| Sauced beef has a unique characteristic flavor and a long history.It is a typical representative of the most traditional Chinese meat products in China and is widely loved by the people.However,the sauced beef is prone to deterioration and rancidity and oxidative deterioration,resulted can’t be preserved for a long time,which limits the industrial production of the sauced beef and restricts its modernization process.At present,the traditional oxidation control technology for sauced beef were mainly by lowering the temperature,adding antioxidants and vacuum packaging to achieve the process of delaying or inhibiting the oxidation reaction,and to some extent,it can achieve the effect of delaying fat oxidation in these ways,but the effect is not very obvious,which is far from the demand of industrialization.Therefore,it is imperative to study the fat oxidation control process of sauced beef and to construct the fat oxidation control theory of sauced beef.In this study,it innovatively combines the modified atmosphere packaging technology with the storage of sauced beef.The sauced beef as the research object aim at the automatic oxidation process of fat of sauced beef in the three modified atmospheres packaging(low oxygen group:5%O2/95%N2,high carbon dioxide group:70%CO2/30%N2,composite group:5%O2/70%CO2/25%N2),vacuum treatment as the control group,set different storage temperatures(4 ℃,25 ℃,60℃)and storage cycle,by studying the physicochemical properties(pH,TBA,AV,POV),oxidative stability(grease stabilizer)of fat beef,changes in fatty acid content in fat(gas chromatography)and total free radical changes(Electron spin resonance spectroscopy)and other indicators,from macro to micro,discussed the effects of different modified atmosphere packaging on the fat oxidation of sauced beef,revealing the intrinsic relationship between fat oxidation and free radical content,to establish the fat oxidation mechanism under modified atmosphere packaging and provides a theoretical basis for the production of traditional halogen meat products.The main contents and research results of the thesis were as follows:(1)Determination of the pH value,thiobarbituric acid value(TBA),anisidine value(AV),and peroxide value(POV)of sauce beef at 4℃,25℃,and 60 ℃ storage temperature was used to study the effects of three modified atmosphere packaging treatments on the fat oxidation of sauce beef,and the vacuum group was used as a control.The results showed that the three modified atmosphere packaging treatments had certain effects on the pH,TBA,AV and POV value of the sauce beef,and the storage temperature also affected the change of the pH,TBA,AV and POV value.Under the storage conditions of 4 ℃ and 25 ℃,the high carbon dioxide group had a good inhibitory effect on the pH value and TB A value of the sauce beef,while the low oxygen group had a good inhibitory effect on the AV value and POV value.However,under the storage condition of 60℃,compared with the high carbon dioxide group,the hypoxic group and the composite group had a poor inhibitory effect on the increase of the oxidation index of the beef.(2)Under the storage conditions of 4℃ and 25℃,the effects of three modified atmosphere treatments on the oxidation stability of sauce beef were studied.The results showed that by comparing the storage temperature,the induction time of each storage day was higher than the induction time of storage days under storage conditions at 4℃,and the storage temperature of 4℃ was more favorable for delaying the sauce beef.Lipid oxidation improves the oxidative stability of the beef fat.At the same storage temperature,comparing the different packaged processed beef can be concluded,regardless of the storage conditions at 4 ℃ or 25 ℃,in addition to the hypoxic group,other modified atmosphere packaged treatments on the oxidation stability of sauce beef were improved compared to the control group.Among them,the high-carbon dioxide group beef had the best oxidative stability,followed by the composite group,while the hypoxia group had lower oxidation stability than the control group,which promoted the lipid oxidation of the sauce beef and reduced the oxidative stability of the beef.The induction time of lipid stored at 4℃ was higher than that at 25℃.it was indicated that the 4℃ was more favorable for delaying lipid oxidation of sauced beef and also for improving the oxidative stability of sauced beef.At the same storage temperature,regardless of the storage temperature of 4 ℃ or 25 ℃,it was found that the other modified atmosphere package improved the oxidative stability of sauced beef compared with control group except the low oxygen group.Among four group,the oxidative stability of sauced beef in high-carbon dioxide group was best,followed by the composite group,while low oxygen group had lower oxidation stability than the control group,which promoted the lipid oxidation and reduced the oxidative stability of the sauce beef.(3)The effects of three modified atmosphere on the fatty acid composition and content of sauced beef storage at 4℃ and 25℃ were studied.The result showed that there were 19 fatty acids in the sauced beef,including 9 saturated fatty acids and 10 unsaturated fatty acids.The content fatty acids of three highest were C16:0,C18:0,C18:1,and followed by C14.:0,C16:1,C17:0,C18:2,while the contents of other fatty acids were less.The results showed that the change of content of fatty acid of sauced beef showed a similar trend with different atmosphere package.That was,with the increase of storage time,the fatty acid content of sauced beef increased gradually,and reached the maximum at a certain point in time,then began to decline,and the final increased slightly.Different storage temperatures had different effects on the change of fatty acid content in sauced beef.At 4℃,the fatty acid content of sauced beef in different modified atmospheres reached the maximum on the 16th day.While at 25℃,the fatty acid content of the sauced beef in the vacuum group and low oxygen group reached the maximum on the 16th day,and the high carbon dioxide group and the composite group reached the maximum on the 20th day.When the fatty acid content reached the maximum value,the fatty acid content in the three modified atmosphere group all were lower than that of the control group,showed the effects on the fatty acid content of the sauced beef.Among three group,the fatty acid content of the composite group was the least,which had a good effect on delaying the increase of fatty acid content.(4)The effects of three modified atmosphere treatments on the free radical content of sauced beef and the correlation between free radical content of sauce beef and fat oxidation were studied at 60℃.The results showed that there were seven kinds of free radicals causing fat oxidation of the sauced beef,and the magnetic field ranged from 3325 to 3375G.The free radical content of the sauced beef in the low oxygen group and the composite group reached the maximum on the 8th day,while the free radical content of the high carbon dioxide group did not reach the maximum value(or just reached the maximum value)at the storage end point.Among three group,the change of free radical content in the high carbon dioxide group was gentle,and the free radical content was the lowest,which significantly inhibited the increase of free radical content.The low oxygen group slightly promoted the increase of free radical content,while the composite group hindered the free radical content rising,but the effect was not as obvious as the high carbon dioxide group.The correlation analysis result showed that the change of the content of free radicals could well reflect the change of fat oxidation process of the sauced beef,and EPR could be applied to evaluate the fat oxidation process of the sauced beef. |
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