物理修饰对淀粉抗消化性能和分子结构的影响

Effect of Physical Modification on Structure and Digestion Resistibility of Starch

淀粉颗粒通过物理修饰,调节不同的水质量分数、温度、压力和处理时间,可以改变淀粉的抗消化性能。实验结果表明,压力和水质量分数对淀粉抗消化性能的影响显著(P<0.05),温度和时间这两个因素对淀粉的抗消化性能影响较小(P<0.05)。由正交实验结果可知,获得高抗消化淀粉质量分数的最佳处理条件为:温度120℃,压力9×105Pa,水质量分数为20%,处理时间1.5 h。经核磁共振、X射线衍射和差示扫描量热法对物理修饰后的淀粉分子结晶结构和热性能的分析发现,随着淀粉抗消化性能的提高,分子的有序化程度提高,但这些有序化的结构发生了由B型向V型的晶型转变。

The digestion resistibility of starch was changed by physical modification under different moisture mass percent, temperature, pressure and holding time. The results showed that the pressure and moisture mass percent had a significant effect （ P 〈 0. 05 ） of the starch digestion resistibility but the temperature and holding time had little effect （ P 〈 0.05 ）. From the results of orthogonal experiment, heating the starch granule at 120 ℃ and 9 × 10^5 Pa for 1.5 h with H2O mass fraction of 20% could formed the highest yield of resistant starch. Furthermore, the crystal structure and thermal behavior of starches after physical modification were investigated by NMR, XRD and DSC. It was found that the molecular reassociating and the ordering sequence of the starch granule could be greatly enhanced as the digestion resistibility increased with the physical modification and the crystalline structure changed from B -type to V- type polymorph.