茶叶中稀土元素的研究进展

Research progress of rare earth element in tea plants (Camelliasinensis L.)

中文关键词:  茶叶  稀土元素  限量  日摄入量

英文关键词:tea  rare earth element  limit  daily dietary intake

中文摘要:

      稀土元素对茶树生长和茶叶品质有系列影响。茶树对轻稀土(La, Ce, Y和Nd等)具有较强的生物富集作用, 茶树各部位稀土总量大小为: 根＞茎＞老叶＞成熟叶＞叶柄＞芽头, 其中茶树叶片中的稀土含量与其老嫩度呈显著的正相关。据报道, 我国居民膳食摄入稀土含量均值为0.133 mg/d, 而通过饮茶摄入稀土的含量估算为0~0.1129 mg/d, 均远小于文献报道的稀土日允许摄入量(1.2~57.6 mg/d), 稀土元素饮食暴露水平很低。目前, 还没有稀土日允许摄入量的相关标准, 但茶叶中稀土总量限量标准和粮食作物一样(2 mg/kg), 茶叶不同于粮食作物, 在限量的相关标准制订中应充分考虑茶叶的日消费量及稀土元素的水溶性。建议加强稀土食品安全的基础研究和系统性风险评估, 以便为完善食品(茶叶)中稀土限量标准提供科学依据。

英文摘要:

      Rare earth element can be both a help and a hindrance for tea plants growth and tea quality. Tea plant had an enrichment impact on light rare earth element (La, Ce, Y and Nd, etc.), and the rare earth oxides (RE2O3) content of tea plant in descending order was: root > stem > old leave > mature leave > petiole > bud. There was a significant positive correlation between tenderness of tea leaves and RE2O3 content. It was reported that daily intake of RE2O3 content from diet was 0.133 mg/d, and the intake through tea consumption was estimated to be from 0 mg/d to 0.1129 mg/d, which was far below the acceptable daily intake reported (1.2~57.6 mg/d) and suggested that exposure to level of RE2O3 was quite low. Currently, no standard limit for RE2O3 daily intake has been recommended by government. However, the limit for content of RE2O3 in tea was the same with food crops (2 mg/kg). Tea was different from food crops, so we should take full account of its daily consumption quantity and solubility of RE2O3 for setting the limitation. Consequently, basic researches on RE2O3 in food safety and systemic risks assessment were suggested to strengthen to provide scientific basis for setting safety standards.