Effect Of Dry Process On Lipid Quality Of Antarctic Krill Oil By Antarctic Krill Powder And Enzymatic Solvent Method

Antarctic krill(Euphausia superba)is an important marine economic animal.Since 2009,the Antarctic krill has been explored and the development of Antarctic krill resources has risen to a national strategy.Antarctic krill is rich in protein,astaxanthin and polyunsaturated fatty acids,but its stability is poor,and it is highly prone to oxidation and reduce biological activity during processing and storage.The traditional Antarctic krill powder processing technology is divided into cooking,dehydration,hot air drying,pulverization and the like,but the nutrients in the Antarctic krill are susceptible to thermal decomposition,which deteriorates the quality of the shrimp powder.This study compared the basic nutrient composition of Antarctic krill powder with different drying methods,and investigated the effect of drying process on key nutrients in Antarctic krill powder.Antarctic krill powder is usually used as a raw material for extracting Antarctic krill oil.The traditional solvent extraction method has low extraction efficiency.The enzymatic assisted solvent method can improve the extraction efficiency of oil and fat,and has the advantages of mild conditions and simple operation,but different proteases.The effect on the quality of the extracted oil in the enzymatic assisted solvent method has not been reported.This study will examine the key indicators of Antarctic krill oil prepared by different protease assisted solvent methods,and reveal the effect of enzymatic hydrolysis on the quality of oil.The four kinds of Antarctic krill powders were directly prepared by direct air drying and direct drying,direct lyophilization,enzyme lyophilization and enzyme heat drying.The differences in basic nutrient composition and key lipid indexes were compared to reveal different drying methods.The effect of the quality of shrimp powder.The results showed that the boiled and purified shrimp powder had lower oil,astaxanthin,phosphatidylcholine(PC),phosphatidylethanolamine(PE),eicosapentaenoic acid(EPA).The content of docosahexaenoic acid(DHA)indicates that boiled enzymes accelerate the hydrolysis of lipids in shrimp powder;while hot air drying is more likely to cause oily astaxanthin,PC,PE in shrimp powder than freeze-drying.The decrease in the content of nutrients such as EPA and DHA and the increase in thiobarbituric acid value(TBARS)and acid value(AV)indicate that heat-drying accelerates the oxidation and hydrolysis of lipids.In summary,hot air drying will accelerate the oxidation and hydrolysis of lipids,leading to the loss of nutrients in Antarctic krill powder.Although the hydroponic enzymes cause the hydrolysis and oxidation of lipids to some extent,in the actual production,the enzymes are eliminated.The processing and storage can slow down the loss of nutrients,so the Antarctic krill powder prepared by the enzyme and lyophilization method has better quality.The antarctic krill oil was extracted by adding neutral protease and alkaline protease,and compared with the control group,the neutral protease group,the alkaline protease group,the inactivated enzyme control group,the inactivated neutral protease group,and the inactivated alkaline protease group.The oil extraction rate of the sample and the content of key nutrient components in the oil showed the effect of enzymatic assisted solvent extraction technology on the quality of Antarctic krill oil.The results showed that the oil extraction rate of shrimp powder increased significantly after enzymatic hydrolysis(P<0.05),while the oil extraction rate of alkaline protease group was higher than that of neutral protease group,indicating that the hydrolysis efficiency of alkaline protease was higher than that of neutral protease.The addition of protease caused the increase of astaxanthin,PC,PE,polyunsaturated fatty acid(PUFA)content and AV and TBARS,indicating that the enzymatic hydrolysis of protein promoted the release of lipid and accelerated the oxidation and hydrolysis of lipid.However,the rate of increase of astaxanthin,PC,PE and PUFA in the alkaline protease group was lower than that of neutral protease,probably due to the spontaneous degradation of lipid under alkaline conditions.Enzymatic processing of Antarctic krill before enzymatic hydrolysis can significantly increase the content of astaxanthin,PC,PE and PUFA in the extracted oil,and reduce AV and TBARS,indicating that the enzyme can effectively inhibit the endogenous enzyme in the hydrolysis process.Oxidation and hydrolysis of lipids.