钠离子对高酰基结冷胶流变特性及其悬浮稳定性的影响

The Effect of Sodium Ion on Rheological Properties of High Acyl Gellan Gum and Stabilization of Blueberry Juice

高酰基结冷胶作为一种新型稳定剂,在果汁饮料尤其是浊汁饮料中具有优势。为研究钠离子强度对高酰基结冷胶流变及悬浮稳定性能的影响,比较不同钠离子强度下高酰基结冷胶表观黏度、剪切应力的变化,并将其应用于蓝莓浊汁中,分析离子强度对体系悬浮稳定性能的影响。结果表明:对于高酰基结冷胶溶液(0.10 g/100 m L),钠离子添加量在0~0.20%时,其表观黏度呈现先增大后减小的趋势。钠离子添加量为0.15%时,其表观黏度由原来的0.0110 m Pa·s上升到0.1303 m Pa·s,流体假塑特性也随之增强。Casson和Power-Law方程均能较好拟合其流变行为(R^2>0.99)。针对以高酰基结冷胶为稳定剂的蓝莓汁体系,钠离子的添加并未改变其粒径分布(P>0.05),而在钠离子添加量0~0.15%范围内,钠离子的添加降低了体系的稳定参数和动态变化值,即体系的悬浮稳定性提高。当钠离子添加量超过0.20%时体系失稳。对于以高酰基结冷胶为稳定剂的蓝莓汁体系,钠离子添加量在0.15%时其悬浮稳定性能最佳。

The influence of sodium ion on rheological properties of high acyl （HA） gellan gum and stabilization of blueberry juice were investigated.The addition of sodium ion increased the apparent viscosity and flow indexes （n〈1） of HA gellan gum.Two mathematical models including Power-Law and Casson equations were compared and discussed.The results showed that the Power-Law model provided the best correlation capacity with the decision coefficient R2 of 0.999.Then different concentration of sodium ions mixed with HA gellan were separately added into blueberry juice to see the effect of sodium ion.The particle size distributions,turbidity,viscosity,stability index and sedimentation of each sample was evaluated.The samples of higher concentration of sodium ion had higher turbidity,viscosity and lower sediment.The HA gellan gum with 0.15% sodium ion had a great influence on stabilization of blueberry juice.