Effects Of Modified Atmosphere Packaging With Different Oxygen-containing On Preservation Effect And Color Stability Of Yak Meat

The yak meat was a kind of natural green food which consumers liked. But, the outdated preservation technologies of yak meat has been the main constraints of this industry, because of the quality of yak meat can not been maintaining well. Recently, the modified atmosphere packaging(MAP) has been one of the popular color-preserving technology for meat. It can prolong the meat’s shelf period to some extent. In this study, the samples of yak meat in vacuum packaging were measured as control group. The experimental group was the MAP with 5 different gas components(O2: 40%-80%; CO2: 20%-60%). The yak longissimus dorsi muscles were packaged with MAP and vacuum packaging, and stored at 0-4 ℃. The indexes of preservation were measured every 4 days and the optimal packaging method for yak meat was. On the basis of above study, the MAP with 3 different gas components(O2: 40%, 60%,80%; CO2: 60%, 40%, 20%) was choosed as the experimental group. The enzymatic and non enzymatic indexes about meat color were measured every 4 days, and the factors affecting meat color stability of yak meat in MAP were explored. The study has provided the theoretical reasons on improving yak meat quality by MAP. The results are as follows:1. During the storage time, the total bacterial counts, TVB-N values and TBA values of yak meat in the MAP, which containing the CO2 more than 40%, were in line with nation standards. In all the packaging groups, the L* values and a* values had the same trends. The L*and a* values in the vacuum packages were low. The yak meat in the MAP of 60%O2 and40%CO2 had high L* and a* values during the hole storage time. Synthesized the effect of preservation and color stability, the package of 60%O2 and 40% CO2 was more suitable to extend the shelf life of yak meat.2. In all the packaging groups, the LDH activity and NADH content had significantly positive correlation with OMb%(P < 0.05), and significantly negative correlation with MMb%(P < 0.05). The MRA activity was insignificantly correlated with a* values and OMb%(P>0.05). LDH activity and NADH content were the main factors effecting color stability.3. In all the packaging groups, the acid values and POV values was insignificantly correlated with the color indexes(P>0.05). TBA values was significantly negative correlated with a* values(P<0.05), and significantly positive correlated with b* values(P<0.01). The end products from lipid oxidation had a negative impact on the color stability.4. In all the packaging groups, the total phenol content, RSA and TEAC was significantly negative correlated with b* values and TBA values(P<0.01). The total phenol content and RSA was significantly positive correlated with OMb%(P<0.01). The authigenic antioxidantsin yak meat had positiv effect on the color stability by controlling lipid oxidation.5. In all the packaging groups, the total phenol content, RSA and TEAC had positive significance correlations(P<0.01). There were synergistic effects among the three indexes,and the total antioxidant capacity of yak meat were improved, therefore, the yak meat could have better color stability.In short, 60%O2 and 40% CO2 was more suitable to extent the shelf life of yak meat. The LDH activity and NADH content was the enzymatic factors which affecting color stability,and the end products from lipid oxidation and the antioxidant substance was the nonenzymatic factors which affecting color stability.