Abstract:

Dried Asparagus officinalis powder with particle size of 60 mesh was subjected to reflux extraction with aqueous ethanol solution held at a certain temperature for a certain period of time and an extract containing flavonoids and polysaccharides was then obtained. The effects of extraction number and temperature, ethanol concentration, material-to-liquid ratio (g/mL) and length of extraction on flavonoid yield were examined by single factor and orthogonal array design methods to maximize flavonoid yield. The extract was deproteinized by TCA method prior to polysaccharide precipitation with ethanol. A maximum flavonoid yield was obtained by the use of 25-fold volume of 70% ethanol to twice extract the material at 80 ℃ for 2 h each time. The addition of 1.0% TCA provided an optimum deprotainization. The supertanant harvested after centrifugation was added with 3-fold volume of 95% ethanol and thoroughly mixed, and the resultant precipitate was then separated by recentrifugation and vacuum dried to obtain a crude polysaccharide product, with a yield of 1.21%.

Key words: Asparagus officinalis, flavonoids, polysaccharides, extraction