| Application of high pressure technology in food is more and more widely, and as a kind of cold sterilization technology destroyed less on food nutrition and sensory quality than heat treatment,and application of high pressure in meat products are generally combined with heat treatment to kill microorganisms, but the pressure could promote the intramuscular lipid oxidation of meat, thus reduced the safety of meat products, and lipid oxidaxion was closely related to fatty acid composition and meat color. In order to further explore the reasons of intramuscular fat oxidation under super high pressure, then better control and improve the quality of meat, which is very necessary to system study of the treatment of different pressure and temperature on the changes of pork intramuscular fatty acid composition, color, fat oxidation. Therefore this research takes the white jade black pig as the study object, studying the effect of different pressure combined with different temperature, holding pressure time on composition of intramuscular fatty acid, lipid oxidation and color of pork, and exploring the relationship between color change and fat oxidation. The specific research contents and results are as follows:1.In order to study the effect of different test conditions (200～500 MPa,10-20min and 20～60℃)on the color of pork, the longissimus muscles were used. It is the color parameters redness (a*), yellowness (b*), lightness (L*)and total color difference (△ E),were studied, response surface method(RSM)was applied on the basis on the analysis of the pre experimental results. The results of RSM showed that pressure was the most significant factor for the value of b*,L*, △ E, while temperature was the most significant factor for the value of a*,pressure and temperature had significant (p<0.05) interactive on the value of a* and △ E, and elevating temperature could significantly and linearly decrease the treating pressures influencing the value of a*, while the critical pressures influencing the value of △ E linearly raised with temperature increasing, pressure and holding times had significant (p<0.05) interactive on the value of △ E, and extending holding times could significantly and linearly decrease the treating pressures influencing the value of △ E. As a conclusion, in the conditions of pressure 350MPa,temperature 40℃,holding times 15min,which could not cause significantly changes in color of meat. In order to further explore the reasons of intramuscular fat oxidation under high pressure.2.For investigating the effect of super high pressure combined with thermal treatment on intramuscular lipid oxidation in meat, and exploring the relationship between the color and lipid oxidation of pork in the super high pressure combined with thermal treatment, the longissimus muscles were used, After the treatment of 200-650MPa,20～60℃and 10-20min, the changes of lipid oxidation index and the color of pork were observed. The results showed that pressure, temperature and their combination treatment could accelerate the oxidation of intramuscular fat; it made significant increase in TBARS and acid value under 350MPa and above pressure combined with thermal treatment, and the color of meat was gradually from red to gray. Gaining the correlation between the color parameters and TBARS, acid value by using relevant statistical analysis software, therefore, it could judge the lipid oxidation through the flesh color.3.To study the effect of super high pressure and a certain temperature on fatty acid composition of intramuscular lipid, the longissimus muscles were used. After the treatment of 300-700MPa,20～50℃ and 10-20min, the changes of fatty acid composition of total lipids, triglycerides, phospholipids and free fatty acids were observed. The results showed that pressure was the most significant factor for fatty acid composition of intramuscular lipid, the next was the temperature, the interaction of pressure and temperature was significant, while the effects of holding time was not significant. Changes of fatty acid composition was mainly caused by the phospholipid and free fatty acid in whole processes, but it had a little change in fatty acid composition of intramuscular total lipids and triglycerides; it made significant degradation in phospholipids under 300MPa and above pressure combined with thermal treatment, and the more PUFA degraded resulting in the percentage of PUFA decreased significantly in phospholipids, while the SFA and MUFA increased significantly in phospholipids, moreover, the changes of composition of free fatty acid was contrary to phospholipids. |
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