Study On Regulation Of Color And Shear Force Value Of Yak Meat

China is a major producer of yak.Yak meat is rich in protein and various essential amino acids,and it has the characteristics of low calories and low fat,so it is called a natural green food.However,it grows on high altitude,low-oxygen plateaus all year round,so myoglobin content is higher than other meats.Yaks are older when slaughtered,which results in darker meat,thicker muscle fibers,and poor tenderness.At present,there are some problems in the color protection and tenderization technology of meat products,which will affect the quality of meat products to a certain extent.In this study,the longest muscles of yak dorsal from different ages were selected as the research objects.The effects of these two factors on the color characteristics of yak meat were investigated by adding chlorine salt and shaking the treatment.After the tenderization of yak meat by vibration technology,the phase difference microscope,stereomicroscope,transmission electron microscope,scanning electron microscope,and protein electrophoresis were used to observe and analyze the muscle fiber structure,myofibrillar protein,and hydrolysis.This provides a theoretical basis for the development and utilization of yak meat,and provides a certain scientific basis for the industrial application and subsequent research of vibration technology in future meat products.The specific test content and results are shown below.Effects of chloride salt concentration and shaker time on yak color characteristics and cooking loss.A two-factor and three-level factorial experimental was designed to study the effects of chloride salt concentration and shaker time on the color difference,porphyrin iron content,and cooking loss of yak meat.Studies have shown that the chloride salt concentration and shaker time have significant effects on the brightness value L*,porphyrin iron content and cooking loss(P<0.05),and the shaker time also significantly affects the redness value a*.In summary,when the three chloride salt concentrations are all 3%and the shaking time is 1 h,the redness value a*is the smallest.The color of the yak meat obtained by this method is the best.Effect of vibration on shear force value of yak meat.Under the condition of constant amplitude,the vibration time,vibration frequency,material-liquid ratio,and different ages were used as test variables to study the shear force values,myofibrillation index(MFI),and ultrastructure of yak meat.The research shows that the vibration time of 2 h,the vibration frequency of 40 Hz,and the material-liquid ratio of 1:1 are the optimal vibration condition combination.Under these conditions,the shear force values of the longest muscles of the yak dorsal longus muscles in the 6-7 year old age group and 9 years old and above significantly decreased.Observed through a microscope,the tissue structure was more loose,and the space between muscle fibers was more obvious.And the MFI value gradually increased,compared with the control group,both increased about 2 times.There was no significant difference in MFI between 6-7 years old and 9 years old and above after vibration treatment(P>0.05).Effects of vibration on yak muscle fibril structure and hydrolysis.Based on the experimental results in Chapter 3,the structure and hydrolysis of yak dorsal long muscle muscle fibrils were observed using electron microscopy and protein gel electrophoresis.Studies have shown that the vibration treatment increases the spacing between muscle fibers,and the rows are loosely arranged,the myofibrils are arranged disorderly,and the Z line tends to break.However,the auxiliary salt treatment will seriously damage the myofibril structure and the Z line is almost completely broken.During the vibration treatment,the myofibril protein was partially hydrolyzed,the troponin T hydrolysis was more obvious.The salt-added vibration treatment has a significant hydrolysis effect,most of troponin T and actin are hydrolyzed,and myosin is completely hydrolyzed.