挤压处理对马铃薯全粉加工特性及微观结构的影响

采用挤压法对马铃薯全粉进行挤压处理，考察挤压温度、物料水分质量分数对马铃薯全粉加工特性及马铃 薯全粉面团弹性的影响，通过单因素试验确定最佳挤压工艺参数，采用扫描电子显微镜、差示扫描量热仪、快速黏 度测定仪、X射线衍射仪等仪器，对挤压处理前后马铃薯全粉的微观结构、热力学性质、糊化特性及结晶度变化等 进行对比分析。结果表明：当挤压温度为150 ℃、物料水分质量分数为35%时，马铃薯全粉的加工特性综合比较最 优，溶解度较高，持水性最好，冻融稳定性较好，此时马铃薯全粉面团弹性最好；挤压处理后的马铃薯全粉表面微 观结构出现褶皱，比表面积增加；热稳定性减弱，凝胶性减弱，不易回生；挤压处理使马铃薯全粉的结晶度下降。

Effect of Extrusion Treatment on Processing Characteristics and Microscopic Structure of Potato Flour

Potato flour was modified by extrusion cooking. The effects of extrusion temperature and water content on the processing characteristics of potato flour and dough elasticity were investigated. The optimum extrusion parameters were determined by one-factor-at-a-time method. Scanning electron microscopy, differential scanning calorimetry, a rapid viscosity analyzer and X-ray diffraction were used to evaluate the structure, thermodynamic properties, gelatinization characteristics and crystallinity of extruded and native potato flour. The results showed that an extrusion temperature of 150 ℃ and a water content of 35% were found to be the optimum conditions to obtain the best processing characteristics, higher solubility, the best water-holding capacity, better freeze-thaw stability and the highest dough elasticity. After extrusion, the surface microstructure of potato flour became wrinkled; the specific surface area increased, while the thermal stability, the gelation capacity and the crystallinity decreased. Extruded potato flour was difficult to retrograde.