冻融和盐作用对糯米粉的结构和糊化特性的影响

The effect of freeze thawing and salt action on the structure and gelatinization of sticky rice flour

糯米浆是我国古代应用最广泛的建筑胶凝材料,可显著提高三合土和灰浆的强度特性、抗渗特性和粘结特性.挖掘糯米浆的科学价值,对于传统技术的科学利用,特别是对古建筑的修复具有十分重要的意义.文中用石油醚对糯米粉进行脱脂,采用双波长法对糯米粉中的直链淀粉和支链淀粉进行测定,用FT-IR,XRD,TG/DTG和SEM分析了糯米粉脱脂前后的结构和形貌,同时用XRD和SEM分析了冻融循环、Na 2SO 4加入对糯米淀粉结构、晶型和形貌的改变,用Brabender粘度仪研究了不同条件下的糊化特性.结果表明,糯米粉中直链淀粉和支链淀粉的含量分别为9.16%和78.56%,糯米粉和脱脂糯米粉的糊化温度基本相同,但峰值粘度、崩解值和回升值下降.冻融循环不会改变糯米粉中淀粉颗粒的结构和晶型,但峰值粘度、谷值粘度、终值粘度、崩解值和回升值均有降低趋势;加入4%的Na 2SO 4后,会使糊化温度升高,崩解值升高,回升值下降.本研究对糯米粉的科学认知具有重要的意义,期望为针对性地提高糯米浆的胶凝品质提供理论参考.

The sticky rice paste is the most widely used building material in ancient China that can greatly improve the strength,anti-permeability and bonding characteristics of cement and mortar.Excavating the scientific value of sticky rice in the mortar is the need for the scientific use of traditional technology,in particular with the significance of the restoration of ancient buildings.In the paper,the sticky rice flour was degreased with petroleum ether,and amylose and amylopectin were tested by dual-wavelength method.FT-IR,XRD,TG/DTG and SEM were used to analyze the structure and morphology of glutinous rice flour before and after degreasing.XRD and SEM were adopted to analyze freeze-thaw cycle and the changes of the structure,crystal form and morphology of sticky rice starch added with Na 2SO 4.What s more,the viscometer Brabender was made to study the gelatinization characteristics under different conditions.The results showed that the contents of amylose and amylopectin in glutinous rice flour are 9.16%and 78.56%,respectively.The gelatinization temperature of glutinous rice flour and degreased glutinous rice flour are basically the same,but the peak viscosity,disintegration value and rebound value are decreased.The freeze-thaw cycle can not change the structure and crystal form of starch particles in sticky rice flour,but the peak viscosity,bottom viscosity,final viscosity,disintegration value and rebound value tend to decrease.When adding to 4%Na 2SO 4,the gelatinization temperature and disintegration value are increased,while the rebound value are decreased.This study has important significance for the scientific understanding of sticky rice flour,and is expected to provide a theoretical reference for being targeted to improving the binding quality of sticky rice paste.