Experimental Study On The Shelf Life Of Sea Food Using Ultral-High Pressure Technology

The ultral-high pressure technology for food processing has attracted wide attention in both academia and industry for its advantages,such as sterilization,fresh-keeping, energy-saving,environment-protecting,and so on.The ultral-high pressure treatment can effectively keep the original flavor,color and quality of food,and decrease actibity of microorganisms and enzymes,meanwhile improving the shelf life.The ultral-high pressure technology for food processing overcomes the defect of the traditional keeping-fresh process effectively,and injects the new activation into the food processing industry.Post-harvest seafood spoilage easily,due to the effects of microorganisms and enzymes.The use of high pressure treatment can effectively decrease activity of microorganisms and enzyme,extend the shelf life of seafood.However,the mechanism of ultral-high pressure process is not clear now.To enlarge industrialization of the high-pressure preservation,a large amount of fundamental research has to be carried out.In this paper,ultral-high pressure technology has been carried out,choicing high value-added seafood(oysters,sea cucumber) for preservation of high pressure experiments.In accordance with sterilization—blunting enzyme—keeping-fresh—quality attributes,the effect of high pressure processing on shelf life is carried out.The work and results is as follow:(1) With reference to food hygiene standards,oysters and sea cucumber were investigated to study the impact of ultra-high pressure on the changes of index of microorganisms.The results showed that the total number of colony increased with the increase of pressure,sterilization rate could be improved by extending the pressurization time and increasing the temperature,but the way of pressurization had little effect on sterilization rate.The re-growth of the remaining bacteria dealt with ultra-high pressure was also studied.The results indicated that ultra-high pressure could restrain the re-growth of the remaining bacteria,the higher the pressure was,the more notable the effects of restraining was;(2) Sea cucumber was treated with ultra-high pressure technology to assesse the effects of processing pressure,pressurization time,temperature and the way of pressurization on the activity of the autoenzyme of sea cucumber.The best processing condition was educed and the conception of critical processing pressure,critical pressurization time and critical medium temperature was put forward.The changes of autoenzyme were investigated.The results indicated that the activity of sea cucumber's autoenzyme showed a decreasing trend and the activity of autoenzyme had little relationship with high processing pressure;(3) Oysters and sea cucumber was treated with ultra-high pressure technology.Then the impacts of ultra-high pressure on keeping flesh of seafood were studied by testing the appearance,pH value and TVB-N after processing.The results showed that ultra-high pressure technology could extend the time of fresh-keeping;(4) Oysters and sea cucumber was treated with ultra-high pressure technology.The effects of ultra-high pressure on moisture,ashes,protein and polysaccharide were studied; Increased in the moisture content,relative to untreated samples,ash contents were reduced with increasing treatment pressure.Ultra-high pressure can induce protein denaturation and not significantly affect polysaccharide;Through experimental study,the high pressure technology for food processing is understood more deeply.So does the effects of every operation parameter on sterilization rate, activity of the autoenzyme,fresh-keeping and quality,which offered an essential basis for the theoretical research of this process.