Abstract: In this study, Eichhornia crassipes (water hyacinth) was selected as the experimental material.The effects of pH,temperature,ratio of material to water (ratio of fresh leaves weight to water,m/m) and salt concentration on the extraction yield of crude protein were investigated and optimized.The results of orthogonal experiment showed that the optimal extraction conditions wasA₃B₁C₂D₁, extraction temperature 80 ℃,pH 3.0,salt concentration 2.0%,ratio of material to water 1:2.0.The concentration and extraction yield of crude protein were 43.69% and 14.55%,respectively,under the optimal extraction conditions.The primary and secondary order of factors that affect the extraction yield of leaf protein were pH > temperature > ratio of material to water > salt concentration.This study provided the theory for the development and application of leaf protein of water hyacinth.

Key words: Eichhornia crassipes, leaf protein, extraction process