糯米粉制备工艺对其淀粉损伤和品质特性的影响

EFFECTS OF MILLING PROCESS ON THE STARCH DAMAGE AND QUALITY OF GLUTINOUS RICE FLOUR

糯米粉在加工制备过程中,不可避免地会产生破损淀粉,从而影响糯米粉的加工品质。以破损淀粉含量为评价指标,对糯米粉的3种加工工艺进行优化,并对3种工艺制得的糯米粉的粒度、微观结构、破损淀粉含量、理化特性、糊化特性、质构特性进行比较分析。优先得到3种工艺最优工艺参数:干法为水分含量16.5%、药物粉碎机、粒度80目;半干法为浸泡时间143 min、浸泡温度51.8℃、干燥温度85℃;湿法为蒸馏水、浸泡温度35℃、浸泡时间90 min、过磨1次、干燥温度40℃。比较发现,半干法和湿法加工制得的粉质细腻,色泽好;干法糯米粉颗粒形状不规则,表面粗糙。干法样品破损淀粉含量最高,为9.31%;湿法样品破损淀粉含量最低,仅为5.03%;半干法粉糊保水力最大,可达11.1%,析水率最低,为75.53%,冻融稳定性最好。干法样品的峰值黏度、低谷黏度、衰减值、最终黏度均最低,半干法样品的峰值黏度、低谷黏度、衰减值、最终黏度最高,回生值最低。半干法制粉可以改善糯米粉的粉质特性,使其更接近于湿法糯米粉。

Glutinous rice flour will inevitably produce damaged starch in the process of milling,which will affect the processing quality of glutinous rice flour.Three kinds of processing techniques of glutinous rice flour were optimized with the damaged starch content as the evaluation index.The pewticle size,microstructure,damaged starch content,physical and chemical properties,gelatinization properties and texture characteristics of glutinous rice flour prepared by the three processing methods were also compared and analyzed.The results showed that the optimum technological parameters of the three methods were as follows:for the dry milling method,the moisture content of 16.5%and the particle size of 80 mesh;for the semi-dry milling,soaking time of 143 min,soaking temperature of 51.8℃and drying temperature of 85℃;for the wet milling,distilled water soaking temperature of 35℃,soaking time of 90 min,grinding one time and drying temperature of 40℃.Comparison of the three processing methods,it was founded that the glutinous rice flour made by semi-dry and wet milling methods had fine particle size and good color,while the glutinous rice flour prepared by dry milling methods had irregular particles shape and rough surface.The damaged starch content of dry milling flour was highest and up to9.31%,while that of the wet milling flour was only 5.03%.The maximum water holding capacity of semi-dry milling powder paste was up to 11.1%,the lowest water bleeding ratio was 75.53%,and the freeze-thaw stability was the best.The peak viscosity,trough viscosity,breakdown and final viscosity of glutinous rice flour treated by dry milling method were the lowest,but those of glutinous rice flour prepared by semi-dry milling were the highest,except for the final viscosity was the lowest.Semi-dry milling will improve the flour characteristics of glutinous rice flour,and the quality of the afforded flour was more close to the quality of the wet milling glutinous rice flour.