茶叶中铝的卫生学实验研究

Experimental Studies on the Hygienics of Aluminum in Tea

目的 了解茶叶中铝含量。方法 应用电感耦合等离子体发射光谱 (ICP OES)法 ,测定市售 10种不同品种中国茶叶中的铝含量。结果 其范围在 339～ 1745mg/kg之间。测定各种茶叶沸水浸出液中铝的溶出率 ,总溶出量的 80 %～90 %在第 1次浸泡中被溶出。实验证实茶水中铝主要以无机形态存在。茶水中无机氟浓度与铝浓度的摩尔比 (F/Al)在0 7～ 1 2之间 ,按化学平衡方程计算 ,95 %～ 99%的铝是以低毒的AlF2 +络合态存在。根据实验所得数据计算每日饮茶 1次铝的摄入量 ,其值分别为FAO/WHO提出的每周允许摄入量 (PTWI) 7mg/kg的 1/ 140～ 1/ 17,为文献建议的我国成人铝每日允许摄入量 40mg/日的 1/ 184～ 1/ 11。 结论 茶叶中铝含量虽然为各类天然食物中铝含量最高者 ,但由于溶出率较低 ,6 0 %～ 80 %为不可利用铝。

Objective To konw the aluminum content in Chinese teas.Method Aluminum content in the different Chinese teas was measured by inductivity coupled plasma opticald emission spectrometry(ICP OES).Results The content of aluminum was within limits of 339～1745 mg/kg in tea samples.Also measured the percent of extraction of aluminum of various kind tea leaves infusion,about 80%～90% aluminum of total extraction rate was in the first infusion of tea.Experiments have been proved aluminum in tea infusions mainly exists in inorganic species.The mole ration of fluoride to aluminum in tea infusion was 0 7～1 2,Calculated according to the equilibrium equation of Al 3+ +F -=AlF 2+ (K=10 6 13 ),95%～99% aluminum is complex compound species as ALF 2+ in the infusion.It was calculated that drinking 5g tea infusions daily may supply aluminum about 1/140～1/17 of the provisional tolerable weekly intake(PTWI)dose set by the joint FAO/WHO Expert Committee.Conclusion On the other hand,the species of AlF 2+ in tea infusion is a lower toxicity compound.For these reasons,the hygienic estimation of aluminum in teas is not a dangerous factor for the human health.