Effects Of Modified Atmosphere Packaging Combined With TiO₂ Photocatalysis On Pork Quality During Cold Storage

The packaged chilled pork will be the main trend of meat consumption in China.Meat industry urgently needs effective preservation methods to reduce the risk of microbial contamination and improve product quality and safety.Modified atmosphere packaging（MAP）can prolong the shelf life of fresh products,but its antibacterial effect is limited.TiO₂photocatalysis（TPC）technology has attracted much attention for its ability to inactivate microorganisms and decompose organics,and its application in meat preservation has barely been reported yet.In order to better apply MAP and TPC technologies in the preservation of meat,the present study established a stable gas environment to maintain the freshness of chilled pork and reduce the risk of microbial contamination by adjusting the proportion of gas inside the package and selecting suitable outer packaging films.In present study,further investigation was carried out to explore the synergistic effects of MAP combined with photocatalysis on the freshness and quality of pork during storage.The main research results are as follows:1.Compared with air packaging,the shelf life of pork could be extended for about 8 days by using modified atmospgere packaging,which is able to create a relatively stable internal micro-environmental by adjusting gas ratio and film.Gas ratio of 55%O₂+20%CO₂+25%N₂was more suitable,because it could not only maintain the color of fresh pork but also prevent excessive oxidation.The optimized film material were nylon film and high barrier film both with low gas permeability.The stable internal micro-environment effectively inhibited the microbial growth and TVB-N value rise,which is beneficial to the maintenance of quality.2.The composite package with photocatalytic properties showed the ability of photocatalytic bacteriostasis.With the treatment time increasing,the survival fraction of total viable count and E.coli in pork were decreased.The generated reactive oxygen species（ROS）during photocatalytic process were responsible for inactivation of microbes,but accelerated the lipid oxidation.In order to avoid excessive oxidation,the treatment time of 30 min was more appropriate.Moreover,layer by layer self-assembly was an effective approach to combine nano-TiO₂ with the packaging,and 8 layers loading showed the highest photocatalytic activity.3.The combination of MAP（55%O₂+20%CO₂+25%N₂）with photocatalysis slowed down the process of corruption,and the corruption period delayed for 4 days compared with MAP alone.The combination technique significantly（p<0.05）reduced the total viable count and TVB-N value of pork in the late middle of cold storage.The combination technology showed positive effects on the color,pH and water holding capacity of pork.4.The increase of oxygen content could enhance the generation of ROS during the photocatalytic process,while the opposite effect was obtained by increasing of carbon dioxide content.The combination technology would aggravate the lipid oxidation,but the change of TBA value was not significant in the early storage（p>0.05）.With the increase of storage time,the accumulation of oxidation products was accelerated,causing adverse effect on pork.Modified atmosphere packaging combined with Ti O₂ photocatalysis achieved a synergistic effect on the control of microbial contamination of pork,exhibiting a higher antibacterial capacity,but at the same time it aggravated the lipid oxidation.