魔芋葡甘聚糖对高酰基结冷胶晶态的影响

为了探讨天然高分子之间相互影响，本文研究了加热和微波两种不同处理方式下魔芋葡甘聚糖对高酰基结冷胶晶态及理化性质的影响。采用同步辐射X-射线纤维衍射分析晶态变化，流变仪分析了45 ℃和25 ℃下频率依赖性和5~80 ℃温度范围内的温度扫描，调制差式扫描量热分析法测定溶胶热稳定变化。发现魔芋葡甘聚糖导致高酰基结冷胶的晶格变小，但并未改变其斜方晶系晶体形状，晶格参数由a=14.6×10-10 m，b=16.8×10-10 m，c=21.2×10-10 m减小为a=13.2×10-10 m，b=13.7×10-10 m，c=17.5×10-10 m；魔芋葡甘聚糖使高酰基结冷胶的储能模量G'降低，损耗角tan(δ)升高，且二者对频率和温度的敏感性增强；加热和微波处理对理化性质的作用差别不大。结果表明，魔芋葡甘聚糖阻碍高酰基结冷胶螺旋分子的相互作用，魔芋葡甘聚糖不利于高酰基结冷胶凝胶网络及晶体结构的形成。
In order to explore the interaction between natural polymers, the effects of konjac glucomannan on the crystal structure and physicochemical properties of high acyl gellan gum, under heating and microwave treatments, were studied in this work. Changes in crystal structure were analyzed by synchrotron radiation X-ray fiber diffraction, the frequency dependences at 45 and 25 ℃ as well as the temperature sweep in the range of 5~80 ℃ were measured using a rheometer, and the change in thermal stability was measured using the modulated differential scanning calorimetric technique. The results showed that konjac glucomannan led to a diminished crystal lattice but its orthorhombic structure was unchanged. The lattice parameters a, b, and c were changed from 14.6 × 10-10 m, 16.8 × 10-10 m, and 21.2 × 10-10 m to 13.2 × 10-10 m, 13.7 × 10-10 m, and 17.5 × 10-10 m, respectively. Konjac glucomannan caused a decrease in the storage modulus G' and an increase in the loss angle tan (δ) of high acyl gellan gum; the sensitivities of G’ and δ to frequency and temperature were enhanced. No significant differences were found in the impacts of heating and microwave treatments on the physiochemical properties. The results suggested that the helical molecular interaction in high acyl gellan gum was hindered by konjac glucomannan, and konjac glucomannan did not facilitate the formation of high acyl gellan gum gel network and crystalline structure.