A new multistage counter current extraction method of removing fluoride from defatted Antarctic krill powder

This study aims to find an efficient acid extraction method to remove fluoride from defatted krill powder. Considering the effects of acid species, concentration, temperature, extraction time, solvent volume on the defluoridation efficiency, and final product yield, a new multistage counter current extraction method was developed. The optimum reaction condition was obtained by adding 10 ml of 0.3 M HCl to 1 g defatted krill powder and extracting for four stages, each stage was lasting for 60 min. After this process, fluoride content per dry weight of the final product was remarkably reduced to <5 mg/kg, defluoridation efficiency was 99.70%, and water consumption was minimized. Fourier transform infrared spectroscopy also indicated a decrease in the amount of fluorine, and basic chemical composition measurement indicated krill protein was not damaged during this process. Therefore, these results could be used as theoretical guidance for removing fluoride in practical application. Practical applications Defatted Antarctic krill powder is a cheap by-product after krill oil extraction, but it contains both high-quality protein and high concentration of fluoride. The toxicity of fluoride in krill powder makes it not be allowed as food resource. So, a new counter current extraction method was developed to defluorinate from defatted krill powder, which was an easy and cheap process, but high defluoridation efficiency with low water consumption. It has been successfully applied to the food pilot base, and it would help to obtain the safe defatted Antarctic krill powder in krill industry.