Effects Of Sous-Vide On The Eating Quality And Protein Digestibility Of Braised Pork

Braised pork is a popular meat product in China,but its various processing methods include high-temperature and long-term hot processing steps.Excessive processing methods cause not only damage to the appearance of meat products,but also physical and chemical characteristics,and the bioavailability of nutrients has an adverse effect.With the upgrading of consumption concepts,consumers expect more healthy,nutritious,and safe food.The low-temperature slow cooking(Sous-vide,SV)process uses lower temperatures to cook meat for a more extended period.This method has gradually become the development trend of the food industry.The combination of production makes it possible to produce foods that are both delicious and nutritious.However,the application of SV method started relatively late in China,and the use of SV methods for Chinese traditional meat thermal processing is even more scarce.In this topic,we will measure the moisture content,thermal processing loss,fat content,particle size,and other indicators to get a preliminary understanding of the sensory characteristics of braised pork produced by traditional and SV.We are using SDS-PAGE and Transmission Electron Microscopy(TEM)to explore the differences in protein molecular weight and ultra-microstructure of braised pork under different processes.Using in-vitro simulated protein digestion and Raman spectroscopy to explore the effects of different processes on protein digestibility of braised pork,and find out how different processing methods affect braised pork effects of in vitro digestion of meat proteins on the degree of protein oxidation and changes in its secondary structure.A two-factor three-level experiment was used to explore the quality change of low-temperature slow-cooked braised pork under different temperature combinations.1 Effect of SV thermal processing on edible quality of braised porkThe moisture content of different groups of braised pork was measured with a halogen moisture analyzer.The results showed that the SV group except for the 70?-12 h(SV6)and 75?-12 h(SV9)groups has a significantly higher water content than the traditional processing(CT)group(P<0.05),indicating that the SV process can dramatically increase the moisture content of the product and make the product appear juicy mouthfeel.The 70?-12 h(SV6)and 75?-12 h(SV9)groups undergo 12 hours of long-term treatment,and the gel network in the meat undergoes thermal denaturation to reduce water holding capacity.The shear force under different temperature groups in the SV process varies with the heating time all show a trend of rising first and then decreasing,which is closely related to the contraction and degeneration of protein and connective tissue in meat;the fat content decreases with the increase of heating temperature at the same time,and at the same temperature.The temperature decreases with the increase in heating time,and the trend of fat loss are the same as the trend of thermal processing loss.Analysis of color difference shows that SV thermal processing can make the braised pork uniformly in the same process as the traditional process,and it can also give the meat color higher brightness,showing a transparent and translucent color.From the analysis of the integrity of the sarcomere,it can be found that the bright bands in the traditional processing(CT)group increased,and the dark bands shortened.This may be caused by excessive contraction of myosin and actin by high temperature and long-term heating.Transitional heating may also cause muscle Over-oxidation of fibrils causes the breakdown of myofibril structures and incomplete sarcomere mechanism,which is also the reason for the higher shear force in the traditional processing(CT)group than in the other two groups.Comparing the 65?-8 h(SV1)group and the 75?-12 h(SV9)group,it can be found that the connection between the Z lines of the 75?-12 h(SV9)group is weakened,which indicates that the more intense thermal processing conditions under the SV thermal proces lead to bigger protein structure changes.However,the denaturation intensity is still lower than that of the traditional processing(CT)group.Particle size data indicates that high-temperature stewing may cause excessive aggregation of protein and increase protein particle size,which may create irregular curls and intertwining caused by severe oxidation of the protein due to excessive heating.2 Effect of SV thermal processing on nutritional characteristics of braised porkThe particle size results showed that the Dx(10)and Dx(50)values of the traditional processing(CT)group after digestion with gastric enzymes and trypsin were significantly higher than those of other groups,which may be due to the excessive denaturation and aggregation of proteins caused by high temperature stewing,which reduced the digestive enzymes.The digestibility of the traditional processing(CT)and 75?-12 h(SV9)groups after pepsin digestion was significantly lower than in other groups,and the digestibility of the 65?-8 h(SV1)group was significantly higher than in other groups(P<0.05).After the two-step digestion of pepsin and trypsin,the SV1 group was still considerably higher than the other groups(P<0.05).This may be because the heating conditions at low temperature and short time caused moderate denaturation and aggregation of the protein and increased the contact position with pepsin point.The MDA value showed that the value of the traditional processing(CT)group was significantly higher than(P<0.05)all the SV groups,which indicates that the increase in thermal processing intensity will reduce the MDA value.The SV group also shows apparent regularity.At the same temperature,the MDA value of braised pork increased with the increase of heating time;the ?-helix structure of the traditional processing(CT)group was significantly higher than(P<0.05)the low-temperature slow-cooking group,and the?-sheet content was considerably lower than(P<0.05)SV group,which indicates that the high-temperature and long-term heating caused excessive aggregation of protein structure and caused an increase in the content of the ?-helical structure.