Experimental Study On The Effects Of Different Sterilization Processes And Packaging Techniques On The Storage Quality Of Spiced Beef

Spiced beef has always been loved by consumers due to its abundant nutrition and good taste.Spiced beef is a kind of traditional Chinese food with a shelf life of about 4 days in bulk,thus it fails to spread widely because of its short shelf life,inconvenient packaging and difficult storage.The growth and reproduction of microorganisms is the main cause of meat spoilage,so inhibiting the growth of microorganisms and enzyme activity is essential to prolong the preservation period of meat products.Therefore,study on the green and safe preservation technology of meat products is of great significance.In the present work,spiced beef is employed as raw material to study the effects of different packaging methods and low temperature plasma,irradiation,and ultra-high pressure sterilization technology on its storage quality.We determine the optimal preservation method,and provide theoretical basis and important reference for green preservation of spiced beef.1.As shown in studies on storage quality of spiced beef in different packaging methods,compared with air packaging and vacuum packaging,modified atmosphere packaging can inhibit the growth of microorganisms,slow down the lipid oxidation,and keep the color stability of samples better at 4℃.Among the five modified atmosphere packaging,the optimal parameter is 75% CO2 + 25% N2.Increasing CO2 ratio properly shows certain controlling effect on lipid oxidation with no obvious effect on the color of spiced beef,thus can extend the shelf life of spiced beef effectively.In conclusion,the shelf life of air-packed spiced beef is 4 days;the shelf life of vacuum-packed spiced beef is 6 days which is relatively extended by 2 days;the shelf life of 75% CO2 + 25% N2 packaged spiced beef can reach 8 days which is relatively extended by 4 days.2.As shown in the low temperature plasma single factor test and response surface optimization test,the sterilization effect is significant with low temperature plasma treatment power of 350~450 W and treatment time of 3~7 minutes,and no obvious negative effect on the freshness of spiced beef is observed.The optimal parameters of low temperature plasma are treatment time of 5 min,treatment power of405 W,and the total number of colonies can reach 1.45 log CFU/g.In conclusion,thepreservation effect of plasma modified atmosphere packaging group is better than that of plasma vacuum packaging group;the shelf life of plasma vacuum packaging group samples is 15 days;the shelf life of plasma modified atmosphere packaging group samples can reach 16 days.3.As shown in studies on the effect of irradiation treatment on the storage quality of spiced beef,the storage quality of spiced beef in vacuum and modified atmosphere packaging with different irradiation doses show great differences.The sterilization effect of irradiation treatment on vacuum packaging samples is more significant,and the preservation effect at 4℃ is better than modified atmosphere packaging samples.Different doses of irradiation treatment increase the L* and b*values and decrease the a* value of samples during the initial storage,and cause different degrees of oxidation of protein and lipid.Sterilization effect enhance with the increase of irradiation dose.As the dose is over 6 k Gy,obvious unacceptable radiation odor appears.In conclusion,the quality of vacuum-packed and modified atmosphere packaged spiced beef is better under 4~6 k Gy irradiation;compared with the unsterilized group,vacuum-packed group shows better storage quality under 6k Gy irradiation with a shelf life of 13 days;modified atmosphere packaged group shows better storage quality under 4 k Gy irradiation with a shelf life of 12 days.4.As shown in ultra-high pressure single factor test and response surface optimization test,the sterilization effect is significant with the pressure of 200~300MPa and processing time of 10~20 min.The original quality of spiced beef can be maintained with no obvious influence on its sensory score,TVB-N and p H.The optimal process parameters for ultra-high pressure are a pressure of 247 MPa,a treatment time of 15 min and the total number of colonies can reach 1.78 log CFU/g.In conclusion,the shelf life of ultra-high pressure vacuum packaging group is 11 days,while that of modified atmosphere packaging group can reach 13 days.The comparison and analysis of different sterilization processes show that the order of preservation effect of the three sterilization methods is low temperature plasma,ultra-high pressure,and irradiation.Low temperature plasma sterilization technology shows significant sterilization effect with no obvious influence on the quality of spiced beef.The shelf life of spiced beef in modified atmosphere packaging with low temperature plasma can be extended to 16 days.