Development Of Green Fresh-keeping Agent And Research Of Preservation Technology On Carassius Auratus Fillet

Carassius auratus fillet was tender,and had high nutritional value,it was easy to be rotten during storage period,which affected the carassius auratus fillets' edible value and nutritional value.Effect of three kinds of biological preservatives on the carassius auratus fillets under refrigeration including tea polyphenols,nisin,citric acid were examined.The optical concentration ratio of different biological fresh-keeping agents were optimized by using the way of the response surface design,The carassius auratus fillets were analyzed for microbiological,physical and chemical index.Further,controlled atmosphere packaging were combined under refrigeration condition,and the change of the carassius auratus fillets'quality under different concentrations of gas condition were studied in order to set up the comprehensive preservation combined with controlled atmosphere packaging technology to improve the quality of the carassius auratus fillet under refrigeration.The main results were as follows:First of all,the optimal concentration range of thefresh-keeping agents were examined.At 4?,tea polyphenols,nisin,citric acid could improve the colour and lustre?hardness and elasticity,making the total number of bacteria,TVB-N and pH value,maintaining good sensory characteristics and improving the edible value of the fillets in comparison to other treatments.As a single biological fresh-keeping agent,the best addition of the tea polyphenols,nisin,citric acid was 1.5%-2.5%,0.3%-0.5%,and 6-10g/L respectively.In addition,the optimal concentration ratio of composite biological fresh-keeping agent using a box-behnken design experiment were evaluated.The concentration of tea polyphenols,nisin,citric acid chosen as the test factors and the TVB-N value was chosen as the target parameter.The best concentration of tea polyphenols,nisin,citric acid were 2.0%,0.4%,8g/L respectively.The composite biological fresh-keeping agent could significantly inhibit the lipid oxidation of the carassius auratus fillets.After 18d of storage,the total number of bacteriawere 5.841g(cfu/g),and keeping the freshness of the carassius auratus fillets.Again,the effect of controlled atmosphere package on the quality of fillets were analyzed,the composition of gas including O2,CO2 and N2,in which it had a direct effect of preservation of the carassius auratus fillet betwwen the concentration of O2 and CO2,N2 played the role of filling.The effect of different concentration gas on freshness of the carassius auratus fillets under the condition of 4? were compared.Finally the preservation effect of the 65%CO2 + 10%O2+25%N2 was the optical candition,where it can be stored for at least 12d.Finally,the effect of biological preservatives combined with controlled atmosphere packaging on the carassius auratus fillets were evaluated.According to results,it found that the concentration ratio of the gas and the compound biological fresh-keeping agent played an important role in the preservation of the carassius auratus fillet.Under the treatment of 2.0%tea polyphenols+ 2.0%Nisin + 8g/L citric acid combined with 65%CO2+10%O2+25%N2,the shelf-life of the carassius auratus fillets in refrigerated condition could be significantly extendeded.The results of this study are a useful way for the development of new commercial applications in the carassius auratus fillets processing and other aquatic research because of its antimicrobial and fresh-keeping characteristics.