| 1.Oyster is a warm water bivalve shellfish,oyster is also the fourth greatest farming economy shellfish of our country.Oyster was broad farming in the coastal areas and the production was gradually rising. Oyster is delicious and nutious,but it was easy be infection by microbial and lose eat value,it couldn't be stored in freezing temperature and have a peculiar smell of fish,these affect it's value can't be fully realised.Therefore,it is necessary to improve the conventional processing,disttribution and storage process to produce a oyster produt that have a weak smell of fish and a longer shelf life.Oystrea rivularis is the raw material of this study,the smell of fish was reduced by blanching and vacuum method,while make the oyster initial cure.The storaged condition was treated by hurdle technology to avoid the deterioration of oyster and nutrition lose.The physicial and chemical indicators were analysised during the oyster storaged,and estibilished a mode of the shelf life to predict the shelf life of the oyster during the storaged.The main contents and conclusions were as follows:Using the method of blanching and vacuum to make the oyster meat deodorization and preliminary cure.The blanching temperature,time and vacuum degree were selected in single-factor expeiments,on this basis to make the neural network optimization.The experimental results showed that the order of influence on deodorization was time >vacuum degree > temperature within the range of experiment.The best condition was temperature of 80?,time 3min,vacuum was 0.07 MPa.HS-SPME-GC-MS was used to analysis the voliatile components of the fresh oyster meat and after deodorization,the results showed that the main smell of fish were:Limonere,Hexanal,Heptanal,Octanal,2-Octenal,Benzaldehyde,2-Nonenal,1-penten-3-ol,1-octen-3-ol,(Z)-1,5-oct-diene-3-ol,2-octen-3-ol,2,4-decadiene and2-octene-1-alcohol,after deodorization,the fishy ingredients of oyster reduced 3.99%, the odor removal rate reached 20.8%,while the flavor of oyster meat after blanching increased.Oyster was blanching and vacuum deodorization at differdent conditions will losssome weight,the rate of weight loss increses with time and temperature,but the degree of vacuum have no significant effect.The results showed that the initial cure process mainly affected by temperature and time,the vacuum was not significant.2. In the hurdle technoly processing of oyster meat,the concention of NaCl,pH and nature pressivative were secleted as single factors,after single-factor experiments,the results showed that when the concentration of NaCl was 4%,pH was 3.5,the microorganism was better inhibited.Based on single-factor experiments of different natural pressive,make neural network optimization,the results showed when the concentration of Nisin,lysozyme and tea polyphenols respectly was 0.348g/Kg,0.044%,0.03%,temperature was 10?,the growth of micribial could be better inhibited.3.The low temperatur oyster meat quality parameters was compared with related national standards,the results showed the product in line of the targets.The quality changes of the oyster meat stored at low temperature was measured,the results showed that compared with control,the product of the indicators were better than control.The predicitive model(SL=7.71×10-11?exp(7132.33/T))for shelf-life based on APC was eatablished to predict the shelf-life of the oyster meat stored at low temperature.The result showed that the shelf-life of the oyster meat stored in 0~10? could be better predicted by the predictive model,when the temperature were 0,4 and 10?,the shelf-life of the low temperature oyster meat were 17.1,11.7 and 6.8d. |
PDF Full Text Request