Study On Technology Of Keeping Alive And Preservation Of Freshwater Fishes

The research object in this paper is freshwater fishes. First,this study is about the keeping alive technology of the artificial cultivation crucian carp which is under the without water and with alittle water conditions in ecological freezing temperature,and the biochemical changes during the keeping alive process.Second, used of different freezing point regulator to lower the freezing point of crucian carp and common carp and research the preservation test of crucian carp and common carp under frozen and high humidity conditions. Finally, a preliminary study of the quality changes of common carp under frozen storage conditions.Firstly,the research is about the keeping alive technology in ecological freezing temperature of the artificial cultivation crucian carp, by studying the critical dormancy temperature identified the range of ecology freezing temperature of crucian carp,then though the studying on the impact of temperature,oxygen supply, gradient cooling rate and the use of anaesthetic to the survival time without water preliminary identified survival process without water of crucian carp. The results showed that:at 25℃add 40 mg / L of the MS-222 then slow cooling to the critical temperature of crucian carp, then under 3-5℃pure oxygen conditions of crucian carp can survival without water for 30 h.As survival time without water is to short to transportation so consider about adding a little amount of water to extend the survival time of crucian carp. The final choice is in the beginning of slow cooling adding 38 mg·l-1 of MS-222, after the slow gradient cooling use water to fish weight ratio of 2:3 add ice water , and finally in the 3 ~ 5℃oxygenation conditions to keep alive crucian carp as a better process.In the course of the keeping alive the basic chemical composition of crucian carp unchanged, changes in amino acids, with the keep-alive time to extend the trend of increase in lactic acid increased gradually, before 60 hthe survival rate of carp for 100%, 70 h for 97 %, 80 h reduced to around 67 %.Secondly,selects the artificial cultivation crucian carp and common carp as research object instudy of freezing and high humidity processing technology,through used of different freezing point regulator and complex to lower the freezing point of crucian carp and common carp to get a wider range of freezing regional.The experimental results show that: when sorbitol content is 1.78 %, calcium chloride content is 2.99 %, sodium chloride content is 1.41 % t the freezing point of the crucian crap block down to -1.6℃; when sorbitol content is 1.5 %, calcium chloride content is 1 %, sucrose leachate content is 0.5 % t the freezing point of the common crap block down to -1.7℃.Used in the vacuum injection method make freezing point regulator faster access to the fish muscle,the results showed that vacuum handling 20 min and 15 min the freezing point of crucian carp block and common crap block reseach the scheduled freezing point value,and through the determination of the elasticity fish muscles that vacuum handling impacts is little.Thirdly, make a preservation box which is under freezing point temperature and humidity condition,then doing the preservation comparison test of crucian carp and common carp under 0 ~ -1℃and humidity of 95 % condition and frozen condition.Assessed the sensory quality and determined the total number of bacteria, TVB-N values of fish during the preservation.The results showed that:Under freezing point temperature, after about 20 d the freezing point regulation crucian carp and common carp are in the secondary freshness standards. Finally, a preliminary study of the quality changes of common carp plating ice clothes and not plating under frozen storage conditions,the results showed that plated ice can prevent water evaporation and sublimation of internal body,and can prevent the temperature fluctuations which have impact on fish,clothing deal with the crossing ice fish have a certain advantage of storage.