extraction process has been obtained. Five variables, including the liquid-solid ratio, ethanol concentration, extraction temperature, extraction time, sodium hydroxide concentration, were selected as the main factors, and each factor was studied at four levels. The UV absorbance value at 264?nm was used to evaluate the effect of different extraction conditions on the extraction rate of flavonoids from natural green fibers. The results showed that the extraction efficiency was influenced mostly by ultrasonic temperature, followed by ethanol concentration, the liquid-solid ratio, sodium hydroxide concentration and ultrasonic time. The optimized extraction conditions have been concluded as 1:40 liquid-solid ratio, 50% ethanol concentration, 70??C extraction temperature, 1?h extraction time, 0.15% sodium hydroxide concentration.