Study On The Compound Preservative Technology Of Ready-to-eat Flavored Crayfish

Crayfish(Procambarus clarkii)are delicious and nutritious.It is one of the best-selling freshwater shrimp in the aquatic market.Due to geographical and seasonal influences,most of them can only be sold in a fresh way,which limits the development of the crayfish industry.Moreover,crayfish food are high in protein and water,thus it is extremely susceptible to microbial contamination and spoilage,making it difficult to store.To solve the urgent problems of spoilage and short shelf life,using fresh crayfish as raw materials in this dissertation,a ready-to-eat crayfish product was prepared through a certain processing technology,and then stored at37 ? for further research.Combined with sterilization temperature,vacuum packaging materials and composite preservatives,antibacterial and freshness experiments of ready-to-eat crayfish were carried out,which has important practical significance for the industrial production of ready-to-eat crayfish.The main research contents include the following aspects:(1)Using sensory characteristics,physical and chemical characteristics,and the total number of colonies as indicators,the effects of different back-pressure sterilization temperatures on the quality of ready-to-eat crayfish were compared and the appropriate back-pressure sterilization temperature was determined.It was indicated that the quality of ready-to-eat crayfish sterilized at 110? for 20 min was superior,and the microbial survival rate was low.(2)On the basis of the above result,the effects of different vacuum packaging materials(I: PA/CPP;II: PA/PE/RCP;III: PET/AL/NY/CPP;IV: PET/AL/PA/CPP)on the quality of ready-to-eat crayfish were compared.It was showed that the oxidation rate of ready-to-eat crayfish in the No.? packaging bag was the slowest and the sensory evaluation was the highest.(3)Based on the single factor experiment,through the orthogonal experiment design,the total number of colonies and TVB-N values are used as the evaluation indicators to obtain the optimal preservative ratio.When ?-polylysine is 0.22 g/L,sorbus potassium acid is 0.90 g/L,sodium dehydroacetate is 0.45 g/L,and Nisin is0.45 g/L,the preservation effect is the best.Crayfish were treated with the optimal composite preservative,packed in a No.IV packaging bag,sterilized at 110? for 20 minutes,and stored at 37? to study the shelf life of ready-to-eat crayfish.The resultsrevealed that crayfish treated with the optimal composite preservative had a longer shelf life,and no Escherichia coli and pathogenic bacteria were detected at the end of the shelf life.