湿热处理对羟丙基淀粉结构特性及凝胶性能的影响

Effect of Heat-moisture Treatment on the Structure and Gel Properties of Hydroxypropyl Starch

羟丙基淀粉制备的水凝胶与普通淀粉相比具有更好的拉伸性,但凝胶的力学性能较差。本文主要探究湿热处理对羟丙基淀粉物理和化学性质及凝胶性能的影响。湿热处理后,羟丙基淀粉的热稳定性与对照相比有所提高,焓值从12.55J/g降低至6.58J/g;从X-射线多晶衍射图谱(XRD)分析看出,湿热处理使羟丙基淀粉的结晶度从30.4%降至19.6%,说明湿热造成羟丙基淀粉内部双螺旋的解旋,结晶被破坏;羟丙基淀粉的峰值粘度先上升到5 000 cP左右,后下降到3 000cP左右;质构仪(TPA)和流变分析发现,湿热处理后,羟丙基淀粉凝胶的硬度从223.51g增至463.50 g,提高了储能模量,表明湿热处理提高了凝胶的机械性能。

Hydrogels prepared by hydroxypropyl starch have better tensile properties than ordinary starch,but their mechanical properties are relatively poor.In this paper,effect of the heat-moisture treatment on the physical,chemical and the gel properties of hydroxypropyl starch was studied.Compared with the control group,the thermal stability of starch has been improved and the maintenance value decreased from 12.55 J/g to 6.58 J/g.The XRD analysis showed that the crystallicity of the strength from 30.4% to 19.6%.The double helix in strength was first destroyed by heat-moisture treatment.The peak viscosity of hydroxypropyl starch first rose to about 5 000 cp and then dropped to about 3 000 cp.The TPA and the rheological analysis showed that the hardness of the starch increased after the heat treatment of 223.51 g to 463.50 g and the storage elastic module increased,indicating that wet heat treatment improved the mechanical properties of the starch.