Effects of high pressure combined with thermal treatment on myoglobin in pork

The effects of high pressure(0.1~600 MPa) combined with thermal treatment(25~55 ℃) on myoglobin(Mb) and color in pork and their relativity were investigated in this article. The results showed that the L* and△E values,and the total amount of Mb increased but a* value decreased,the colour of pork changed from red to grey-white with the increase of temperature and pressure. Temperature had almost no influence on the contents of Mb,deoxymyoglobin(Deoxy Mb),oxymyoglobin(Mb O2) and metmyoglobin(Met Mb)(p>0.05) when pressure was not present. The content of Deoxy Mb gradually rose with increase of temperature under the condition of 100 ~ 300 MPa but showed a trend of first increasing and later decreasing( p < 0. 05) with the pressure 400~600 MPa. Under any pressure condition,the content of MbO_2 gradually decreased with increase of temperature( 25~45 ℃), but it decreased sharply when temperature was up to 55 ℃( p <0.01). Met Mb increased( p < 0. 05) with increase of pressure when the temperature was constant. It decreased with the increase of temperature when the pressure was 100,200 and 600 MPa. The effects of pressure and temperature on colour and Mb redox state had strong interrelationship. Four optimal multinomial regression models between color parameters and various forms of Mb were obtained and they had higher significance(p <0.05),which suggested that colour was used to predict the contents of Mb and its main existing forms.