Preservation Technology of Pork in Modified Atmosphere Packaging

At present, the main forms of pork circulation on the market are hot fresh meat, frozen meat, and cold fresh meat, each of which has its own advantages and disadvantages. Hot fresh pork is pork that is slaughtered and sold, but the quality of pork is poor, and safety and hygiene cannot be guaranteed. Its advantages are short circulation time, low circulation cost, and low technical requirements for processing and preservation. The form of pork products; the storage temperature of frozen meat is -18~℃-25℃, its storage time is long, and the shelf life can reach 1 year, which is convenient for circulation, but the quality of frozen meat is poor, the loss of juice is large, and the loss of nutrients is serious; Meat is the main form of pork circulation in developed regions in Europe and America, which can better ensure the quality and nutritional hygiene of pork, and is gradually becoming the main form of pork circulation in the market. However, the shortcoming of chilled meat is the short shelf life, generally below 7d, which seriously restricts the circulation of the product. Therefore, extending the shelf life while maintaining the nutritional quality of pork has become a new hotspot in meat research.

Preliminary research has found that at a slightly freezing temperature (1°C to 2°C lower than the freezing point of pork), pork can not only prolong the shelf life, but also maintain good pork quality.

The paper uses Lanxihua pork as the material, and uses sensory scores, pH, water holding capacity, TVB. N. The total number of bacteria was used as the index. The effects of the micro-freezing technology and the modified atmosphere packaging technology on the preservation of pork were studied, and the two technologies were combined to determine a good pork micro-freezing modified atmosphere packaging technology. The main research contents are as follows:

(1) Research on the preservation technology of pork micro-freezing In this experiment, the preservation effect of pork was compared under three conditions: 4 ℃ refrigeration, -18 ℃ freezing and -2 ℃ micro-freezing. The results showed that the fresh-keeping period of pork refrigerated at 4 ℃ was only about 7 days; the fresh-keeping period of pork frozen at -18 ℃ was long, but the quality of meat decreased after thawing; under the condition of -2 ℃ micro-freezing, the fresh-keeping period of pork could reach 15 days , and can maintain good quality.

(2) Influence of pre-cooling method on the effect of micro-freezing and fresh-keeping of pork This experiment compared the effect of two pre-cooling methods on the effect of micro-freezing and fresh-keeping of pork, direct cooling and rapid cooling (cooling at -18 °C for 1 h and then cooling at -2 °C). The results showed that fast-cooled pork could slow down the spoilage process of pork in the short term, but in the long term, there was no significant difference between the two.

(3) Research on the fresh-keeping technology of pork modified atmosphere packaging In this experiment, the fresh-keeping technology of pork modified atmosphere packaging was studied under the condition of -2℃ micro-freezing. A gas ratio that works well. The results showed that: in the range of 40% concentration, the higher the concentration of CO2, the more obvious the antibacterial effect, but CO2 will also make the meat sour and produce unnatural brown color; 02 can make the pork appear bright red, but it will also accelerate Corruption; through the C02 and O2: combined test results, it is determined that the gas ratio of modified atmosphere packaging for pork under slightly frozen conditions is 40% C02 + 60% O2, and its fresh-keeping period can reach 24 days.

(4) The effect of packaging materials on the fresh-keeping effect of pork slightly frozen modified atmosphere packaging In this experiment, the effect of different barrier properties of packaging materials on the fresh-keeping effect of pork was studied under the conditions of -2℃ slightly frozen and 40%CO2+60%O2 modified atmosphere packaging. influences. The results show that the PET/CPE packaging bags with medium barrier properties have a good preservation effect, and the preservation period can reach 27 days, followed by PE/PA/EVOH/PA/MPE packaging bags with high barrier properties, and PA, ff'E with low barrier properties. The packaging bag has poor fresh-keeping effect.

Based on the above research results, Mingwei Company believes that the best process for the preservation of pork slightly frozen modified atmosphere packaging is: use medium barrier PET/CPE packaging bags for modified atmosphere packaging, the gas ratio is 60%02+40%C02, the packaging is completed Then, it was stored directly under -2°C micro-freezing conditions.