Effect of cooking on metal content of freshwater crayfish Procambarus clarkii

Abstract

Zinc, copper, lead, chromium, and cadmium levels were measured using an atomic absorption spectrophotometer in abdominal muscle of freshwater crayfish (Procambarus clarkii). The metal concentrations could be arranged in descending order according to their concentrations in raw muscles: zinc, copper, lead, chromium, and cadmium. After cooking, metals were found in the same order as in raw tissues, except that chromium preceded lead. Zinc concentration was significantly higher than copper, lead, chromium, and cadmium in both raw and cooked muscles. On the other hand, copper concentration was significantly higher than lead, chromium, and cadmium. A significant positive correlation was found between raw and cooked muscle elements. Generally, zinc, chromium concentrations were within the allowable limits in both cooked and raw muscles, but cadmium and lead levels exceeded the maximum permissible limits for human consumption in both cooked and raw muscles. Copper concentrations of cooked muscles exceeded the maximum permissible limits for human.

Keywords:

• Freshwater crayfish
• Procambarus clarkii
• Heavy metals