明胶吸附单宁酸的机理探讨及其在蓝莓汁脱涩中的应用

Mechanism of Adsorption of Tannic Acid by Gelatin and Its Application to Astringency Removal of Blueberry Juice

分别用0.01~0.11 g的明胶吸附25 m L 900 mg/L单宁酸模拟溶液,根据明胶吸附量和单宁酸去除率得到明胶的最佳用量,然后研究最佳用量的明胶对25 m L 900 mg/L单宁酸模拟溶液的吸附动力学方程和吸附等温线方程,最后研究明胶对单宁酸质量浓度为900 mg/L的25 m L蓝莓汁的脱涩效果。结果表明:吸附25 m L 900 mg/L单宁酸模拟溶液时,明胶最佳用量为0.03 g,其明胶吸附量为527.5 mg/g,单宁酸去除率为70.33%。明胶吸附单宁酸的过程符合准二级动力学方程,其吸附等温线符合Langmuir吸附方程,为单分子层吸附。当脱除单宁酸含量为900 mg/L的25 m L蓝莓汁的涩味时,明胶用量0.03 g、温度15℃、振荡时间20 min,在该条件下,其明胶吸附量为420.8 mg/g,单宁酸去除率为56.11%,脱涩效果良好。

In order to investigate the effect of gelatin dosage on the adsorption of tannic acid, 0.01–0.11 g of gelatin was used to adsorb 25 m L of 900 mg/L tannic acid model solution. The gelatin dosage was optimized for the adsorption capacity of gelatin and the removal rate of tannic acid. The adsorption kinetics and adsorption isotherms of tannic acid by gelatin were explored as well. In addition, the effect of gelatin adsorption on blueberry juice astringency was examined. The results showed the optimal gelatin dosage was 0.03 g, leading to an adsorption capacity of 527.5 mg/g and a removal rate of tannic acid of 70.33%. The adsorption of tannic acid by gelatin was described by pseudo-second order adsorption kinetics; the adsorption isotherm was described by Langmuir adsorption model and it was monolayer adsorption. When 25 m L of blueberry juice containing 900 mg/L tannic acid was shaken at 15 ℃ for 20 min after addition of 3 g of gelatin, the adsorption capacity was 420.8 mg/g and the removal rate of tannic acid was 56.11%.