The Mechanism Of The Influence On Meat Quality Of Goose Muscle Caused By The Generation Of Reactive Oxygen Species (ROS) After Slaughter

There are significant differences in meat quality between the different varieties of geese, andprotein oxidation has a great relationship with its tenderness and Water Holding Capacity (WHC).This study compared the meat quality of five varieties kind of goose including Landaise, Romangoose, East zhejiang white goose, Sichuan white goose and Taihu goose, and studied deeply intothe mechanism for the influence of protein oxidation on the tenderness and WHC.The meat color, drip loss, cooking loss, shear force and pH value of Landaise, Roman goose,East zhejiang white goose, Sichuan white goose and Taihu goose were measured after slaughter0,8,24,48,96h. According to the different demands for different products, different varieties ofgoose are suitable for processing different products in different periods. The meat of Landaise afterpostmortem24h had the best WHC, and the shear force is less than the other varieties within24~48, so it’s applicable to process ham and sausage, which are demand for good WHC andtenderness. Roman goose had the bright red color which changed insignificantly during the wholemature time, but its tenderness was relatively poor than Landaise, so it is suitable for cured meat.East zhejiang white goose meat, Sichuan white goose meat and Taihu goose meat were applicableto shredded meat or drysaltery because of their poor tenderness.Fluorescence probe technology combined with tissue homogenizing was used to determinethe relative content of ROS after slaughter, while Raman spectroscopy was used to determine thechanges of protein structure of myofibril in the natural mature process. Correlation analysisbetween the relative content of ROS, the content of secondary structure and shear force, drip loss,cooking loss showed that ROS promoted α-helix unfolding to β-sheet within8h after slaughter toexposure the hydrophobic amino acid and form cross-linking of protein network, which had anegative impact on tenderness and WHC. The relative content of ROS increased from8h to24hwhile β-sheet transform into β-turn continually. The decrease of β-sheet demonstrated that thedegree of cross-linking between myofibril protein was weakened, which was the reason whytenderness and WHC of meat has been improved during8~24h. After24h, myofibril proteinstructure changed inconspicuously, so the changes in tenderness and WHC may has a relationshipwith the activity of calcium protease and apoptosis enzyme or the damage in protein primarystructure caused by the high concentration of ROS.Raman spectroscopy was used to analyze the structure changes of the myofibrillar proteinsfrom mature geese muscle soaking in hydrogen peroxide (H2O2) solution and N-acetyl cysteine(NAC) solution respectively, including the changes in the conformation of peptide chain and themicroenvironment around the side chain of amino acid. After treating with10mmol H2O2solutionfor.96h, the relative content of ROS was obviously higher than that of NAC treatment group (p<0.05). The content of α-helix decreased significantly (p<0.05) accompanied by β-sheetincreasing significantly (p<0.05) in H2O2treatment group, while the content of α-helix alsodecreased significantly (p<0.05) but random coil increased significantly (p<0.05) in NACtreatment group. In H2O2treatment group, the intensity of main chain of C-C\C-N stretchingvibration was weakened more seriously, indicating that ROS can split the peptide bond andgenerate fragment. The normalized intensity of I760was declined more obviously in H2O2groupand these results suggest that oxidation can enhance the surface hydrophobicity of protein.