三相分配法提取青稞β-葡聚糖工艺优化及其分子量分布研究

Optimization of the Extraction Process of Highland Barleyβ-glucan by Three-phase Partitioning and Its Molecular Weight Distribution

采用超声波结合酶法预处理辅助三相分配法(UCWEPATPP)同时提取青稞中的青稞β-葡聚糖、青稞蛋白和青稞油。在单因素实验的基础上,以青稞β-葡聚糖提取率为指标,通过响应面试验优化UCWEPATPP的提取工艺条件。再使用扫描电镜(SEM)观察青稞提取过程中表面结构的变化,初步分析UCWEPATPP的提取机制。最后,使用高效凝胶排阻色谱仪对得到的青稞β-葡聚糖分子量范围进行测定。结果表明,最佳的UCWEPATPP工艺条件为酶添加量1.0%、超声时间9 min、超声功率140 W、硫酸铵添加量0.5 g/mL、三相提取温度35℃、三相提取时间1.5 h、料液比1:14 g/mL、叔丁醇与水相体积比1.3:1,酶解时间2.0 h。在此最优条件下,青稞β-葡聚糖提取率为66.96%±0.05%,青稞油提取率为81.42%±0.15%,青稞蛋白提取率为50.31%±0.23%。扫描电镜结果表明,UCWEPATPP使青稞表面组织结构变得通透、多孔。UCWEPATPP不仅能够同时提取青稞β-葡聚糖、青稞蛋白和青稞油,而且能够降低生产成本,提高青稞资源的利用率。该提取工艺的实际值与预测值拟合度较高,可用于预测青稞β-葡聚糖的提取,且得到的青稞β-葡聚糖分子量范围分布较为集中(1.7×10^(5)~3.0×10^(5)Da)。

Ultrasonic combined with enzymatic pretreatment-assisted three-phase partitioning(UCWEPATPP)was utilized to simultaneously extract theβ-glucan,protein and oil from highland barley(Hordeum vulgare L.var.nudum Hook.f.).Based on the single-factor experiments,the extraction process conditions of UCWEPATPP were optimized by response surface methodology(RSM)with the extraction rate of highland barleyβ-glucan as the index.Scanning electron microscope(SEM)was used to observe the change of surface structure during the extraction of highland barley,and the extraction mechanism of UCWEPATPP was preliminarily analyzed.Finally,the molecular weight range of the obtained highland barleyβ-glucan was determined using a high performance gel size exclusion chromatography.The results showed that the optimal UCWEPATPP process conditions were as follows:Enzyme addition was 1.0%,ultrasonic time was 9 min,ultrasonic power was 140 W,ammonium sulfate addition was 0.5 g/mL,three-phase extraction temperature was 35℃,three-phase extraction time was 1.5 h,the liquid ratio was 1:14 g/mL,the volume ratio of tert-butanol to aqueous phase was 1.3:1,the enzymatic hydrolysis time was 2.0 h.Under the optimal conditions,the extraction rate of highland barleyβ-glucan was 66.96%±0.05%,the extraction rate of highland barley oil was 81.42%±0.15%,and the extraction rate of highland barley protein was 50.31%±0.23%.Scanning electron microscope results showed that UCWEPATPP made the surface tissue structure of highland barley become transparent and porous.UCWEPATPP not only could extract highland barleyβ-glucan,protein and oil at the same time,but also could reduce the production cost and improve the utilization of highland barley resources.The actual value of the extraction process and the predicted value had a high degree of fit,which was used to predict the extraction of highland barleyβ-glucan.In addition,the obtained highland barleyβ-glucan had a relatively concentrated molecular weight distribution(1.7×10^(5)~3.0×10^(5)Da).