The Effect Of Myoglobin Isolation From Beef Muscle And Lipid Oxidation On Its Stability

During storage beef color will change over time, from bright red to brown, and one of the main factors for this phenomenon is that lipid oxidation, therefore it is important for protecting the color stability from lipid oxidation.The research used fresh longissimus muscle of yellow cattle as raw material, optimize the significant factors, to obtain the best parameters of extraction was studied using response statisticalmethods such as surface analysis, screening some parameters to get the best purification process; identifing the myoglobin and molecular weight; myoglobin after identification was studied on its thermal and pH stability, then puri?ed Mbs were pre-incubated with microsomes and lipid oxidation products to study OxyMb oxidation. This test provides a theoretical basis and reference for further study of the interaction between mtoglobin and lipid oxidation, in addition, provides a theoretical basis for the post-mortem self-protecting color and color stability. The test results are as follows:1. The best extraction and purified parameters of myoglobin were: Optimum parameters were pH8.11, ammonium sulfate concentration was 90.90% and extraction time was 1.59 h. Under this condition, the myoglobin yield was 17.86%. Through screening purification conditions,the Sephadex G-75 was choosed as the main Gel filtration filling, the elution flow rate of 0.3 m L / min, and the volume was 1.5% CV. Under these conditions, the relative purity of 91.74% and the concentration of Mb was 2.43 mg/m L.2. Myoglobin was detected by the wavelength scanning, the results showed that the two curves were basic consistent, and there were two high point in 540 nm and 580 nm wavelength, thus to determine the purified protein is myoglobin. Using SDS-PAGE preliminarily determine molecular weight, the results revealed one band with approximate molecular weights of 17 kDa.3. The influence of external environment: myoglobin was most stable at temperature 4?and pH7.4 by used the wavelength scanning, and measured the myoglobin oxidation state.4. Microsomes were isolation from yellow cattle, and mixed with OxyMb to study OxyMb oxidation. Oxidized microsomes contained higher concentration of TBARS and caused greater metmyoglobin formation than freshly prepared microsomes and control. Freshly prepared microsomes caused greater metmyoglobin formation than control.5. Puri?ed Mb was pre-incubated with lipid oxidation pruducts, as hydrogen peroxide, hexenal and nonenal, the results show that the OxyMb contents of hydroxyl free radical, hexenal and nonenal were reduced 70.60%, 73.57% and 70.65%.These three oxidation products could promote the metmyoglobin formation.