| It is our country’s characteristics that vast waters and rich aquatic resources includinghigh yield of prawn, pacific white shrimp as one of the main prawn species is widely raisedin China. Shrimp meat is the important export commodity, causing lots of processingresidues which were wasted. In order to improve the utilization level of shrimp head waste,to clear the influence of supercritical carbon dioxide extraction’s process parameters on theextraction results and to improve the extraction yield and astaxanthin purity. Thetechnology of supercritical carbon dioxide extraction with no pollution, no solvent residuewas used in this article to extract shrimp oil from the waste of shrimp head, the influencesof extraction parameters on the extraction yield, the composition of fatty acid and theastaxanthin purity were studied, response surface design was applied to optimize theextraction parameters. The saponification process of astaxanthin was optimized and thestability of the pigment was studied based on the extraction of shrimp oil. The resultsshowed that:(1) The effects of extraction pressure, extracton temperature and carbon dioxide flowrate on the shrimp oil yield were not significant, but the addition of ethanol can improvethe extraction yield significantly, the extraction yield can reach up to80.9%with a8%dosage of ethanol.(2) The compositon of fatty acid extracted under different extraction parameters wereanalyed through the technology of gas chromatography-mass spectrometry, there were total23kinds of fatty acids in the shrimp oil, the content of polyunsatured fatty acid was64.69%and the content of DHA and EPA was significantly as high as10.4%(P<0.05) at300bar,45℃.(3) The appropriate levels of saponification time, temperature and the saponifierconcentration were determined through the saponification experiment, the response surfacedesign was appied when the experiment was conducted with the review indicator ofastaxanthin purity. Results showed that the optimal saponification process weresaponification time20.15min, saponification temperature14.94℃, the concentration ofsodium hydroxide-methanol0.05mol/L, astaxanthin purity456.244mg/g. Validationexperiment combined with reality showed that saponification time20min, saponificationtemperature15℃, the concentration of sodium hydroxide-methanol0.05mol/L,astaxanthin purity452.42μg/g. The result of the test gave reference to the separation,purification and quantitative analysis.(4) The influence of supercritical carbon dioxide extraction parameters on theastaxanthin purity was studied through the single factor experiment, the factor level of theresponse surface design were extraction pressure320~480bar, extraction temperature 36~44℃,carbon dioxide flow rate0.7~1.5L/min. The theory optimize result of theextraction parameters were extraction pressure403.95bar, extraction temperature39.93℃,carbon dioxide flow rate1.16L/min, astaxanthin purity796.3μg/g. Combined withapplication, validation result was789.61μg/g at400bar,40℃,1.2L/min. The results canprovide a reference for extraction and purification of astaxanthin.(5) The stability of astaxanthin at different environment including temperature,oxygen and light processing was examined, the results showed that the stability of theastaxanthin was poor and easily influenced by temperature, oxygen and light. The highertemperature, the lower astaxanthin purity, the astaxanthin purity decline faster in contactwith oxygen than airtight processing, the influence degree of the three light processingwere the sun>the natural light>away from light. |
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