Research On The Preservation Of Litopenaeus Vannamei Processed By High Hydrostatic Pressure Combined With CO₂

High hydrostatic pressure?HHP?and dense phase carbon dioxide?DPCD?are two promising non-thermal processing technologies,which are mainly used for microorganism,inactivation,enzyme inactivation and improvement of food quality in the food industry.Although HHP has better inactivation microorganism effect,but less enzyme inactivation effects for some enzymes?for example,polyphenol oxidase,PPO?,and even activate some enzymes?for example,PPO?,which tend to cause food quality decline.Higher pressure and longer time are required to inactive these enzymes,and increases the cost.DPCD has better effect of microorganism and enzyme inactivation,but the high standard sterile shop need to be equipped to package products.If we could make full use of the advantages of HHP and DPCD and make up for their shortcomings each other,it will not only help to improve the effect of microorganism and enzyme inactivation,but also shorten the processing time and reduce the cost.Firstly,the inactivation of PPO from Litopenaeus vannamei was studied by HHP combined with CO₂?HHP + CO₂?.Secondly,Litopenaeus vannamei was treated directly by HHP + CO₂ and the effects of HHP + CO₂ on the melanosis and preservation of Litopenaeus vannamei were studied.Finally,a ready-to-eat P&D Tail on was processed and treated using HHP + CO₂,and storage characters were studied and the shelf life prediction model was established.The results were as follows:?1?For PPO extracted from Litopenaeus vannamei,HHP + CO₂ treatment can inactivate PPO irreversibly.The relative activity of PPO reduced to 18.92 ± 1.52 % by HHP + CO₂ at 100 MPa for 30 min.The relative activity of PPO reduced to 10.91 ± 1.08 % by HHP + CO₂ at 200 MPa for 10 min.The relative activity of PPO reduced to 4.67±1.57% by HHP + CO₂ at 300 MPa for 5 min.The relative activity of PPO reduced to 2.69±1.60% by HHP + CO₂ at 400 MPa for 5 min.PPO was inactivated by 100% at 500 MPa for 10 min.At the same treatment pressure and time,the effect of HHP + CO₂ on the inactivation PPO was significantly better than that of HHP treatment and CO₂ treatment?P <0.05?.?2?The whole shrimps were treated by HHP + CO₂.The treatment at 100 and 300 MPa can prevent shrimps from melanosis to a certain degree,but can not completely prevent them from melanosis.HHP and HHP + CO₂ treatment can make the initial pH value of the shrimp meat increasing because of protein denaturation,so the pH value is not suitable for the evaluation of shrimp meat quality treated by HHP and HHP + CO₂.HHP and HHP + CO₂ treatment at 500 MPa can effectively inhibit the shrimp spoilage.Both HHP and HHP + CO₂ treatments increased the initial hardness and elasticity of shrimp meat,but the hardness of the shrimp meat showed a slight increase and the springness of the shrimp meat changed little with the storage time increasing.?3?From the storage characteristics?Total bacterial count,TVB-N value,Sensory scores?of ready-to-eat P&D Tail on,the inactivation microorganism effect of HHP + CO₂?400 MPa/10min?was better than that of HHP?500 MPa/10min?.The shelf life prediction model was established based on TVB-N value,and the predicted values showed that the developed ready-to-eat P&D Tail on requires refrigeration and cold chain circulation.The ready-to-eat P&D Tail on treated by HHP + CO₂ could be stored at 4 ? for 239 days?about 8 months?,and The ready-to-eat P&D Tail on treated by HHP could be stored at 4 ? for 173 days?about 6 months?.