超声波辅助碱法提取大球盖菇蛋白质工艺的优化

Optimization of extraction process of Stropharia rugosoannulata protein by ultrasonic-assisted alkali

目的优化超声波辅助碱法提取大球盖菇蛋白质工艺,并测定蛋白质的热稳定性。方法以烘干大球盖菇粉为原料,在pH 12、料液比1:30 g/mL碱法提取的基础上,进行超声波辅助处理,研究超声功率、时间及温度等因素对大球盖菇蛋白质提取率的影响。采用差示扫描量热法(differe ntial scanning calo rimeter,DSC)测定提取蛋白的热稳定性。结果超声波辅助碱法提取大球盖菇蛋白质的最佳条件:超声功率140 W、超声温度40℃、超声时间20 min,3次重复验证蛋白质提取率为42.14%±0.47%,与预测值之间差异不显著(P>0.05)。超声条件对蛋白提取率的贡献为:功率>时间>温度。蛋白质等电点为pH 4.2,热变性温度(denaturation temperature,T_d)为63.14℃,热焓ΔH为1.701 J/g。结论超声波辅助碱法是提取大球盖菇蛋白的一种有效方法,提取的蛋白质具有一定的热稳定性。

Objective To optimize the extraction technology of protein of Stropharia rugosoannulata by the ultrasonic-assisted alkali and clarify the thermal stability of protein. Methods The preparation of protein from dried Stropharia rugosoannulata powder by the ultrasonic-assisted treatment was conducted on the basis of alkaline extraction under pH 12 and solid-liquid ratio of 1:30 g/mL, the effect of ultrasonic power, time and temperature on the extraction rate of Stropharia rugosoannulata protein were studied by the extraction rate of protein, and the thermal stability was determined by differential scanning calorimeter(DSC) method. Results The optimal extraction conditions by response surface analysis were as follows: ultrasonic power 140 W, ultrasonic temperature 40 ℃, ultrasonic time 20 min. The protein extraction rate was 42.14%±0.47% in the actual trials, which was not significantly different from the predicted value(P>0.05). Ultrasonic conditions affect the extraction rate of protein, ultrasonic power had the greatest influence, ultrasonic time was the second, and ultrasonic temperature was the least. The isoelectric point of Stropharia rugosoannulata protein was measured to be pH 4.2. The denaturation temperature was 63.14 ℃, and the denaturation heat was 1.701 J/g. Conclusion Ultrasonic assisted-alkali extraction is an effective method for extraction of Stropharia rugosoannulata protein, and the extracted protein had certain thermal stability.