Study on Extraction and Physiochemicai Properties of Antarctic Krill (Euphausia superba) Astaxanthin
|School||Ocean University of China|
|Keywords||Antarctic krill astaxanthin papain fermentation optimization test|
Antarctic Krill has become one of the marine biological resources that are paidglobal attention in the21st century because of its potential scientiifc value, economicvalue and medicinal value.Among the abundant bioactive substances contained inAntarctic Krill, the astaxanthin caters to the needs of the market at home and abroaddue to its excellent health care function. Antarctic Krill contains a high level ofastaxanthin. Above95%of total carotenoids in its body are astaxanthin. By studyingthe approaches of extracting astaxanthin from Antarctic Krill, the added value of theAntarctic krill product will be highly promoted, which has many economic and socialbenefits.This thesis chooses the Antarctic krill fresh shrimp and shrimp powder as thestudy materials and studies the Antarctic krill astaxanthin extraction technology.Besides，the nature of Antarctic krill astaxanthin has been studied preliminarily.The Single factor experiments and the uniform test are conducted to use theorganic solvents to extract the astaxanthin directly from the fresh shrimp shell ofAntarctic Krill. Among the ifve organic solvents of petroleum ether, dichloromethane,ethyl acetate, ethanol and acetone, acetone is proved to be the best to extract totalcarotenoid (astaxanthin) from Antarctic krill shrimp shell.In the experiments of use papain digestion pretreatment to extract astaxanthinfrom Antarctic krill shrimp shells，the optimal extraction conditions for acetone toextract astaxanthin from Antarctic krill shrimp shell are known as leaching materialliquid ratio1:32(g:mL)，leaching temperature39°C and leaching time of416min.Through the experiments of use papain digestion pretreatment to extract astaxanthinfrom Antarctic krill shrimp shell，the optimum enzymolysis conditions of the enzyme are known as solid-liquid ratio1:113(g:mL)，enzyme-substrate ratio6:100，enzymolysis temperature50。C，enzymolysis time of50min and pH=5. Under theexperimental conditions, each gram fresh dried Antarctic krill shrimp shell that havebeen leaned can produce total carotenoids (astaxanthin) of (350.709±12.060) jig,which is53.214%higher than that directly leaned by acetone of (228.902土6.761)μg/g-In the experiment of extracting astaxanthin from Antarctic krill original shrimppowder by fermentation pretreatment, the yeast has been proved to be the best strainsof fermentation through fermentation strain screening and the optimal fermentationconditions for yeast to ferment antarctic krill shrimp powder have been knew. At last,the fermentation process for yeast to ferment antarctic krill shrimp powder have alsobeen figured out as: inoculate yeast fungus powder into the liquid nutrient mediumaccording to the ratio of1:500(g:ml) and shaking culture them on conditions of300C、130r/min. After48hours, the Antarctic krill original shrimp powder should befermented according to the following conditions: original shrimp powder: yeastfermentation broth1:100(g:mL)，30°C，130r/min and fermentation time12h. Thisexperiment has proved methylene chloride as the optimal extraction reagent throughthe screening test of organic solvents’ extraction ability of Antarctic krill raw shrimppowder astaxanthin. And the optimal extraction conditions for methylene chloride toextract Antarctic krill raw shrimp powder yeast fermentation substrate astaxanthinhave been ifgured out through the single factor and uniform test as: extractionmaterial liquid ratio1:27(g:mL)，extraction temperature19。C，extraction time126min. Under the above conditions, each gram Antarctic krill original shrimp powderactually produces total carotenoids (astaxanthin) of (191±.9114.086) jig, which is24.409%higher than that extracted directly from Antarctic krill original shrimppowder.In the experiment of the inlfuence of Antarctic krill crude oil extraction processand raw materials on the Antarctic krill astaxanthin, the Antarctic krill raw shrimppowder and the supercritical shrimp powder have some influences on the extractionrate of Antarctic krill crude oil and the content of total carotenoids (astaxanthin) from Antarctic krill oil extraction batch. However, the influence of raw shrimp powder issmaller than that of supercritical shrimp powder. The Antarctic krill crude oilextraction rate and the content of total carotenoids (astaxanthin) of supercriticalAntarctic krill shrimp powder are all lower than the Antarctic krill original shrimppowder. The total antioxidant capacity of Antarctic krill original shrimp powder’ sanhydrous ethanol crude oil extraction liquid is191.988Unit/ml, which is21.672times that of supercritical Antarctic krill’shrimp powder s anhydrous ethanol crude oilextraction liquid of8.859Unit/ml.In the experiment of the related factors that influence Antarctic krill ’astaxanthins quality, through analyzing the common factors that influence Antarctic krill’astaxanthin s quality like sunlight, temperature, pH, metal salts and metal ions, thebest storage conditions for Antarctic krill carotenoids (astaxanthin) have been ifguredout as protection from sunlight,4°Cor-20°C，pH=7and protection from contact withthe metal media or metal salts solution.In the experiment of characterization of astaxanthin in the Antarctic krill reifnedoil by liquid chromatography-quadrupole time of ifght mass spectrometry, it’ s apreliminary analysis of the relative molecular mass and molecular composition ofastaxanthin monomer in the Antarctic krill reifned oil through the LC-Q-TOF-MSdetection.