吸附降氟法制备低氟边茶膏的效果评价

Equilibrium and Kinetic Studies and Process Optimization of Fluorid Adsorption from Traditional Tibetan Bian Tea Infusion

从11种材料中选择对茶汤中氟具有较强吸附性能的食用级磷酸三钙和阴离子树脂,研究二者的吸附性能。采用高氟边茶为原料,研究磷酸三钙吸附降氟的工艺参数,并对制成的低氟边茶膏品质进行感官评价。结果表明:磷酸三钙在高温下具有较强的吸附性能,其饱和吸附量高达10.63mg/g以上;进一步采用磷酸三钙对茶汤吸附降氟的工艺进行优化,其茶汤吸附降氟的最佳工艺参数为茶汤温度100℃、磷酸三钙用量0.7g/100mL、吸附处理时间20min,在该工艺组合下,茶汤中氟的去除率达到95.80%;将吸附降氟后的茶汤浓缩制备低氟边茶膏,结果氟含量较对照低94.80%,茶膏含氟量为66.52mg/kg;经稀释后具有汤色红浓明亮、陈香浓郁、滋味醇和的品质特征。

In the present study,food-grade tertiary calcium phosphate（TCP）and 731 type anion exchange resin were selected out of 11 kinds of adsorbents as better ones towards fluoride in the infusion of traditional Tibetan Bian tea.To prepare low-fluoride Bian tea cream,equilibrium and kinetic studies of fluoride from Bian tea infusion with a fluoride of 7.18 mg/L were made,and the technological conditions of TCP adsorption for reducing fluoride were optimized by orthogonal array design method.Meanwhile,the Bian tea cream prepared based on optimized fluoride reduction process was evaluated for its sensory quality.TCP was found to have stronger ability to adsorb fluoride at high temperature,with a saturated adsorption quantity of over 10.63 mg/g.The best process parameters for TCP adsorption towards fluoride were as follows：tea infusion temperature 100℃;TCP loading 0.7 g/100 mL;and adsorption time 20 min,and the resulting removal rate of fluoride from Bian tea infusion was up to 95.80%.After the reduction of fluoride,concentration was done to obtain a low-fluoride tea cream.The product exhibited a fluoride content of 66.52 mg/kg,94.80%lower than that of the control（directly concentrated without fluoride reduction）,and its redilution had the characteristics of brilliant red color,strong stale flavor,and pure and mild taste.