The Research On The Quality And Dynamics Of Antarctic Krill During Frozen Storage

This topic investigated physical and chemical indicators and structure change ofthe Antarctic krill frozen at different temperatures, and then according to the Arrheniusequation, the dynamic analysis for chemical quality was studied. Based on researchresults, the Antarctic krill shelf life prediction and freezing storage work was guided toperform under different frozen storage temperatures.For the Antarctic krill meats frozen in-18,-25,-30and-50℃respectively,physical and chemical analysis and Texture Profile Analysis (TPA) methods were usedto analysis10indexes including TVBN, dressing percentage, pH, moisture content,soluble protein, elastic, restorative, glue viscosity, hardness and chewiness. As theextension of storage time of Antarctic krill meat, TVBN value grew obviously, and themaximum rising rate reached0.0541. After50days, the growth of the meat TVBNvalue was becoming slower, which average increase rate is0.0191. After180days,dressing percentage of the meat frozen in-18℃dropped39%, and the soluble proteincontent was0; meat frozen in-50℃dropped18%, and the soluble protein contentdropped to79mg/100g. Moreover, TPA indexes of the Antarctic krill meat frozen in-18℃were all lower than those of other three temperatures. Physical and chemicalindicators and TPA of krill meats frozen in-25and-30℃were between those of-18and-50℃. Influence of freezing storage temperature on the Antarctic krill oil extraction was researched in this study. Response surface method was used toeffectively optimize the extraction condition of the Antarctic krill oil. Antarctic krill rawshrimp oil yield is highest when the conditions of freezing storage temperature was38.5℃, solid-liquid ratio was1:6.7, and the drying temperature was66.8℃, andunder these conditions, the Antarctic krill raw shrimp oil yield was13.71%.The Antarctic krill refrigerated for200days in255K (-18℃),248K (-25℃),243K (-30℃) and223K (-50℃) were used as samples. In order to seek the influenceof temperature and time to the Antarctic krill quality, the pH, the content of moisture,dressing percentage, the water holdup, TVBN and soluble protein content were used tobe physical and chemical specifications. It was concluded according to physical andchemical analysis and sensory evaluation that, in the same storage time, the lower thetemperature could reduce, the better the quality of the Antarctic krill could get. Thededuction as follows could be obtained from the analysis of the experiment data by thechemical kinetics of quality: the chemical kinetics of quality with time fit the first orderkinetics, expressed by ln([A]/[A0]) k1.texcept the pH whose kinetics with time fitthe second order kinetics, expressed byY Constant k t kt212. Factor analysis isused in data reduction to identify a small number of factors that explain the most of thevariance observed in a much larger number of manifest variables, so it is used to reducethe data of analysis of physical and chemical. Through the factor analysis, the allcriterions of the Antarctic krill refrigerated in255K,248K and223K can be replacedby two factors, which reflect the85%information upwards of all. And the87.597%information of all criterions of Antarctic krill refrigerated in243K can be replaced byone factor. All information rate of sensory indexes of the Antarctic krill in allexperimental temperature were reflected by a principal component, its value is higherthan90%. In subsequent distance correlation analysis, the physical and chemicalsynthesis factor F1and sensory factor can show good correlation under all thetemperature conditions. Therefore the designed sensory index can reflect the change ofphysical and chemical indicators, and can well meet the quality change trend.