Effects of Cooking Methods on Heavy Metal Levels in Crayfish Tail and Cooking Juice

Abstract

In order to explore the accumulation of heavy metals in crayfish cooking juice and its effect on the level of heavy metals in edible parts (crayfish tail) under different cooking methods. The levels of nine heavy metals As, Ba, Cd, Cr, Cu, Hg, Mn, Ni, and Pb in crayfish tails and cooking juice at different stages were detected by inductively coupled plasma spectrometer (ICP-OES) under three different cooking methods: Boiling, frying and seasoning. The single factor pollution index was used to judge the heavy metal pollution degree of crayfish tails, and the influence of heavy metal accumulation in cooking juice on crayfish tails was explored by correlation analysis. The results showed that high concentrations of Mn and Cu were observed in the crayfish boiling juice, the concentrations of toxic elements As and Cr increased by 88.8% and 80.7% in the crayfish frying oil, respectively. Furthermore, the concentration of Mn in the crayfish seasoning sauce increased by about 5.4 times compared with the control. With the increase of complexity of cooking method, the level of most heavy metals in the cooking juice would accumulate gradually with the processing process. The correlation analysis revealed that there was a significant positive correlation between heavy metals in the cooking juice and certain metals in crayfish tails (P<0.05), and crayfish tails were susceptible to Mn contamination during the boiling and seasoning cooking process.

Keywords

• crayfish
• cooking methods
• heavy metals contamination
• cooking juice
• icp-oes