水分对高静压处理不同类型淀粉微观结构的影响

Effect of Moisture on High Hydrostatic Pressure Treated Waxy Maize Starch and Tapioca Starch

利用高静压(HHP)作为物理变性方法处理糯玉米淀粉和木薯淀粉,考察水分含量对不同类型淀粉的糊化及重结晶的影响。用偏光显微镜、扫描电子显微镜观测HHP处理后淀粉颗粒的形态变化,利用激光粒度分析仪记录淀粉颗粒的粒度分布及变化规律,结合X射线衍射曲线及低场核磁共振图谱,分析淀粉颗粒内水分的结合方式及程度。结果表明:当粉水比(淀粉质量和水质量之比)为3/10~5/10时,在HHP处理下,两种淀粉均发生结晶解体和溶胀现象。糯玉米淀粉的重结晶程度顺序为4/10粉水比】3/10粉水比】5/10粉水比;木薯淀粉颗粒结晶结构完全消失,结晶破坏的程度是3/10粉水比】4/10粉水比】5/10粉水比。随着水分含量增大,糯玉米淀粉及木薯淀粉的粒度逐渐增大。干燥后淀粉中的水分主要以结合水的形式存在,且水分参与结晶结构的形成。

Waxy maize and tapioca starch with different starch-water ratios were treated by high hydrostatic pressure(HHP)-aphysical modification method-under 600 MPa.The effects of moisture content on gelatinization and retrogradation properties of the two kinds of starch were investigated.The appearance and particle size of granules were studied by micro-polariscopy,scanning electron microscopy and laser diffraction instrument.Combining the X-ray diffraction and nuclear magnetic resonance(NMR)spectrum,the change from crystal to non-crystal was confirmed again,and the water status in starch was studied,too.The results indicate that the crystalline structure destroying and gelatinization happen when the starch-water ratio was between 3/10 and 5/10.The degree of retrogradation for waxy maize starch was 4/10>3/10>5/10(starch-water ratio),whereas the degree of crystalline structure destroying for tapioca starch was 3/10>4/10>5/10(starch-water ratio).The diameter of waxy maize and tapioca starch granules increased significantly with moisture content.Water was kept within the crystalline lamella in the form of bond water.