冰湖野米粉及其淀粉的精细结构、理化和消化特性研究

Study on the fine structure,physicochemical and digestive characteristics of Zizania palustris flour and its starch

目的 探究冰湖野米粉及其淀粉的理化性质、结构特性和消化特性的差异,同时揭示不同颗粒长度的冰湖野米淀粉的精细结构。方法 以3种不同颗粒长度的冰湖野米和1种早籼米(对照组)为原料,将其研磨过筛制备米粉样品,再用焦亚硫酸钠法和甲苯法进行纯化得到对应的淀粉样品。采用体积排阻色谱分析法与荧光辅助毛细管电泳法测定冰湖野米淀粉的精细结构(直链淀粉和支链淀粉的链长分布);利用扫描电镜、光学显微镜、X-射线衍射仪、傅里叶变换红外光谱仪和布拉班徳粘度仪等现代分析仪器对冰湖野米粉及其淀粉的理化性质和结构特性进行测定;采用Englyst体外消化法测定冰湖野米粉及其淀粉的体外消化特性。结果 不同颗粒长度的冰湖野米粉及其淀粉的颗粒形貌特征、结晶结构及直链淀粉含量无显著差异。与早籼米相比,冰湖野米粉及其淀粉的起糊温度高,峰值黏度低,相对结晶度低,热稳定性好,抗性淀粉含量高,主要归因于冰湖野米的支链淀粉结构及其较高的直链淀粉含量。与冰湖野米淀粉相比,冰湖野米粉颗粒更大,结晶度降低,膨胀度降低,慢消化性增加,主要归因于冰湖野米粉中较高的内源蛋白和纤维含量。结论 冰湖野米粉及其淀粉在颗粒形貌、结晶度、膨胀度和消化特性方面存在显著差异,冰湖野米中的内源纤维、蛋白质、直链淀粉含量及支链淀粉结构对其黏度特性、膨胀度、结构特性及消化特性有显著的影响。

Objective To explore the differences in physicochemical properties,structural characteristics and digestive properties of Zizania palustris flour and its starch,and reveal the fine structures of Zizania palustris starch with different grain lengths.Methods Three kinds of Zizania palustris with different grain lengths and 1 early indica rice(control group) were used as raw materials to prepare rice flour samples by grinding and screening.Then the rice flour was purified by sodium pyrosulfite method and toluene method to obtain the corresponding starch samples.The fine structure of Zizania palustris starch(chain length distribution of amylose and amylopectin) was determined by size exclusion chromatography and fluorescence assisted capillary electrophoresis.The physicochemical properties and structural characteristics of Zizania palustris flour and its starch were determined by scanning electron microscope,optical microscope,X-ray diffractometer,Fourier transform infrared spectrometer and Brabender viscometer.In vitro digestive properties of Zizania palustris flour and its starch was determined by Englyst digestion method.Results The results showed that there were no significant differences in particle morphology,crystalline structure and amylose content between Zizania palustris flour and its starch with different grain lengths.Compared with early indica rice,Zizania palustris flour and its starch had higher gelatinization temperature,lower peak viscosity,lower relative crystallinity,better thermal stability,and higher content of resistant-starch,which were mainly attributed to the amylopectin structure and higher amylose content of Zizania palustris.Compared with Zizania palustris starch,Zizania palustris flour had larger particle size,lower crystallinity,lower swelling capacity,and increased slowly digestive rate,which was mainly attributed to the high content of endogenous protein and fiber in Zizania palustris.Conclusion Zizania palustris flour and its starch differs significantly in particle morphology,crystallinity,swelling capacity and digestive characteristics.The endogenous fiber,protein,amylose content and amylopectin structure in Zizania palustris has significant effects on the viscosity properties,swelling capacity,structural characteristics and digestive properties of Zizania palustris.