有机五色小米淀粉的精细结构、理化性质和消化性研究

Study on fine structure, physicochemical and digestive properties of organic 5-color millet starch

中文关键词:  有机五色小米淀粉  消化性  精细结构  糊化特性  粘度特性

英文关键词:organic 5-color millet starch  digestibility  fine structure  gelatinization characteristic  pasting property

中文摘要:

      目的 探究有机五色小米淀粉的精细结构、理化性质和消化性特性。方法 从红谷小米、绿小米、白小米、金苗小米和黑小米中分离纯化得到相对应的淀粉样品。利用体积排阻色谱法(size exclusion chromatography, SEC)与荧光辅助毛细管电泳法(fluorescence assisted capillary electrophoresis, FACE)测定5种有机小米的直链淀粉含量和支链淀粉的链长分布; 利用扫描电镜、差示扫描量热仪、X-射线衍射仪、小角射线散射分析和布拉班徳黏度仪等对有机五色小米淀粉的形貌特征、结晶结构、功能特性进行测定; 利用斜率对数法测定有机五色小米淀粉的消化特性。结果 体外斜率对数法消化性结果表明, 有机五色小米淀粉的最终消化率(C120)差别并不明显, 其中黑小米淀粉的C120最低(72.23%±4.97%), 金苗小米淀粉的C120最高(78.15%±0.40%), 其次依次为白小米>绿小米>红谷小米。有机绿小米淀粉最易糊化, 与自身支链淀粉的短链分布有关。有机黑小米淀粉糊化峰值温度最高, 金苗小米次之, 与其结晶度及直链淀粉含量有关。黑小米淀粉的峰值黏度最低, 最难糊化, 与支链淀粉的平均链长较长难断裂有关。有机五色小米淀粉结晶度整体差异不大, 半结晶结构中红谷小米的松散程度最大。结论 有机五色小米淀粉在颗粒形貌、结晶度、直链淀粉含量和消化特性方面差异小, 但小米淀粉的直链淀粉含量和支链淀粉结构对其黏度、糊化、结构和消化特性有显著的影响。

英文摘要:

      Objective To investigate the fine structure, physicochemical properties and digestive characteristics of organic 5-color millet starch. Methods The corresponding starch samples were isolated and purified from red grain millet, green millet, white millet, golden seedling millet and black millet. The content of straight-chain amylose and the chain length distribution of branched-chain amylose in the 5 kinds of organic millet were determined by the size exclusion chromatography (SEC) and fluorescence assisted capillary electrophoresis (FACE). The morphological characteristics, crystalline structure and functional properties of the organic 5-color millet starch starches were determined by scanning electron microscopy, differential scanning calorimetry, X-ray diffractometry, small-angle ray scattering analysis and Brabender viscometer, etc. The digestive properties of the organic 5-color millet starch were determined by the slope logarithm method. Results According to in vitro digestibility by log of slop, the estimated amount of starch hydrolyzed at the reaction end point (C120) of organic 5-color millet starch was not significantly different, among which the C120 of black millet starch was the lowest (72.23%±4.97%), and the C120 of golden millet starch the highest (78.15%±0.40%), then followed by white millet>green millet>red millet. Green millet starch was the easiest to gelatinize and was related to its short chain distribution of amylopectin. The peak temperature of black millet starch was the highest, followed by gold millet starch, which was related to its crystallinity and amylose content. The black millet starch displayed the lowest peak viscosity, and showed the hardest gelatinization characteristic, which was related to the longer average chain length of amylopectin that was difficult to break. The crystallinity of organic 5-color millet starch showed little difference, and the largest loose degree in semi-crystalline structure of red millet starch was observed. Conclusion The differences of organic 5-color millet starch in granule morphology, crystallinity, straight-chain amylose content and digestive properties are small, but the straight-chain amylose content and branched-chain amylose structure of millet starch have significant effect on its viscosity, pasting, structure and digestive properties.