Study On Superchilling Preservation Combined With Modified Atmosphere Packaging Of Pork

The study is about two important preservation technologies of meat:superchilling and modified atmosphere packaging(MAP). It took Lanxi pigs as experimental material. The indexes included sensory score, pH, water holding capacity, TVB-N and total bacterial count. This study was mainly focused on the following aspects:(1) Research on the superchilling of porkThe preservation effects of pork were compared under conditions of42cold storage,-18℃frozen storage and-2℃superchilling storage. The result showed that the fresh period of pork in4℃was only7days. The pork in-18℃had long fresh period, but it cannot keep good quality. The fresh period of pork in-2℃is as long as15days with good quality.(2) Effects of pre-cooling on the superchilling of porkBefore the superchilling storage of pork, two pre-cooling methods were compared:directly cooling (cooling in-2℃directly) and quickly cooling (cooling in-2℃after cooling in-18℃for1hour). The result showed that pork of quickly cooling can reduce the speed of spoilage in the first few days, but they had no significant difference in the long term.(3) Research on MAP of porkUnder the temperature of-2℃, the roles of CO2and O2in MAP of pork were confirmed. As a result, the best composition of CO2and O2was found. The result showed that more CO2meant the better antibacterial effects in the range of0-40%CO2concentration, but the pork would be sour and brown because of CO2. When O2exists, the pork would keep comfortable colour, but spoilage would be quicker. Finally, the experiment of CO2/O2combination showed that40%CO2+60%O2was the best MAP composition under-2℃.(4) Effects of package material on the MAP of pork in superchilling storageDifferent package material had different barrier property to CO2and O2, which leaded to different effects on pork of MAP storage of40%CO2+60%O2under the temperature of-2℃. The result showed that PET/CPE package with medium barrier property had the best effects, PE/PA/EVOH/PA/MPE package with high barrier property ranked the second, while the effect of PA/PE package with low barrier property was the worst. To summary up, the best preservation process of MAP for pork in superchilling storage is as follows:a. put the pork in the PET/CPE package; b. MAP with60%O2+40%CO2; c. put the package in the temperature of-2℃.