魔芋葡甘聚糖与琼脂共混溶胶的剪切流变特性研究
Study on shear rheological properties of Konjac glucomannan and Agar blends
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摘要: 利用流变仪研究了不同质量浓度、溶胀时间和温度条件下魔芋葡甘聚糖/琼脂(KGM/Agar)共混体系的剪切流变特性。结果表明:KGM/Agar共混体系随着质量浓度增大,黏稠系数k增大;随着加热时间延长,黏稠系数k增大;而温度在30~60℃范围内,黏稠系数k随着温度升高先增大再减小然后再增大,呈现波浪式。从黏稠系数和流动指数结果表明,其混合胶的最佳工艺为:KGM/Agar共混胶的质量浓度1.2%,溶胀温度40℃,溶胀时间120 min。魔芋葡甘聚糖/琼脂(KGM/Agar)共混体系流变特性服从幂律方程,通过进一步对黏稠系数k和流动指数n随浓度、时间和温度的变化趋势进行拟合,其关系曲线分别用指数函数和多项式曲线拟合,以期为KGM/Agar的应用和质量评价提供指导。Abstract: Rheometer was used to determine rheological properties of Konjac glucomannan and Agar ( KGM/Agar) under various conditions of concentration, heating time and temperature. The results showed that the viscous coefficient ( k) of KGM/Agar blend system increased with the the increase concentration and the heating time prolong.While the temperature was in the range of 30 ~ 60 ℃, the viscous coefficient ( k) increased at first then decreased and increased again as wave-like changes, with increasing temperature. The results of viscosity coefficient and flow index showed that the optimal parameters was the mass concentration of KGM/Agar blend 1.2%, swelling temperature of 40 ℃, swelling time 120 min. The rheological properties of KGM/Agar blend system could be fitted by power-law model and the change tendencies of viscosity factor ( k) and flow index ( n) correlated with concentration, heating time and temperature were also obtained.The curves could be fitted by power and polynomial curve and could provide a reliable foundation for proper applications of KGM/Agar in the food industry and its quality evaluation.