挤压处理对青稞粉质构性质及消化性的影响

Evaluation of Extrusion Process on Texture Properties and Digestibility of Barley Meal

挤压处理对青稞粉的质构性质如糊化、微观结构和宏观性质具有重要影响。研究挤压处理对青稞粉的糊化度、膨胀率、水溶性指数(water solubility index,WSI)、吸水指数(water absorption index,WAI)、质构性质及消化性的影响。结果表明:物料含水量为13%,机筒温度为160℃(最高),螺杆转速为150r/min的条件下,糊化度达到94.50%。扫描电镜观察显示挤压青稞粉从原始紧密包裹的质地变为海绵状多孔形态;挤压青稞粉的糊化温度(50.50℃)低于未挤压过的青稞粉(66.85℃);快速黏度分析(rapid viscosity analysis,RVA)显示挤压后的青稞粉变得更稳定并且更容易糊化,这与体外消化试验一致。

The texture properties of barley powder, such as gelatinization, microstructure and macroscopic properties, were greatly affected by extrusion. This work focused on evaluation of gelatinization degree, expansion ratio, water solubility index (WSI), water absorption index (WAI), texture properties and digestibility of barley meal before and after extrusion. Results indicated that under the conditions of 13 % moisture content, 160 ℃ barrel temperature and 150 r/min screw speed, gelatinization degree of barley meal could achieve 94.5 %. The scanning electron micrograph (SEM) result indicated that the microstructure of extruded barley meal changed from the original tightly wrapped texture to spongy and porous structure. The gelatinization temperature (50.50 ℃) of barley meal with extrusion was lower than those without extrusion (66.85 ℃). Rapid viscosity analysis (RVA) showed that extruded barley meal became more stable and easier to be gelatinized, which was consistent to the in vitro digestion experiment.