Effects Of Packaging At Mospheres On Shelf-life And Quality Characteristics Of Snowflake Beef Steaks

As the mainstream packaging trend of preservation chilled meat during retail display in the future,modified atmosphere packaging technology(MAP)promotes fresh meat color and protects meat from microbial spoilage.Nowadays,this kind of packaging has developed into a large packaging system which involves complex technology and various types.Highlymarbled fattened cattle,known as snowflake beef in China,are characterized by their ability to deposit a large amount of intramuscular marbling fat.The snowflake beef usually has the most expensive price in markets,however,to our knowledge,few have provided with the information on MAP of snowflake beef.Every year an inappropriate packaging usually results in a huge waste to beef industry.The M.longissimus lumborum were extracted from four fattened cattle(Bos Japanese Black Cattle × Bos Yanbian Yellow cattle)and the lipid content was 22.76%.In the lab,snowflake beef steaks were individually packed in 80%O2 Hi Ox-MAP,or 50%O2 LOx-MAP,or CO-MAP,or vacuum packaging,then placed in a walk-in cooler at 4 ± 1 °C for 12 days.Samples were removed at 0,4,8 and 12 days for microbial and physicochemical analysis.The purpose of this experiment is to investigate the effects of four different commercial packaging conditions on shelf-life and quality characteristics of snowflake beef.In this way,we can explore a suitable packaging which could extend the shelf-life and improve the quality of snowflake beef in actual production.The main results of this study are as follows:(1)p H values showed no significant differences among packaging treatments.Purge loss was significantly higher for meat stored in vacuum packaging compared to the other three packaging.Purge loss of the 80%O2-MAP samples was higher than 50%O2-MAP and COMAP samples.(2)Both packaging methods and storage time had a significant effect on lightness(L*),redness(a*),yellowness(b*),chroma(C*)and hue(h*).Compared with other three packaging types,CO-MAP steaks showed the best color protection effect and had a higher L*?a*?b*?C* than others during display.Although vacuum packaging steaks maintained a lower L*?a*,their color was more stable than aerobic packaging steaks.The 80%O2-MAP and 50%O2-MAP samples had a faster discoloration than anaerobic packaging.50%O2-MAP samples showed the lowest color stability within 12 days and the L*?a* was significantly lower than80%O2-MAP at day 8.The shelf-life of snowflake beef in aerobic packaging should not exceed 8 days due to their metmyoglobin levels have exceeded 40% at day 12.(3)Compared with two aerobic packaging methods used in this study,CO-MAP and vacuum packaging steaks had lower TBA values and carbonyl content during storage,which indicated anaerobic packaging could effectively help reduce the lipid and protein oxidation rate of snowflake beef steaks.80%O2-MAP remained the highest TBA values and carbonyl content that were significantly higher than 50%O2-MAP at day 12.The present study suggests that the shelf-life of snowflake beef in aerobic packaging should not exceed 8 days due to the pronounced lipid oxidation.(4)The CO-MAP and vacuum packaging showed the best microbial inhibitory effect for snowflake beef steaks.50%O2-MAP samples had lower microbial loads compared with 80%O2-MAP.Among these four packaging methods,microbial counts did not reach the recommended legal threshold during the 12-day storage period.(5)It's suggested that adopting anaerobic packaging for snowflake beef.As a realistic alternative for beef industry,CO-MAP had the best preservative effect.If using aerobic packaging for snowflake beef,the shelf-life had better not exceed 8 days.