Optimization of extraction process of polysaccharides from Metaplexis japonica Makino nutshell and evaluation of antioxidative activity

Based on the single factor experiments,the response surface methodology(RSM) was employed to optimize the extraction conditions of polysaccharides from Metaplexis japonica Makino nutshell(MJNP) and its antioxidant activity was primarily evaluated. The results of optimum extraction conditions were as follow :the ratio of water to raw material 1 ∶18(g/m L),extraction temperature 86 ℃,extraction time 3 h and number of extraction 3 times. Under these conditions,the average extraction yield was 11.22%. The results of antioxidation experiments showed that the highest scavenging capacity of polysaccharides against O2-,DPPH was 80.61%,73.01% respectively. The optimization of MJNP extraction process technology was reasonable and feasible,MJNP had stronger antioxidant activity.