干燥方法对山药粉性质的影响

通过真空干燥、冷冻真空干燥和喷雾干燥制备山药生/熟粉,研究其流变特性、糊化特性和消化性质,初步探究其变化机制。结果表明,山药生粉具有较高的成糊温度,山药熟粉中冷冻真空干燥山药熟粉的峰值黏度最高(3619.50 cP)。不同干燥方法干燥的山药粉均呈非牛顿流体特性,冷冻真空干燥的山药熟粉的粘弹性最高;山药生粉呈现完整的淀粉颗粒形态,山药熟粉的颗粒形貌差异较大。熟化处理使山药粉抗性淀粉含量显著降低(P<0.05)。熟粉中真空干燥山药熟粉的抗性淀粉含量最高(56.11%)。三种干燥方法中,冷冻真空干燥能较好的保留山药粉的原有理化特性。

Effects of Drying Methods on Properties of Yam Flours

The raw/cooked yam flours were prepared by vacuum drying,freeze vacuum drying and spray drying to study their rheological properties,gelatinization properties and digestion properties,and to explore the mechanism of properties change.The results showed that raw yam flour reflected a higher paste temperature,and the freeze-dried cooked yam flour had higher peak viscosity( 3619.50 cP).The yam flours dried by different drying methods showed non-Newtonian fluid characteristics,and the viscoelasticity of frozen cooked yam flour was the highest.The raw yam flour showed a complete shape of starch granules,and the granule morphology of cooked yam flour varied greatly.The ripening treatment significantly reduced the contents of resistant starch in yam flour.The vacuum-dried cooked yam flour had the highest resistant starch content( 56.11%). Among the three drying methods,freeze vacuum drying better retained the native physicochemical properties of yam flour.