Optimization of Enzymatic Extraction of Dietary Fiber from Zizyphus jujube and Its Antioxidant Activity

The dietary fiber was extracted from Zizyphus jujube.The processing of enzyme extraction of dietary fibers was studied by single factor experiments and response surface analysis method. The optimal process parameters of the extraction process were:Enzyme volume 1.5 mg·mL^-1,temperature 50℃,liquid to solid ratio 9:1 mL/g and extraction time 45 min. Under these conditions,the yield of dietary fiber from Zizyphus jujube was 9.18%. The water-holding capacity,oil-holding capacity,expansive force and cation exchange capacity of enzyme extraction were stronger than water extraction with significant differences(P<0.05). The dietary fiber from Zizyphus jujube revealed strong scavenging capacity against DPPH free radicals with an IC₅₀ was 0.227 mg·mL^-1.The study revealed that the dietary fiber from Zizyphus jujube had high antioxidant activity in vitro and could be used as a natural antioxidant.