Study On Synthetical Preservation Technology Of Razor Clams (Sinonovaculla Constricta (Lamark))

Razor clams(Sinonovaculla Constricta) is one of the China's four major cultured shellfish.With its plump and crisp meat,sweet taste, significant drug efficacy,it is very popular with the Chinese.But the shell of Razor clams(Sinonovaculla Constricta) is very thin and brittle,it is vulnerable to spoilage.So it has become an urgent task to extend the shelf-life and expand its sales circulation further.In view of these situations,a study on Synthetical Preservation Technology of Razor Clams(Sinonovaculla Constricta(Lamark)) was done in this paper.Based the basic study of Sinonovacula,the total number of colonies,pH,TVB-N,lactic acid content,color and sensual score,and other indicators in different temperatures and different MAP models were studied to evaluate shelf-life and physical states,with a view to provide a theoretical basis and technical reference for the controlled atmosphere technology preservation of Sinonovacula and other shellfish.The basic nutritional components and ecological ice temperature were analyzed firstly,and then the fresh-keeping effects in different temperatures were researched.This study paves the way for research on synthetical preservation technology of Sinonovacula constricta.The effects of ice temperature preservation in the conditions of eco-region 2℃and different atmosphere component were researched. Integrated indicators such as the TAC,lactic acid,TVB-N,pH and sensory score,chromatic aberration score during storage were studied, and then determined the self-life of Sinonovaculla Constricta in different conditions.Finally,the effects of ultra-high pressure technology used in Sinonovaculla Constricta preservation with modified atmosphere technology were compared in this paper.The results were concluded as follows:1.Sinonovaculla Constricta is a typical low-fat high-protein food, the crude protein content accounted for 9.90%,ash 2.06%,the lowest fat content about 0.573%in fresh Sinonovaculla Constricta.It's Nutrient-rich because of containing all kinds of amino acids.There are high contains essential amino acid,accounting for about 33.10%of total amino acids.Meanwhile,Glutamic acid and aspartic acid have fresh flavor,accounting for about 14%and 9.19%of total amino acids.Glycine and alanine have sweet flavor,accounting for about 6.39%and 12.27%of total amino acids.Therefore,the essential amino acids adding other 4 flavor amino acids account for 41.85%of total amino acids.The ecological ice temperature of Sinonovaculla Constricta is 2.7～2.4℃ that found in this paper,which was the base of the subsequent study of using the Modified atmosphere packaging technology and ecological ice temperature to preserve Sinonovaculla Constricta synthetically.2.According to the criterion of the national seafood,1gTAC＜7, TVB-N＜15mg/100g are the acceptability range and 2^nd criterion of fresh flavor.The study on the preservation effect of different temperature showed that the impact of temperature for preservation effect was significant.The shelf-life of Sinonovaculla Constricta was 4 days under 10℃,and 8-10 days under 0℃.There was a certain degree of relevance between the changes of TAC and TVB-N,and pH and lactic acid over time.The error existed because of using only one indicator, comprehensive using of various indicators will be even better..3.According to the indicators over time and the criterion of the national seafood:1gTAC＜7,TVB-N＜15mg/100g are the acceptability range and 2^nd criterion of fresh flavor and the sensory score＞5,the conclusion shows that the shelf-life of M1,M2,M3,M4,A,VP is 6 days,7 days,8 days,10 days,4 days,4 days.The longest shelf-life increase 150%,compared with the common one.4.CO₂ played a great role in the MAP.25%CO₂ had not obvious effect in the MAP,while the effect of 75%～100%was significant for the preservation of Sinonovaculla Constricta.Vacuum packaging almost didn't have effect in the whole preservation.What's more,the TAC of VP was the greatest of all at the end.It means that adding O₂ in the MAP will have some effects.5.Among ultra-high pressure process,the pressure above 300Mpa played a great role in sterilization.The total number of colonies reduced two or three orders of magnitude,and E.coli had not detected.The conditions of 500Mpa,20℃,15min UHP were the best condition for sterilization.6.There are obvious differences of preservation effect between UHP(500Mpa,20℃,15min) and the common packaging under 4℃.The shelf-life of the common packaging is 4 days,while the shelf-life of UHP (500Mp,20,15min) is 8～9 days.This has similar conclusion,compared with M3 and M4.Therefore,UHP has opened up a new way for the preservation of aquatic products.