马铃薯抗性淀粉结构特征及体外消化特性的研究

Researched on structural characteristics and in vitro digestibility of potato resistant starch

中文关键词:  马铃薯抗性淀粉  结构特征  体外消化性

英文关键词:potato resistant starch  structural characteristics  in vitro digestibility

中文摘要:

      目的 研究马铃薯抗性淀粉的结构特征与体外消化特性。方法 以马铃薯淀粉为对照, 采用红外光谱仪、X射线衍射仪技术(X-ray diffraction, XRD)、差示扫描量热法(differential scanning calorimetry, DSC)等手段研究马铃薯抗性淀粉的碘吸收特性、颗粒形貌、晶型结构形态、热特性。通过模拟体外消化评价马铃薯抗性淀粉的消化性能。结果 马铃薯淀粉和抗性淀粉碘吸收曲线最大吸收峰均在580~600 nm, 马铃薯抗性淀粉分子量分布更集中。马铃薯淀粉为B型结晶结构, 马铃薯抗性淀粉为C型结晶结构。扫描电子显微镜(scanning electron microscope, SEM)观察显示, 马铃薯淀粉分子颗粒完整, 表面光滑, 整体呈不规则的椭圆形; 马铃薯抗性淀粉分子为不规则多面体, 分子表面粗糙、有凹陷, 且有少量的层状起伏; 红外光谱分析表明抗性淀粉未出现新的基团。DSC检测发现, 马铃薯抗性淀粉的热稳定性更高; 马铃薯淀粉和抗性淀粉酶解前2 h内消化速率迅速增加, 酶解2 h后速率减慢, 消化速率逐渐趋于平缓, 血糖指数分别为70.42、40.50。结论 马铃薯抗性淀粉具有较致密的结晶结构和较强的酶抗性, 抗消化性显著。

英文摘要:

      Objective To study the structure and in vitro digestibility of potato resistant starch. Methods Compared with potato starch, the iodine absorption characteristics, particle morphology, crystal structure and thermal properties of potato resistant starch were studied by infrared spectroscopy, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The digestibility of potato resistant starch was evaluated by simulated in vitro digestion. Results The maximum absorption peaks of iodine absorption curve of potato starch and potato resistant starch were all 580-600 nm, and the molecular weight distribution of potato resistant starch was more concentrated. Potato starch was B-type crystal structure, and potato resistant starch was C-type crystal structure. Scanning electron microscope (SEM) observation showed that potato starch molecular particles were complete, smooth and irregular oval; The molecular surface of potato resistant starch was rough, concave and a little undulating; infrared spectroscopy analysis showed that there was no new group in potato resistant starch. DSC results showed that the thermal stability of potato resistant starch was higher; the digestibility rate of potato starch and potato resistant starch increased rapidly within 2 h before enzymatic hydrolysis, and slowed down after 2 h. The digestibility rate tended to be flat, and the glycemic indexes were 70.42 and 40.50, respectively. Conclusion Potato resistant starch has dense crystal structure, strong enzyme resistance, and has significant digestibility resistance.