纤维对冰湖野米粉理化和消化特性的影响

Effects of fiber on physical and chemical properties and digestion characteristics of wild rice flour

中文关键词:  冰湖野米  纤维  理化特性  消化特性

英文关键词:wild rice  fiber  physicochemical properties  digestibility

中文摘要:

      目的 探究冰湖野米中内源纤维对冰湖野米粉的理化、功能和消化特性的影响。方法 以3种不同级的冰湖野米(长粒、中粒和短粒)和早籼米(对照)为原料, 将其研磨后过100目筛制备原米粉, 再采用焦亚硫酸钠法去除纤维制备去纤维米粉。利用扫描电镜和光学显微镜观察内源纤维对冰湖野米粉颗粒形貌的影响; 采用Brabender粘度仪测定内源纤维对冰湖野米粉的粘度特性的影响; 利用X射线衍射分析内源纤维对冰湖野米粉结晶特性的影响; 采用Englyst体外消化法评价内源纤维对冰湖野米粉消化性的影响。结果 不同颗粒长度的冰湖野米粉的形貌特征、结晶结构和粘度特性均无太大差异, 中粒冰湖野米粉慢消化淀粉含量最高, 短粒冰湖野米粉抗性淀粉含量最高。与早籼米相比, 冰湖野米粉起糊温度升高, 峰值粘度降低, 膨胀度降低, 快消化淀粉含量降低, 抗性淀粉含量升高。与原冰湖野米粉相比, 去除纤维后, 样品结晶度升高, 起糊温度降低, 峰值粘度升高, 膨胀度升高, 快消化淀粉含量升高, 抗性淀粉含量降低。结论 冰湖野米粉中内源纤维对冰湖野米粉粘度特性、结晶结构及消化性有显著的影响, 内源纤维的物理包埋以及与淀粉之间的相互作用, 会共同抑制淀粉颗粒的膨胀和糊化, 降低淀粉的消化酶解速率。

英文摘要:

      Objective To explore the effects of endogenous fibers in wild rice on the physicochemical, functional and digestive properties of wild rice flour. Methods Three different grades of glacial lake rice (long, medium and short) and early glutinous rice (control) were used as raw materials. The rice flour was prepared by grinding it through a 100 mesh sieve, and the fiber was removed by using sodium metabisulfite method to prepare defibrated rice flour. The effect of endogenous fiber on the particle morphology of glacial lake rice noodles was observed by scanning electron microscopy and optical microscopy. The effect of endogenous fiber on the viscosity characteristics of glacial lake rice flour was determined by Brabender viscometer. The endogenous fiber was analyzed by X-ray diffraction. The effect of endogenous fiber on the digestibility of glacial wild rice flour was evaluated by Englyst in vitro digestion. Results There was no significant difference in morphology, crystalline structure and pasting properties of wild rice flour with different grain lengths. The highest contents of slowly digestible starch and resistant starch were in medium grain and short grain wild rice flour, respectively. Compared with defibrated rice flour, wild rice flour displayed higher pasting temperature and resistant starch contents, and lower peak viscosity, swelling power and rapidly digestible starch contents. In comparison with wild rice flour, the defibrated wild rice flour showed higher crystalline degree, peak viscosity, swelling power and rapidly digestible starch contents, and lower pasting temperature and resistant starch contents. Conclusion The endogenous fiber in wild rice flour shows remarkable influence on the pasting property, crystal structure and digestibility of wild rice flour. The physical embedding of endogenous fibers and the interaction with starch will inhibit the expansion and gelatinization of starch granules and reduce the digestive rate of starch. These results can be due to physical embedding of the endogenous fiber and the interaction between the starch and fiber, which can inhibit starch swollen and gelatinization, and hence decrease enzyme hydrolysis rate of wild rice flour.