| Beef and its products have the advantages of high protein content and variety amino acid,loved by consumers at home and abroad.However,due to its biological composition,beef represents a favorable environment for microbial growth and is highly susceptible to spoilage during the cold storage.In this paper,in order to keep the chilled beef storage quality,prolong its shelf life,the chilled beef was uesd as the research object.The study was about the effects of technology of color-protecting,bacteria-reducing and oxidation-resistance on the color,microbial flora and other physical and chemical indicators of chilled beef for providing a new technical method of fresh-keeping,quality control and shelf life extension.The main research results and conclusions are as follows:?1?The influence of 100%N2?control?and 50%,100%CO pretreatment to the quality of chilled beef during the storage of 4?was studied.The results showed:under the CO pretreatment for 1.5 h,the a*values?red?were significantly higher than the control group?100%N2??p<0.05?,and the relative contents of metmyoglobin were significantly lower than the control group?100%N2??p<0.05?.But the results of total bacterial count,myofibril protein sulfhydryl,metmyoglobin reductase activity and myofibril protein Ca2+-ATPase activity of 50%and 100%CO pretreatment were no significant difference?p>0.05?,compared with the control group 100%N2.There was no significant difference between 50%CO and 100%CO?p>0.05?.?2?The influence of pretreated by different volume percent of CO and O3?100%CO,2%O3+98%CO,5%O3+95%CO,10%O3+90%CO?to the quality of chilled beef during the storage was studied.The results showed:for the groups pretreated by CO,in the the middle and later periods of storage,the surface color a*values and sensory scores were significant higher than the control group CK?p<0.05?,but the drip loss,total bacterial count,pH,the relative contents of metmyoglobin,thiobarbituric acid reactive substance?TBA?and total volatile basic nitrogen?TVB-N?were significantly lower than CK?p<0.05?.The preservation effects of the groups pretreated by O3,especial 5%O3+95%CO,were significant better than 100%CO.Under the storage condition of 0?,the shelf life of chilled beef with the 5%O3+95%CO pretreatment was 46 d,and the shelf life prolonged 12 d than the control group.?3?The effect of exogenous glutathione?GSH?with the mixture gases of CO and O3 on the quality of chilled beef under the storage condition of 8?was studied.The colour,total volatile basic nitrogen?TVB-N?,pH,thiobarbituric acid?TBA?and the total bacterial count were observed.The results showed:the a*value,TVB-N values,TBA values and total bacterial count of the beef treated with 100 mg/L glutathione and mixture gases were significant better than the control group and mixed gases treatment groups.Compared with mixture gases and control groups,the shelf life of beef treated with 100 mg/L glutathione and mixture prolonged 3d and 9d,respectively.?4?The influence of varieties?lactic acid,citric acid,oxalic acid?,concentration?2%,4%,8%?of acids and time?10,30,60 min?to the activation effect of ClO2 and the influence of total bacterial count,TBA value and ClO2 residues of the beef treated by the solution after activation were studied.We could know the influence of the total bacterial count to the detection indicators was the most important through the new repolarization difference test?SSR?on the same factors between different levels of significance test analysis,followed by TBA value,ClO2 residues and the content of ClO2.Comprehensive consideration on this basis,4%citric acid activation for 10 min was optimum.In addition,the influence of beef treated by different time?3,5,10,20,40,80,160 min?and different concentrations of ClO2 solution?20,50,100,150,200mg/L?to the a*values,total bacterial count,TBA values and ClO2 residues were studied.The effect of reducing bacteria were no longer increased significantly when the processing time exceed 10 min,and the ClO2 residues of treated beef were no longer increased significantly when the processing time exceed 20 min.But the TBA values increased with extension processing time.The effect of bactericidal were no longer increased significantly when the ClO2 concentration reached more than 50mg/L,but the TBA values and ClO2 residues increased with increasing concentration of ClO2.Therefore,ClO2 concentration of 50 mg/L and the processing time of 10 min were suitable.?5?The influence treated by O3 water?0.5,1.0,1.5 mg/L?for different time?5,10,15,20 min?to the ClO2 effect of bactericidal was studied.The results showed:O3water combined with ClO2 solution had a obvious bactericidal effect,including the lactobacillus,brochothix thermosphacta,pseudomonas and e.coli.The bactericidal effect of O3 water combined with ClO2 solution was better when the O3 water concentration was 1.0 mg/L and the processing time was 10 min.Meanwhile,the influence of treated by lactic acid,O3 water and ClO2 solution to the total bacterial count and TBA values of beef were studied.We found that spraied by lactic acid could effectively reduce bacteria of the beef treated by O3 water and ClO2 solution,and there were no significant effects on TBA values.In addtion,the influence of CO?ClO2and lactic acid to the quality of chilled beef under the storage condition of 4?was studied.The a*values of every treatment groups were significantly higher than CK?p<0.05?,and the TBA value,total bacterial count,TVB-N values and relative contents of metmyoglobin of CO+ClO2 and CO+ClO2+L were significantly lower than CK and CO?p<0.05?.The preservation effect of CO+ClO2+L was significantly better than CO+ClO2. |
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