Study On Extraction Of Antarctic Krill Oil By Enzymatic Hydrolysis

In this paper,Antarctic krill was used as the main research object.The effects of different protease enzymatic extraction on the lipid yield and quality of Antarctic krill oil were studied,the best suitable protease for extracting krill oil was selected.The two proteases(Alcalase + Compound proteinase)were combined to extract krill oil,and the optimum conditions for extracting Antarctic krill oil by enzymatic hydrolysis were optimized.The best organic solvent for extracting krill oil was selected by comparison and optimizing the extraction process.It is hoped to provide a theoretical reference for the processing and utilization of Antarctic krill,the increase of added value and the industrial production of Antarctic krill oil,and at the same time promoted the resource utilization of Antarctic krill.The effects of Papain,Compound proteinase,Acidic protease,Neutrase,Pancreatin and Alcalase on the lipid yield and quality of krill oil were studied.The contents of vitamins,astaxanthin and phospholipids in shrimp oil extracted by different proteases were analyzed by high-performance liquid chromatography(HPLC).The composition and content of fatty acids were analyzed by gas chromatography(GC).The results showed that the lipid yield,phospholipid content,tocopherol content and vitamin A content of krill oil extracted by Compound proteinase and Alcalase were higher,the content of omega-3 polyunsaturated fatty acids and phospholipids in krill oil extracted by Alcalase was higher.And found by analyzing the data that the content of monounsaturated fatty acids and polyunsaturated fatty acids,vitamin A and tocopherol in krill oil was positively correlated with the yield of krill oil,the effect of different proteases on iodine value was positively correlated with fatty acids.The extraction of krill oil from Antarctic krill by double enzyme combined with organic solvent was studied.The composition and content of fatty acids were analyzed by gas chromatography.First of all,through the comparison experiment,the method of adding Alcalase and then adding Compound proteinase was determined.Secondly,taking extraction rate as index,the effects of the amount of two enzymes and the time of enzymatic hydrolysis on the extraction rate of krill oil were studied.Finally,the effects of enzymatic hydrolysis and organic solvent extraction on fatty acids,acid value,iodine value and peroxide value of Antarctic krill oil were compared.The optimum process conditions determined by single factor experiments and orthogonal experiments are: the ratio of material to liquid is 1:1,firstly,added 0.075% Alcalase to degrades the Antarctic krill at pH 8.00 and 55°C for 2.0 h,then add 0.100% Compound proteinase.enzymatic hydrolysis at pH 7.00,50°C for 3.0 h.Under these conditions,the extraction rate of krill oil is 4.64%,the content of unsaturated fatty acid is 61.47 g/100 g,of which EPA content is 18.73 g/100 g,DHA content is 8.44 g/100 g.Compared with the extraction rate of 2.68%,unsaturated fatty acid content is 56.79 g/100 g by organic solvent extraction method,The extraction rate and unsaturated fatty acid content of crude krill oil obtained by enzymatic hydrolysis are relatively high,and the quality of krill oil is better,which provides a theoretical basis for the process of enzymatic extraction of krill oil.The effects of extraction of six organic solvent such as n-hexane,ethyl acetate,isopropanol,cyclohexane,acetone and petroleum ether on the extraction rate of Antarctic krill oil were studied.The organic solvent with the highest extraction rate was selected,the results showed that the extraction rate of krill oil by cyclohexane was the highest,so cyclohexane was chosen as the extraction solvent.The extraction rate was used as the index to study the effects of the addition ratio of absolute ethanol and cyclohexane,the addition amount of absolute ethanol and the extraction time on the Antarctic krill oil and the optimal extraction conditions were determined.The optimum conditions for the extraction were as follows: Take 50 g of chopped shrimp,added 0.075% Alcalase,enzymatic hydrolysis at pH 8.00 and 55°C for 2.0 h,then add 0.100% Compound proteinase.enzymatic hydrolysis at pH 7.00,50°C for 3.0 h.30 mL absolute ethanol was added and then 60 mL cyclohexane was added after per 30 minutes and repeat the extraction process once.Finally,the applicability of the extraction process to the oil of Antarctic krill,Pacific White Shrimps and Macrobrachium rosenbergii was studied,the extraction rates,fatty acid composition and content,acid value,iodine value and peroxide value of three kinds of oils were compared,the results showed that the optimized extraction technology could also be used to extract other oil and the quality of shrimp oil is better than that of organic solvent extraction.It provides theoretical support for the utilization of Antarctic krill and other shrimp and their wastes.