Study On The Preservation Technology Of Chilled Beef And Marinated Beef

The beef tastes good.Eating beef can be benefit to qi,spleen,stomach and bones.Beef is rich in protein,and its amino acid composition is closer to the needs of the human body than pork.However,at present,the development and utilization of beef products in China are still relatively limited.Therefore,this research uses beef as raw material,crude extract of vine tea as natural bio-preservative,the irradiation as sterilization,study on the effect of crude extract of vine tea on the quality of chilled beef during cold storage time,furthermore,the research also study on the effect of the irradiation on the spiced beef,which can provide experimental data and theoretical support for the development and application of beef products.The first part of the thesis was based on the research of vine tea,and the preparation of crude extract of vine tea was studied.The antibacterial activity of crude extract of vine tea against Staphylococcus aureus and Escherichia coli were studied as well.In the inhibition zone experiment,when the crude extract of vine tea was 5 mg/hole,the crude extract of vine tea had antibacterial activity against Escherichia coli and Staphylococcus aureus.However,the crude extract of vine tea had different antibacterial effects against Escherichia coli and Staphylococcus aureus,and had a better antibacterial effect against Staphylococcus aureus.The diameter of the inhibition zone against Staphylococcus aureus was 18.9 ± 1.4 mm.In addition,the MIC values of crude extracts of vine tea against Escherichia coli and Staphylococcus aureus were determined by micro-broth dilution method,and the MIC values were 10 mg/mL and 5 mg/mL,separately.In the second part of the paper,the crude extract of vine tea was added as a natural preservative to chilled beef.The pH,the juice loss rate,the hardness,L*,a*,TVB-N,TBARS,and the total number of microbial colonies of chilled beef during storage for 12 days were studied.At 4 °C,in 12-day cold storage period,the study found that by adding the crude extract of vine tea to chilled beef,the pH value of chilled beef in each experimental group increased,.Comparing with blank control group and solvent,the pH of the chilled beef in the treatment group increased more slowly during storage.(2)With the prolongation of storage time,the juice loss rate of chilled beef in each experimental group showed an upward trend,and by adding 40 mg/mL of crude extract of vine tea as preservative can significantly reduced the juice loss rate of the chilled beef during storage.(3)During the cold storage period,the total number of microbial colonies of chilled beef in each experimental group showed an upward trend,and the total number of microbial colonies in the T20 and T40 treated groups were always lower than that in the untreated blank group and the solvent control group.(4)With the extension of the cold storage period,the hardness values of each experimental group showed a downward trend.During the whole storage period,the hardness values of chilled beef in the T20 and T40 treated groups were higher than those in the untreated blank group and the solvent control group,indicating that by adding 20 mg/mL and 40 mg/mL of the crude extract of vine tea can keep chilled beef with good texture properties during storage.(5)With the prolongation of storage time,the L* of chilled beef in each experimental group gradually increased,while the a* decreased firstly and then increased.(6)The total volatile basic nitrogen(TVB-N)content of chilled beef increased during the whole cold storage period,and the total volatile basic nitrogen(TVB-N)content of chilled beef in T20 and T40 treated groups were always lower than the untreated blank group and the solvent control group,indicating that the crude extract of vine tea could effectively inhibit the increase of the total volatile basic nitrogen(TVB-N)content in the chilled beef.(7)The TBARS values of the experimental treatment groups increased in the storage time,but the TBARS values of the chilled beef in the T20 and T40 treated groups were lower than the untreated blank group and the solvent control group during the whole storage time.Moreover,the increase rate of TBARS value in the experimental group was faster than that in the early stage of cold storage.In the third part of the thesis,the spiced beef was stored in 90 days after treatment with 60Co-?-rays at different irradiation doses of 0,3,6,and 12 kGy.The experimental results showed that after treatment with different irradiation doses,the spiced beef had different degrees of degradation on the nitrite in the spiced beef,and it also showed a dependence on the irradiation dose.With the increase of irradiation dose,the degradation rate of nitrite in spiced beef increased gradually.The peroxide value,moisture content,hardness value,color and sensory score of the spiced beef treated with 3 kGy irradiation dose were not significantly different from those of the unirradiated spiced beef,and the total number of microbial colonies and peroxide values of spiced beef after irradiation were within the national standard during the storage period of 90 days.All of the results provide data and theoretical support for the application of natural bio-preservatives and irradiation in the antisepsis preservation of beef products in China.