Objective: To optimize alkali extraction and acid precipitation process of water-soluble protein from Schisandrae Chinensis Fructus. Method: With extraction rate of protein as index

single factor tests and orthogonal design were adopted to optimize extraction process of water-soluble protein by taking solid-liquid ratio

pH of extract

extraction temperature and time as factors

isoelectric point and molecular components of water-soluble protein were analyzed.Coomassie brilliant blue Bradfrod was employed to determine protein content in extract. Result: Isoelectric point of water-soluble protein was 3.4.Optimum extraction conditions was as following:solid-liquid ratio of 1:35

pH of extract 9.5

extraction temperature at 35 ℃

extraction time of 2 h.Extraction rate of water-soluble protein was up to 43.62%.SDS-PAGE analysis showed that majority subunits of water-soluble protein were 50

40

38

21 kDa

and a small amount of 18

16 kDa. Conclusion: This optimized extraction process is stable and feasible

this study provides a reference for development of functional health food by water-soluble protein from Schisandrae Chinensis Fructus.