加工精度对大米重金属的影响规律及品种差异

Research of the Change Rlue of Heavy Metal Content and its Difference in Varieties During Rice Processing

在湖南省选择5种不同品种的稻谷样品,经过砻谷和碾白,将稻谷加工成不同加工精度的大米,分别测定其总砷、汞、铅、镉的含量,旨在探讨加工精度与重金属含量的变化规律及品种间的差异性。结果表明,四种重金属在稻谷中分布极不均匀,除稻壳外,重金属含量由外到内逐渐降低;随着加工精度的提高,总砷、汞、铅、镉含量均呈下降趋势。因此,通过加工精度的提高,可在一定程度上降低加工产品中总砷、汞、铅、镉的含量,当稻谷的碾减率达到20%时,其总砷、汞、铅、镉含量的下降率可达53.7%、29.2%、57.5%和33.3%。此外,四种重金属在稻谷中的分布呈现一定的品种差异。

Rice sample with five different varieties was chosen for the determination of the content of total As,Hg,Pb,Cd in rice with different milling degree after husking and milling process.The change rule of these heavy metal contents and its difference in varieties during the rice processing were discussed.The results indicated that the distribution of these heavy metals in rice was exactly non-uniform.Besides the rice husk,the content of these heavy metals reduces gradually from outside to in.Meanwhile,all the contents of the four kinds of heavy metals were reduced with the improvement of milling degree.As a result,the content of the total As,Hg,Pb,Cd in rice could be reduced by increasing the milling degree of rice.When the milling degree of rice reached to 20%,the reduction ratio of total As,Hg,Pb,Cd would be 53.7%,29.2%,57.5 and 33.3%,respectively.Besides,the change rule of these heavy metal contents rice was different with its varieties.