超微粉碎处理对木薯淀粉结构及消化特性的影响

为研究超微粉碎改性木薯淀粉及其对消化性的影响,以粒度分析、扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶红外分析(FT-IR)以及Englyst法为分析手段,研究木薯淀粉经过不同时间(0、15、30、45、60 min)超微粉碎处理后的粒度、微观结构及消化特性的变化。结果表明:木薯淀粉经超微粉碎处理60 min后,颗粒结构被严重破坏,淀粉颗粒之间发生团聚,淀粉粒径由13.50 μm增加至36.17 μm;超微粉碎处理对木薯淀粉的晶型没有影响,仍为A型,但其相对结晶度由21.33%下降至1.14%;木薯淀粉在3000~2800 cm^-1与1080 cm^-1处的吸收峰强度减弱,表明超微粉碎处理使木薯淀粉的结构遭到破坏,氢键相互作用减弱;天然木薯淀粉的快消化淀粉(RDS)、慢消化淀粉(SDS)、抗性淀粉(RS)的含量分别为3.91%、44.71%、51.38%,经过超微粉碎处理60 min以后,RDS与SDS的含量分别增加至6.87%和45.91%,RS的含量下降至47.21%,说明超微粉碎处理能够在一定程度上改变木薯淀粉的消化性。

Effect of Micronization on the Structure and Digestibility of Tapioca Starch

The granular size,microstructure and digestibility of micronized tapioca starch with different time(0,15,30,45,60 min)were investigated by particle size analysis,scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and Englyst method,which can provide a theoretical basis for the research of micronization modified tapioca starch and its effect on digestibility. The results showed that the granular structure of starch was seriously damaged,and the starch granules agglomerated after the micronization treatment. When the time of micronization reaches 60 min,the particle size of starch increased from 13.50 μm to 36.17 μm and the A-type crystal structure was not changed,while the degree of crystallinity decreased from 21.33% to 1.14%. The intensities of the infrared(IR)absorption peaks at 3000~2800 cm-1 and 1080 cm-1 was decreased,indicating that the structure of tapioca starch was destroyed by micronization treatment,and the hydrogen bond interaction was weakened. The content of rapidly digestible starch(RDS),slowly digestible starch(SDS),and resistant starch(RS)in the native tapioca starch were 3.91%,44.71%,and 51.38%,respectively. After 60 min of micronization treatment,the contents of RDS and SDS increased to 6.87% and 45.91%,respectively,while the content of RS decreased to 47.21%,showing that micronization treatment could slightly change the digestibility of tapioca starch.