Forms And Toxicity Of Fluoride From Antarctic Krill

Antarctic krill has comprehensive nutrients,balanced and reasonable distribution ratio,and huge resource reserves,which is considered to be an important reserve protein library for humans with broad application prospects.However,the large-scale commercial use of Antarctic krill is restricted by its high fluoride content.Fluoride is one of the essential trace elements of the human body,and it is also a type of double-threshold element.Excessive intake of which will cause a series of damage to biological bodies.Related research on fluoride in Antarctic krill is one of the hotspots that have received attention,but until now,there has been no breakthrough progress in the study of the forms of fluoride in Antarctic krill.In this paper,three aspects of research were carried out.Firstly,the forms of part of fluordie from Antarctic krill are analyzed and confirmed by ¹⁹F Nuclear Magnetic Resonance(¹⁹F NMR),Fourier Transform-Infrared Spectroscopy（FT-IR）and Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy（SEM-EDX）;Next,the Bioaccessibilty of total fluoride and different forms of fluoride are analyzed;finally,the oral acute toxicity and chronic toxicity of fluoride from Antarctic krill are analyzed.The conclusions of whom are shown as following:1. The forms of part of water-soluble and residual fluoride in Antarctic krill have been initially clarified:It’s confirmed by liquid ¹⁹F NMR that part of water-soluble fluoride exists in the ion form of F^-,HF₂^-,and Al F₆^-,and there is also part of water-soluble fluoride exist in the form of HF and Mg-F bonds;meanwhile,FT-IR and SEM-EDX prove that part of residual fluoride from Antarctic krill shell exists in the form of fluorapatite.2. The bioaccessiblity of total fluoride and different forms of fluoride from Antarctic krill are proved as follows:From the perspective of total fluoride,Whole forzen Antarctic krill and Antarctic krill meat have a low fluoride background content,and the amount of fluoride dissolved in the digestion process is small,but the bioavailability is relatively higher;Antarctic krill shells and Antarctic krill powder have a high fluoride background content,and more fluoride is dissolved during the digestion process,but the bioavailability is relatively low;The dissolution of fluoride in whole Antarctic krill and Antarctic krill meat mainly occurs in gastric juice（78.18%and 69.45%）rather than intestinal juice（7.47%and 9.34%）;Antarctic krill shell and Antarctic krill meat in gastric juice（32.53%,12.09%）and intestinal juice（16.13%,16.21%）have certain dissolution.From the perspective of different forms of fluoride,For Antarctic krill powder,organically bound fluoride and residual fluoride have higher bioavailability than water-soluble fluoride,exchangeable,and oxidized fluoride during the entire digestion stage;and organically bound fluoride and residual fluoride Fluoride will be transformed into three other forms during digestion;On the other hand,whole shrimp and shrimp meat show the opposite trend to shrimp powder,that is,the bioavailability of water-soluble fluoride and exchangeable fluoride is higher.From the perspective of the kinetic process of the digestion reactions,In the digestive phase of gastric juice,the amount of fluoride dissolved in krill powder showed a rapid increase-decrease-slow increase trend,but in the digestive phase of intestinal juice,it showed a steady increase trend.This phenomenon is caused by the transformation of different forms of fluorine in Antarctic krill.3. The oral acute toxicity and chronic toxicity of fluoride from Antarctic krill are proved as follows:The oral lethal dose(LD₅₀)of Antarctic krill powder is greater than 20 g/Kg Bw.According to the national standard,the acute toxicity level is"actually non-toxic".However,the determination index of toxity and food safty of Antarctic krill still needs to be further improved by relevant research and data.Fluoride in Antarctic krill powder has no significant effect on the lipid metabolism-related indicators of the tested animals,but will cause oxidative stress in the tested animals and reduce the body’s antioxidant capacity;while the fluordie cause potential kidney damage and liver damage through oxidative stress.But these damages and negative effects are weaker than sodium fluoride.Fluorine in Antarctic krill powder is significantly accumulated in bones and teeth,but the accumulation degree is significantly weaker than sodium fluoride;Among organs susceptible to oxidative stress damage,Antarctic krill fluoride shows only a slight accumulation in the lungs that is comparable to sodium fluoride levels and is not significant;Both Antarctic krill fluoride and sodium fluoride showed no accumulation in other soft tissues.testes and ovaries of the brain,spleen,heart and reproductive organs.