富硒花生分离蛋白制备工艺的优化

Preparation of Isolate Protein from Selenium-enriched Peanut

针对富硒花生多以初级产品形式流向市场,深加工产品少的现状,本试验对高附加值的富硒花生分离蛋白制备工艺进行系统研究。以富硒花生为原料,采用超高压辅助提取技术对花生油脂进行充分地脱除,并通过响应面设计优化富硒花生分离蛋白的提取工艺,初步探明富硒花生在不同加工阶段硒含量的变化。结果表明,超高压条件:压力300 MPa,时间5 min,超高压辅助结合恒温水浴浸提6 h的脱脂处理可大幅提高脂肪脱除率;在蛋白提取工艺中,基于单因素试验结果选取提取液pH值、料液比、提取时间3个因素作为响应面优化因素,最终获得最佳提取工艺:pH 9.1,时间97 min,液料比1∶11 g/m L;富硒花生在不同加工阶段硒含量的变化表明,通过此加工工艺,富硒花生分离蛋白粉能很好地保持原料中的硒含量,尤其是有机硒含量,是一种具有高营养价值的深加工富硒花生产品。

Selenium is an essential micronutrient required at trace levels for human health,which is often supplied by natural plants or animals to humans at levels too low for optimum health.In recent years,there has been growing interest in producing selenium-enriched agricultural products,such as selenium-enriched peanut,selenium-rich rice,selenium-enriched apple,etc.Selenium-enriched peanut,a kind of selenium-enriched agricultural products,for example,planted widely in ecological agricultural base,like Enshi of Hubei,Ziyang county of Shaanxi province,Fengcheng of Jiangxi.However,the concentration of the industry is not high,and products are mostly low value-added primary ones.For developing high value-added production of selenium-enriched products,the process optimization was necessary.In the paper,with selenium-enriched peanut（0.25 ± 0.05） mg Se/kg peanut as raw material,the isolate protein was prepared by using high hydrostatic pressure assisted extraction technology for removing selenium-enriched peanut oil,and alkaline extraction and acid precipitation method for protein extraction,meanwhile the content of selenium was tracing analyzed.Results showed that during the lipid extraction process assisted with high hydrostatic pressure of 300 MPa and5 min,combined with water bath in 40 ℃ extracting 6 h,peanut oil could be removed efficiently.The treatment of 300 MPa high hydrostatic pressures could not only greatly shorten the process time,but also make emulsification property and emulsification stability achieve better.While isolate protein extracting,the effect of the extracting solution pH,extraction time,extraction temperature,solid-to-liquid ratio and the acid precipitator pH on the extraction yield of protein were conducted using single factor experiment respectively.On this basis,50 ℃ of extraction temperature and 5.5 of the acid precipitator pH was obtained,then the optimal factors including the extracting solution pH（X_1）,extraction time（X_2）,solid-to-liquid ratio（X_3） were investigated by Box-Behnken surface response design method.The quadratic multiple re gression equation was established as Y（%）=86.30＋1.19 X_1＋1.77 X_2＋0.47 X_3＋0.22 X_1X_2-0.53 X_1X_3＋0.55 X_2X_3-2.09 X_1~2-1.48 X_2~2-0.87 X_3~2,while the optimum conditions for the protein extraction were obtained by the regression equations ： 9.1 for the extracting solution pH,97 min of extraction time,1∶11 g/m L of solid-to-liquid ratio,and under which optimum conditions,the yields of protein could be reached 86.92% ± 0.17%.Thus optimum technology can reduce the extraction time and improve the efficiency of extraction significantly.At last,the change of Se content in various process stages was determined by ICP-MS.It indicated that selenium existed mainly in deoiled peanut,and the average value of total selenium content of isolate protein by optimized way could be reached to 0.37 mg/kg,among which about 0.35 mg/kg was organic selenium,representing 95% of the total selenium.In general,selenium-enriched isolate protein was a kind of high value-added production of selenium-enriched peanut,and had good application prospects.