Quality Change And Control Of Sturgeon In Cold Chain Logistics

In this study,hybrid sturgeon was used as raw material to study the changes in the cold sturgeon,frozen sturgeon,and modified atmosphere sturgeon during cold chain logistics transportation,and to determine the optimal transport mode and temperature of sturgeon cold chain transportation,for aquatic products cold chain logistics development and preservation methods provide a reference basis.First,refrigerated cold chain logistics?storage 1d-transport 1d-storage 1d-transport 1d-marketing 9d?and at 25?of air temperature was simulated,during which three modes of three temp.fluctuation?logistics 1,complete cold chain logistics at 4?;logistics 2,two transport processed were exposed to 25?;logistics 3 last transport was exposed to 25??.Results showed the shear force of sturgeon during logistics is decreasing,with value of2309.7,1585.4,1751.4,respectively after sale.L value increased first and then decreased,reaching the maximum value of 59.8,57.8 and 59.1 after 3d,and decreased to 53.9,49.3 and51.9 respectively after sale.TVB-N value were 13.1mg/100g,17.9mg/100g,15.7mg/100g and TBARS were 0.88mg/kg,0.93mg/kg and 0.93mg/kg,respectively;Total plate count reached the limit of 10⁶CFU/g respectively on 13d,7d and 10d,respectively.All results showed complete cold chain logistics guaranteed the best freshness and longest shelf life of sturgeon,the more time of broken-off chain,the lower the fish meat quality.Second,the results of quality changes of frozen sturgeon during the cold chain transport?logistics 1,complete cold chain logistics and sale at-18?;logistics 2,two intermittent-3°C chain-broken logistics;logistics 3,two intermittent-3°C chain-broken logistics and broken chain sale;logistics 4,consecutive three-3°C chain-broken logistics and broken chain sale,detailed logistics plan is show in 3.3?,inspect fish quality changes.Results showed the four logistics of the sturgeon meat have a downward trend with time both in the hardness and shear force.Compared with logistics 1,the decline trend of logistics 2,3,and 4 is significant,while the most fluctuating temperature decline most.After the end of the 38th day,the fish meat pH value dropped to 6.07,5,81,5.89,5.86,respectively;the TVB-N value was 8.12mg/100g,8.75 mg/100g,9.52 mg/100g,9.8 mg/100g,respectively;the TBARS value reached0.72 mg/kg,1.58 mg/kg,2.04 mg/kg,1.64 mg/kg,respectively.The temperature is always standard logistics 1 of water holding capacity and the cooking loss rate remains stable,however,due to the tempertuare fluctuation of the transportation process,logistics 2,3,4 of the water holding capacity was continuously reduced,and the cooking loss rate continued to increas.Compared with the relative to the ice sales logistics 3,frozen sales logistics 2 can keep the meat quality of meat,and transportation environment tempertuare fluctuations of the most frequently logistics 3,small variations in its value.The above results show that the quality of sturgeon meat which is always at a stable low temperature?-20°C?complete cold chain logistics is the best,and the more frequent the temperature fluctuation,the more significant the fish meat quality declines.Further study on the lipid oxidation status of fish meat during the transport process of temperature-changing logistics 3 showed that the content of monounsaturated fatty acids in fresh sturgeon meat was high,with the highest oleic acid content,accounting for 34.47%of the total fatty acid content.The acid and free fatty acid contents of sturgeon meat during the cold chain transportation process of logistics 3 not only increased,but also the phospholipid content decreased.After the storage period ended,the acid and free fatty acids increased by6.26mg/g and 0.44%,respectively.The above results show that multiple changes in temperature have a great influence on lipid oxidation in fish.Third,the studies of air conditioning packing and pretreatment?package1,air-packed for the control group;package 2,modified atmosphere packaging filled with 70%CO₂+30%N₂gas ratio;package 3,soaking for 2min with 0.2%acetic acid and packing of gas with70%CO₂+30%N₂ gas ratio was added?on the quality of sturgeon meat in cold logistics.Results showed 70%CO₂+30%N₂ packaging compared with air package,the modified atmosphere package can well inhibit the increase of TVB-N,TBARS,K value and the total number of colonies,and change the species of bacterial.After immersed in 0.2%acetic acid for 2 min,the pH value decreased from the initial 6.71 to 6.21,and the total number of colonies decreased from 3.71 lg?CFU/g?to 2.64 lg?CFU/g?,indicating that acetic acid has a good bactericidal effect.The TVB-N value of packing 1 sturgeon rose fastest and the value was 14.35mg/100g at 7d,which was close to the upper limit of first-order fresh value15mg/100g,the values of packaging 2 and 3 reached 14.12mg/100g and 13.0mg/100g respectively at the end of the 19d logistics,and did not exceed the first grade freshness value.After 19d,the total number of fish colonies in the three packages was 8.74,7.67,and 5.62lgCFU/g,respectively.The main predominant bacteria in all three kinds of packaged fish were Acinetobacter spp.,acetic acid mainly inhibited the growth of Acinetobacter spp.After19 days,the dominant bacteria in the three packaged fish were Pseudomonas spp.,Carnobacterium spp.and Carnobacterium spp..All results showed modified atmosphere packaging and combination with acetic acid pretreatment are beneficial to slow down the decline of quality of sturgeon during the process of cold chain logistics.