落葵种子蛋白提取工艺优化及其抑菌和抗氧化特性分析

Optimization of extraction technology for Basella alba L. seed protein and its bacteriostasis and antioxidant properties

【目的】优化落葵(Basella alba L.)种子蛋白提取工艺,并分析其抑菌和抗氧化特性,为开发利用落葵种子蛋白提供参考依据。【方法】采用盐析法提取落葵种子蛋白,以大肠杆菌为指示菌,通过比较不同浸泡缓冲液、浸泡时间、料液比和硫酸铵饱和度提取蛋白的抑菌效果,选出影响较大的因素进行正交试验从而确定最佳提取方案;通过牛津杯抑菌试验评价落葵种子蛋白对33株菌的抑菌效果,同时对其还原力及清除DPPH自由基能力进行测定。【结果】3个因素对落葵种子蛋白提取效果的影响排序为料液比>硫酸铵饱和度>浸泡时间;其最佳提取工艺为:浸泡时间14 h、料液比1∶8、硫酸铵饱和度95%,在此条件下提取物的蛋白含量可达33.00 mg/mL,大肠杆菌抑菌圈直径为19.68 mm。落葵种子蛋白抑菌范围较广,对红酵母、枯草芽孢杆菌、金黄色葡萄球菌、单增李斯特菌、藤黄球菌、副溶血性弧菌、假单胞菌、气单胞菌、大肠杆菌等33株菌均具有良好的抑菌效果。落葵种子蛋白还原力测定的半最大效应浓度(EC_(50))为4.867 mg/mL,对DPPH自由基清除率的半抑制浓度(IC_(50))为27.817 mg/mL。【结论】落葵种子蛋白具有良好的抑菌效果和抗氧化特性,有作为天然抑菌剂和抗氧化剂的潜在价值。

[Objective]The extraction technology of Basella alba L.seed protein was optimized,its bacteriostasis and antioxidant properties were analyzed.It provided theoretical basis for the development and utilization of B.alba seeds.[Method]Salting-out method was used to extract protein of B.alba seeds.Escherichia coli was used as indicator bacteria.The antimicrobial effect of protein extracted by different soaking buffers,soaking times,material-liquid ratios and ammo-nium sulfate saturation was compared,and the influencing factors were selected for orthogonal test to determine the best extraction scheme.Antimicrobial effect of B.alba seed protein against thirty-three strains of bacteria were tested in Oxford cup.The reducing power and DPPH free radicals scavenging ability were also studied.[Result]Three prominent influen-cing factors were selected and their effects on B.alba seed protein extraction were:material-liquid ratio>saturation of ammonium sulfate>soaking time.The optimum extraction conditions were as follows:soaking time 14 h,ratio of material to liquid 1∶8 and saturation of ammonium sulfate 95%.Under such condition,the extracted protein content was 33.00 mg/mL and the diameter of the inhibition zone for E.coli was 19.68 mm.The inhibition zone of B.alba seed protein was large,it had fine inhibition effects against 33 strains of bacteria such as Rhodothece glutinis,Bacillus subtilis,Staphylococcus aureus,Listeria monocytogenes,Micrococcus luteus,Vibrio parahemolyticus,Pseudomonas aeruginosa,Aeromonas and E.coli.Half-maximal effect concentration(EC50)of B.alba seed protein reducing ability was 4.867 mg/mL,and its half-inhibitory concentration(IC50)against DPPH radical scavenging rate was 27.817 mg/mL.[Conclusion]B.alba seed protein has fine antibacterial effect and antioxidant property,and has potential value as a natural antimicrobial and antioxidant.