The Influence Of Heat Change Of Connective Tissue On Beef Tenderness

According to the Chinese eating habits,beef is usually heated long time before eaten,heating can change the physical property of meat,making beef easier to be digested,and at the same time ensuring the meat safety.Connective tissue properties played a key role in the beef quality,the heating temperature and heating time will ultimately affect the beef tenderness,collagen in the heating process has a series of changes,such as degeneration,dissolving and gelation,although these phenomenon are well known,but how those changes precisely affact beef tenderness still unknown.The heating process of this research involving different heating temperature and time can fully reflect the change of beef connective tissue and meat quality.To examine the correlation of tenderness factors of beef,factors such as shear force,cooking loss,moisture content,texture characteristics,collagen content and thermal solubility,and cross-link concentration of collagen were investigated on beef.Scanning electron microscope images of the cooked beef were also examined.The change of beef quality and connective tissue properties are obtained.The results illustrate how the change of connective tissue properties eventually forming the ultimate beef quality.Beef shear force related to its geometry structure,this study also explores how the connective tissue and muscle fibers affect beef shear force under different muscle fiber directions.The main results are as follows:(1)This study explores the effect of collagen properties on the tenderness of the beef which had been heated to different center temperatures(60-100?).The results showed that soluble collagen and collagen content of dissolved degeneration largely affect the tenderness.As the center temperature rises,the integrity of the perimysial membrane is disrupted,shearing force and chewiness decreased.The increase of collagen content,thermal solubility,and relative content of covalent crosslinks result in the increase of beef elasticity and stickiness.Beef shear force,springiness and chewiness were constitutes the edible quality of beef.Therefore,heating beef to the central temperature of 100?,the beef consumption quality improved.(2)Compared with the heating temperature,the heating time is more significant for the improvement of the ultimate tenderness of beef.Results for the shear force experiment showed that as heating temperature and time increased,shear force significantly decreased.Adhesion was increased,and chewiness,cohesiveness and resilience were decreased.Beef tenderness was significantly correlated with collagen content,thermal solubility,hydroxylysylepyridinoline,cooking loss,moisture content,hardness,adhesiveness,resilience and chewiness(p<0.05).The adhesion and elastic properties of muscles were significantly correlated with covalent crosslinking(p<0.05),and the thermal solubility of collagen has no relationship with covalent crosslinking.The results from our investigations showed that tenderness characteristics of beef were largely dependent on heating time and collagen properties.A longer heating time resulted in an increased effect collagen had on tenderness of beef.The collagen content and amount of covalent cross-linking improved the texture of the meat such as elasticity which improved tenderness.(3)Different direction of muscle fibers(parallel or vertical to the direction of the muscle fibers)has a significant influence on the tenderness of beef,and this section explores the reasons of the difference in tenderness between the muscle fibers and the connective tissue.The results show that the shear force,connective tissue mechanical strength,hardness and chewiness in perpendicular direction were significantly higher than the parallel direction.Shear force was significantly positive correlated(p<0.05)with connective tissue,chewiness,mechanical strength,hardness and adhesiveness in vertical direction.Shear force was significantly positive correlated(p<0.01)with springness,hardness,cohesiveness,chewiness and resilience in parallel direction,and negatively correlated with connective tissue mechanical strength(p<0.05).It is concluded that the tenderness characteristic in vertical direction is determined by the muscle fiber and connective tissue,and the tenderness in parallel direction is determined by a small number of connective tissue and muscle fibers.