【作者】 张强；

【导师】 吴永沛； 黄志勇；

【作者基本信息】 集美大学 ， 食品科学， 2007， 硕士

【摘要】 近年来食品受有毒重金属污染的现象已越来越多地引起人们的重视,但是目前的研究大多侧重于测定食品中重金属的总量,而对其形态的研究相对较少。本论文研究在重金属胁迫下,鱼及蔬菜对重金属吸收和累积的规律,同时采用排阻色谱与电感耦合等离子体质谱联用的方法研究鱼及蔬菜体内重金属的存在形态。研究结果揭示了重金属在鱼及蔬菜体内的吸收、分布和累积特征,以及重金属的主要存在形态,有助于进一步研究鱼及蔬菜在重金属污染环境中的响应机理,以控制食品重金属污染的程度。全文共分为三章:1.重金属污染与食品安全;2.重金属在鱼体内的分布、累积规律及其存在形态的研究;3.芥菜对镉的吸收、累积规律及形态的研究。第一章对食源性动植物受重金属污染的危害和现状进行综述,特别就目前广泛应用于食品中微量重金属检测中的原子光谱分析方法进行了论述。此外,通过对中、外文献的查阅,综述了电感耦合等离子体质谱(ICP-MS)在食品等生物样品中微量元素检测中的应用,以及ICP-MS与高效液相色谱(HPLC)联用技术用于重金属在生物体内结合形态研究的进展。第二章以鲤鱼为实验动物,研究暴露在复合重金属(Hg、Cd、Pb)中的鲤鱼对Hg、Cd和Pb的吸收、积累及多金属结合金属硫蛋白(MTs)的诱导特征。通过比较不同暴露时间条件下重金属在鱼组织中的分布和累积规律,发现吸收重金属在鱼组织中的累积规律为:鳃>肾>肝>肌肉;随着暴露时间的延长,鱼各组织中的多金属结合MTs的诱导量均随之增多。同时,组织中不同重金属诱导生成的MTs量也显著不同,尽管鳃中累积的重金属规律为Hg>Cd>Pb,但Cd-MTs的诱导量远高于Hg-MTs。由于鳃易于累积重金属,并诱导产生大量的MTs。因此,鱼鳃可作为水体微量重金属污染的重要检测器官。第三章以不同形态及不同浓度镉作为胁迫液,研究培养液中的镉在芥菜植株不同组织的分布、累积规律及在其体内的结合形态。结果表明:镉在芥菜植株的累积顺序为根>叶>茎;芥菜对不同镉形态的吸收能力不同,表现为:柠檬酸镉>氯化镉>硝酸镉>EDTA-镉;随着胁迫浓度的增大,芥菜各组织累积的Cd量也显著增大。镉在芥菜组织中的结合形态主要以植物螯合肽(PCs)、类金属硫蛋白(MT-like)及大分子量的蛋白结合形态(HMM),且随着胁迫液镉浓度的增大,HMM含量显著增大。更多还原

【Abstract】 More and more attention has been paid to the heavy metal pollution of food in recent years. However, the researches have been mostly restricted in the determination of the total quantities of heavy metals in food samples. There has been little research about the important chemical species of the heavy metals in food samples. Therefore, in the present study, the absorption and accumulation of heavy metals in fish and vegetables exposed to heavy metals respectively are measured by inductively coupled plasma mass spectrometry (ICP-MS).In addition, the multimetal-binding fractions in the samples are investigated with the hyphenated technique of size-exclusion chromatography (SEC) and ICP-MS. The results may be useful for the further studies about reacting mechanisms of heavy metals of the aquatic products and plants in contaminative environment.The full thesis consists of three chapters: 1. review of heavy metal contamination and food safety; 2. investigation into metal distribution, accumulation and metal-binding metallothioneins in carp exposed in waterborne heavy metals; 3. investigation of cadmium distribution and Cd-binding fractions in mustard cultured in cadmium solution.In the first chapter, the danger and the present situation of heavy metal contamination in foods were reviewed. The discussion mainly focused on the analytical methods of atomic spectrometry generally used in the present for trace heavy metals in foods, and the hyphenated techniques of high performance liquid chromatogram (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS) used for the speciation analysis of heavy metals.In the second chapter, the bioaccumulation of metals and induction of metallothioneins in carp co-exposed to cadmium, mercury and lead were investigated. The results indicated that the accumulation order of three heavy metals was as follows: gills>kidneys> livers>muscle; the amount of MTs induced in fish tissues increased with the longer exposure time. Gill would significantly assimilate heavy metals and the assimilated metals in the gill caused higher MTs concentrations in this organ, therefore, MTs in gill could be used as a marker to reflect the toxic metal pollutionIn the third chapter, the absorption and accumulation of cadmium in mustard stressed with different species and different concentrations of cadmium were investigated. Meanwhile, the cadmium-binding fractions in mustard were analyzed with the hyphenated technique mentioned above. The results indicated that the accumulation order of Cd was ranged as roots>leaves>stems. The main (Cd、Zn)-binding fractions included high molecular mass (HMM), MT-like and phytochelatins (PCs). Comparing with the content of PCs and MT-like, the amount of HMM induced in roots of mustard increased significantly with the higher stressed Cd concentrations.更多还原