Research On Preparation Of Defluorination Polypeptide From Euphausia Superba And Study Of Polypeptide’s Activity In Vitro

Euphausia superba contains abundant protein, it has very high nutritional value,including the8essential amino acids which all the human body needs.Besides, theproportion between essential amino acids and non-essential amino acids is suitable. Itcan contribute to the body to absorb and utilize nutrients.This research preparespolypeptide extract from Euphausia superba by adopting enzymatic hydrolysismethod, which can beneficial to the resources utilization of Euphausia superba, andcan provide high quality as well.Since it has broad development and applicationprospect, using the enzymatic hydrolysis method to extract marine organism’spolypeptide can often be reported. However, the research on preparation ofpolypeptide from Euphausia superba and its activity research report has not beenseen.This study optimize the preparation polypeptide from Euphausia superba to getthe the optimal technical condition. This study provides the theoretical foundation toexplore the development and utilization of the Euphausia superba peptide, which hassignificant economic and social value.This research prepares polypeptide extract from Euphausia superba by adoptingenzymatic （papain） hydrolysis method. We use the “orthogonal analysis” software tofix on the optimal hydrolysis conditions. On which basis, the polypeptide is handlingby the defluorination procedure. Meanwhile, the studies of in-vitro anti-oxidative andreducing blood pressure active of the poltpeptide are also conducted. This researchcan be divided into three parts.PartⅠ：Preparation and component analysis of polypeptide from Euphausia superbaBy adopting enzymatic （papain） hydrolysis method, polypeptide from Euphausiasuperba is preparated. The effect factors, including material/liquid ratio, enzymedosage, temperature, pH and hydrolysis time, were investigated through orthogonal tests L9（34）on the basis of single factor experiments.Analyzing data to determine thebest preparation conditions and determinating the main component of the peptideliquid under this condition.Part Ⅱ：Defluorination procedure of the polypeptide from Euphausia superbaAfter handled by hydroxyl phosphorylation procedure, the raw material （oyster s-hell powder） become a kind of novel defluorination material.The best preparation conditions is obtained by single factor experiment, under which the defluorinated effici-ency can be highest.The adsorption performance of the defluorination materialis determined at the same time. At last, using the peptide liquid as the original liquid, material’s defluorinated efficiency is determined through static adsorption experiments and dynamic adsorption experiment respectively.Part Ⅲ：Study of polypeptide’s antioxidant and reducing blood pressure activityin vitroThe activity study in vitro is conducted after optimization and defluorinationpoprocedure with polypeptide liquid. The DPPH method and the pyrogallolautoxidation method can be used to investigate the polypeptide’s scavenging hydroxyland superoxide anion free radical ability respectively. Besides, the polypeptideliquid’s reducing blood pressure activity in vitro is investigated with the method ofdetermine inhibition ratio on angiotensin converting enzyme （ACE）.Conclusions: By using “orthogonal analysis” software, the optimal hydrolysisconditions utilizing papain were as follows: protease addition3000U/g, temperature55℃，ratio of material with liquid1:2, pH7.0and hydrolysis time3h. Theexperimental result shows that under the optimal conditions, the hydrolysis degree canreach up to24.73%. The main components are as follows: the polypeptide content andthe amino nitrogen content are87.32%and2.87%respectively. Polysaccharideaccounted for4.7%, fat accounted for0.83%and ash accounted for23.19%. Throughthe single factor experiment，the preparation conditions of maximum rate ofdefluorination can be found as follows: ratio of material with solid1:50, immerse time6h, aging pH10.0. It has high efficiency in the range of pH4～10. The influence ofco-existing Cl^-or SO₄^2- is low, which show that the material has high ablity of anti-interference.In theory,the absorbing capacity of saturating is8.13mg·g^-1.Usingthe new-type material,the defluorination adsorption experiments is carried out. Theresults show that, the removal percentage of fluoride is95.64%under the staticadsorption condition.While the removal percentage of fluoride can reach up to98.71%through dynamic batch experiments, and the maximum adsorption capacity isbeyond4.67mg/g.The polypeptide from Euphausia superba with defluorinationprocedure is very effective in antioxidantion as well as reducing blood pressure. IC₅₀are3.63mg/mL and11.72mg/mL respectively. Comparing with Vitamin E，thepolypeptide has excellent antioxidation ability to eliminate radicals. Besides, thepolypeptide liquid’s has high inhibition ratio on angiotensin converting enzyme（ACE）, its IC₅₀is10.87mg/mL.