湿热结合壳聚糖处理前后桄榔淀粉流变特性和热力学性质比较

Comparison of Rheological and Thermodynamic Properties of Arenga pinnata Starch before and after the Hygrothermal Treatment Combined with Chitosan

探讨湿热处理(Heat-Moisture Treatment,HMT)结合不同分子量的壳聚糖(Chitosan,CS)对桄榔淀粉(Arenga pinnata Starch,APS)流变性质和热力学特性的影响。动态流变分析结果表明,HMT结合CS处理提高了凝胶体系的粘弹性模量(G′和G′′),且随着CS分子量的增加,效果越明显,当添加10 ku CS时具有最高的粘弹性模量,G′为2899 Pa,G′′为309 Pa;HMT-APS-CS凝胶体系均表现为典型的非牛顿流体,呈现出类似固体的性质;损耗因子(tanδ)均小于1,且随着CS分子量的增加而损耗因子逐渐降低,HMT-APS-CS10具有最低的损耗因子,tanδ为0.09。静态流变分析结果表明,所有凝胶体系表现出剪切稀化现象,随CS分子量降低流体指数(n)显著降低。差示量热扫描(Differential Scanning Calorimetry,DSC)结果表明HMT结合CS处理,随CS分子量的提高,显著提高了APS的峰值温度(T_(P))(P<0.05),从69.42℃提高至86.68℃,显著降低了APS的糊化焓值(ΔH)(P<0.05),从3.47 J/g降低至1.07 J/g。HMT结合CS处理提高了APS凝胶结构和热力学稳定性,可为桄榔淀粉及其产品的开发利用提供一定的理论依据。

The influences of heat-moisture treatment(HMT)combined with chitosan(CS)of different molecular weights on the rheological and thermodynamic properties of Arenga Pinnata starch(APS)were investigated in this study.The results of dynamic rheological analysis showed that the combination of HMT and CS increased the viscoelastic moduli(G′and G′′)of the gel system,and the effect became more obvious with the increase of CS molecular weight.,When 10 ku CS was added,the viscoelastic moduli reached the highest(G′was 2899 Pa and G′′was 309 Pa);HMT-APS-CS behaved like typical non-Newtonian fluids,exhibiting solid-like properties;the loss factors(tanδ)of the APS-CS gel systems were all lower than 1,and decreased gradually with the increase of CS molecular weight,with HMT-APS-CS10 having the lowest loss factor(tanδwas 0.09).The results of static rheological analysis showed that all the gel systems exhibited shear thinning behaviours,and the fluid index(n)decreased significantly with the reduction of CS molecular weight.Differential scanning calorimetry(DSC)results showed that the HMT combined with CS treatment caused an increase in peak temperature(T_(P))(P<0.05)from 69.42℃to 86.68℃as the CS molecular weight increased,whilst decreased significantly the gelatinization enthalpy(ΔH)of APS(P<0.05)(from 3.47 J/g to 1.07 J/g.)The HMT combined with CS treatment improved the gel structure and thermodynamic stability of APS,which would provide certain theoretical basis for the development and utilization of APS and its products.