Optimization Of Enzymatic Hydrolysis Of Antarctic Krill And The Analysis Of Flavor Components

Antarctic krill(Euphausia superba)is rich in nutrients,rich in protein,fatty acids,amino acids,astaxanthin and other nutrients,and it has become a hot spot in the world.The study found that after the enzymatic hydrolysis of Antarctic krill,macromolecular proteins and fats can be broken down into small-molecule amino acids and fatty acids,and the resulting product is more conducive to human body absorption and utilization.However,there are no detailed studies on the enzymolysis technology of Antarctic krill and the analysis of nutrient components of the hydrolysate.In this paper,the experimental design of the current problem of Antarctic krill was carried out.Firstly,the process of enzymatic hydrolysis of Antarctic krill was optimized.Secondly,the nutrient contents of Antarctic krill after enzymolysis were analyzed.On this basis,the flavor components of the Antarctic krill in different processing methods were analyzed and researched,aiming to provide theoretical support for the development and utilization of Antarctic krill,a huge protein resource.The main research contents and conclusions are as follows:Optimization of Enzymolysis Process of Antarctic Krill.The main processes include: A ntarctic krill cleaning and pretreatment ? Pulverization ? Enzymatic digestion ? Inactivati on ? Centrifugation ? Supernatant ? Detection and analysis ? Process optimization.The optimization of the process is mainly a response surface optimization method.Firstly,after th e enzymatic treatment of Antarctic krill by different enzymes,the protease was screened by th e degree of hydrolysis and the content of peptides as indicators,and finally the selected papai n was considered as the Antarctic krill enzyme.Next,a single factor experiment was conducte d to optimize the enzymatic hydrolysis conditions of papain with the degree of hydrolysis as a n indicator.The single factor screening was performed using the four factors of enzyme additi on amount,pH,enzymolysis time and enzymatic hydrolysis temperature,and 3% was selected by experimentation.,4%,5% as the level of response surface of the enzyme addition amoun t,select 6,7 and 8 as the response surface level of p H,select 2h,3h,4h as the response surfac e level of enzymatic hydrolysis time,select 50°C,55°C,60 °C as the response surface level of Antarctic krill enzyme digestion temperature.Finally,the four-factor and three-level experim ent of the response surface were determined.Through the optimization of response surface ex periment,the optimum parameters for the enzymolysis of Antarctic krill were obtained as foll ows: the enzyme dosage was 4.73%,the pH was 7.00,the enzymolysis time was200 mins,and the enzymolysis temperature was 54°C.Under this condition,the theoretical degree of hydr olysis of Antarctic krill is 41.2%,which is significantly higher than the degree of hydrolysis o f the Antarctic krill hydrolysate before process optimization.Antarctic krill hydrolysate product nutritional determination.Firstly,the Antarctic krill w as digested with an enzyme addition amount of 4.73%,a pH of 7.00,an enzymolysis time of 200 mins,and an enzymolysis temperature of 54°C.to obtain an Antarctic krill hydrolysate.Th e final analysis of the test results showed that the crude protein content of Antarctic krill befor e enzymatic hydrolysis reached 68.95% and the crude fat content was 13.23%.The detected A ntarctic krill contained 18 kinds of amino acids,including 8 kinds of essential amino acids an d 10 kinds of non-essential amino acids,and 6 kinds of taste-producing amino acids.The esse ntial amino acid index(EAAI)of the Antarctic krill was 52.72,and the essential amino acid in dex(EAAI)of the lyophilized supernatant of the Antarctic krill after the digestion was 56.31.Antarctic krill found in the original shrimp contains 20 kinds of fatty acids,unsaturated fatty a cid content reached 56.95%,including monounsaturated fatty acids 27.56%,polyunsaturated f atty acids 29.39%.There are 8 kinds of saturated fatty acids,accounting for 43.05% of the tot al fatty acid content;EPA content is 13.92%,DHA content is 10.24%.It can be seen that Ant arctic krill is indeed a very precious resource for our humanity.Enzymolysis liquid flavor composition analysis.The sensory evaluation method and elec tronic nose method were combined to detect the differences in the flavor components of the A ntarctic krill with different thawing methods and different enzymatic methods.Natural thawin g is obviously the most undesirable one among different thawing treatments.After a long-ter m thawing in the natural state,the surface of the whole piece of Antarctic krill directly expose d to the air became black and deteriorated.After the detection of the flavor,the proportions of odor,ammonia and bitterness components were significantly increased..The results of the A ntarctic krill after hydrolytic or cryogenic thawing are much better,mainly due to the large pr oportion of umami and fishy odor;and the color of the shrimp is also bright.In the process of enzymolysis of four different enzymes,the treatment of papain is the best one based on sensor y evaluation.Both umami and meat flavor are relatively full,and the clarity of the enzymatic hydrolysate obtained is also better.High;Neutral protease,alkaline protease followed;Acidic protease is the worst kind of effect,mainly umami and enzymolysis solution are clear.