Study On Defluorination Methods Of Antarctic Krill

Antarctic krill(Euphausia superba), located in the Antarctic waters of the Southern Ocean south of the Antarctic convergence zone, is coldwater shrimp living under conditions of low latitudes. Antarctic krill huge potential resource, estimated at(6.5 ~ 10) × 10 t, is one of the most abundant reserves of an alternative usable of marine animal resources. Antarctic krill is nutritious and rich in protein.In addition to protein, it contains all the essential amino acids, the content of which is rich and proportion of which in18 amino acids is better than other shrimps. The composition and ratio of amino acids is more reasonable. It is rich in linoleic acid, linolenic acid and other unsaturated fatty acids, also contains high antioxidant activity astaxanthin; also contains a variety of mineral elements such as calcium, potassium, magnesium, strontium and high activity endogenous enzymes.Antarctic krill received more attention from the world because of its huge biomass and potential value of fisheries resources. Antarctic krill,which is rich in protein and other nutrients, is important quality biological protein library of human, but high fluoride content is bottleneck that has been restricting its processing and safe use. In order to increase the added value of Antarctic krill and develop more deep-processed products, this paper study defluorination method of Antarctic krill, which contains chemical, physico-chemical and biological methods to defluorinating.Antarctic krill contains a large amount of fluorine, most of which present in the way of bound state in the shrimp shells.Shrimp meat(accounting for 43.03% of dry weight) also contains 333 ± 2mg / kg of fluorine, which do not meet FDA standards(100mg / kg). High content of fluorine is the bottleneck of affecting the development and utilization of Antarctic krill, so chemical treatments with heating and unheating are used to defluorination of Antarctic krill and content of hydrolysis amino acids and crude protein after chemical treatment were measured. The used chemical agents are hydrochloric acid, sodium sulfite, sodium chloride, citric acid, acetic acid, and hydrochloric acid betaine. Fluoride contents per dry weight were 1138±1 mg/kg in the whole body of krill(WBK)and 333±2 mg/kg in the peeled krill meat(PKM) respectively. When WBK was treated with chemicals with and without heating, Decreasing effects of fluoride contents is not significant. The effect of defluorination by chemical treatments with heating is more significant than without heating. Particularly, the treatment of betaine without heating showed the best reduction effect of 48±9mg/kg and the highest defluorination efficiency of 85.59%, followed by citric acid(52±11mg/kg,84.38%), acetic acid(55±6mg/kg,83.48%)and hydrochloric acid(62±5mg/kg,81.38%). However, chemical Defluorination had damaging effects on the hydrolysis amino acids and crude protein, loss of hydrolysis amino acid, flavor amino acid and crude protein after betaine is least. Hydrochloric acid caused the most damage for the shrimp, but changes in the functional properties of the protein caused by chemical treatment need for further research and find effective control methods.As our country’s economic growth, demand for fruits is also growing.But the consequent peel has not been effectively developed and utilized for long time. In peels, there are cellulose, hemicellulose, lignin and pectin, and these molecules surface contain a large number of reactive functional groups, such as carboxyl, hydroxyl, etc. These reactive functional groups may exchange ion, thereby performing ion adsorption, have a good adsorption capacity. If using peel adsorbing directly, adsorption capacity is small, and the performance is unstable, therefore, in this article peel would be modified to adsorb Antarctic krill fluorine experiments, the effect of factors defluorination were studied and optimized, thereby in order to continue the removal of fluoride Antarctic krill provide a scientific basis. Fluorinated using modified peel on Antarctic krill paste, the effect was significantly higher than the unmodified peel. Defluorination effect of modified orange peel was best, and modified grapefruit peel can also reach 63%. In condition of the adsorption time 120 min, the acidic p H, amount of 1g modified peel adsorption effect was best, but the best defluorinated rate only reached about 66%. Modified peel adsorption process follows second order reaction mechanism can be used to associate the secondary adsorption kinetic equation which could be described well, the adsorption rate controlled by chemical adsorption. Modified peel raw could be got extensively, cost lowly, and its manufacturing process was simple, it could do some reference to defluorinated Antarctic krill.In order to achieve safety for consumption requirements, it needs to removal fluorine in krill. Calcium precipitation method is the conventional treatment methods for chemical sedimentation defluorination, the principle is Ca2 ++ 2F- = Ca F2. The method is simple, easy to handle, cost lowly, widely used in treatment about industrial wastewater containing flours. In this study, calcium salt(chitosan, calcium oxide, calcium chloride, calcium carbonate, calcium Portugal Sugar Sugar) method of defluorination on Antarctic krill was used, and the effect of defluorination factors(p H, reaction time, etc.) were researched, in order to further explore the krill and shrimp paste shrimp processing and utilization, to prepare for the requirements of safe to eat. we would solve the difficulties in the future about the remnants of calcium ions in the solution which have bitter taste, this needs to join the masking material or flavorings, the state of fluorine in the Antarctic krill needs to be further researched which has great significance on defluorination.