单螺杆挤压对苹果渣中水溶性膳食纤维的影响

利用挤压膨化技术对苹果渣进行预处理,研究挤压对苹果渣水溶性膳食纤维含量、物理结构的影响,优选出最佳的苹果渣挤压工艺参数。采用响应面法对物料含水量、螺杆转速、套筒温度3个因素进行优化,通过粒径分析、扫描电子显微镜(scanning electron microscope,SEM)表征挤压膨化处理前后苹果渣物理结构的变化。结果表明:物料含水量26%,螺杆转速160 r/min,套筒温度110℃为最佳挤压工艺,在此条件下测得的挤压苹果渣的水溶性膳食纤维含量为8.64%,比未挤压提高98.17%。粒径分布图直观显示出挤压苹果渣粒径比苹果渣细,均匀度更好;SEM图像对比说明经过挤压处理,苹果渣呈现出多孔隙及疏松的结构。

Effects of Single-screw Extrusion on Soluble Dietary Fiber in Apple Pomace

Apple pomace was pretreated by extrusion technology,and the effects of extrusion on the content of soluble dietary fiber,physical structure were studied optimizing the optimum extrusion process parameters for apple pomace.The response surface method was used to optimize the three factors of water content,screw speed,and sleeve temperature.The changes of physical structure of apple pomace before and after extrusion were characterized by particle size analysis,scanning electron microscope(SEM).The test results showed that the optimal extrusion process was water content of 26%,screw speed of 160 r/min,and sleeve temperature of 110℃.The content of soluble dietary fiber in extruded apple pomace was 8.64%under these extrusion conditions,which was increased by 98.17%compared with apple pomace.The particle size distribution showed that the particle size of extruded apple pomace was smaller than that of apple pomace and the uniformity was better.The comparison of SEM images showed that the surface of apple pomace was porous and the fiber became loose after extrusion.