بررسي مقدار فلزات سمي كادميوم ، كرم ، سرب و جيوه در رب گوجه فرنگي در شهر اصفهان

Study of the Toxic Trace Elements Cadmium , Chromium , Lead and Mercury in Tomato Paste in Isfahan City

Toxic metals such as Cd, Cr, Pb and hg, in trace amounts, enter the human body through food products. One of the main sources is the corrosion of the metal made apparatus, which are used in the process of food production. Tomato paste with an average ph value of 4.6 capable of containing such elements. The effect of metallic apparatus on the concentration of toxic metals in tomato paste was evaluated. For this purpose 50 samples of tomato, 25 samples of tomato juices and 61 samples of tomato pastes were collected , and digested with nitric acid. Cadmium and chromium were determined, using atomic absorbtion (AA), lead (Pb) were determined using diphenylcarbazid and spectrophotometer. Mercury (hg) was determined using cold vapor AA. Statistical method , ANOVA and Dunken tests were used for data analysis. The percent of recovery of the methods were also determined. The results of the study indicated that the recovery of the methods were over than 93 percent, using the spiked samples of I and 5 PPM of the metals. The results of the study also showed that the concentration of the Cd, Cr, and Pb were below the standard level in home made tomato paste samples. The concentration of hg in all samples were below the standard level and the detection limit of the instrument used. The study also revealed that absence of Hg in all samples could be because of the lack of this element in the percent impurity of the apparatus used . Statistical analysis showed the significant differences between the methods of preparation of tomato paste which confirm the role of non-standard apparatus in increasing the concentration of toxic elements in tomato paste.