Studies On The Changes Of Beef Quality In The Processing Of Braised Beef With Potatoes

Braised beef with potatoes,a representative Chinese dish,is popular with consumers because of its flavor and taste.Like other Chinese dishes,braised beef with potatoes owns many problems such as a complicated operation process,unstable product quality et.al..Therefore,the paper was designed to choose the most suitable muscle location for production of braised beef with potatoes,and to investigate the change of eating qualities including tenderness and flavor in the stewing process,which is helpful to supply guidelines to the standardization and industrialization of braised beef production.This study was designed to choose the most suitable muscle for the processing of braised beef by examining differences in the eating quality of braised beef produced from three different muscles: thin flank,chuck roll,and shin-shank.Eating quality was based on analysis of the Warner-Bratzler shear force?WBSF?,texture profile analysis?TPA?,volatile compounds,free amino acids?FAAs?,microstructure,and sensory evaluation of each product.The flavor?according to both volatile compounds and FAAs?of chuck roll was significantly higher than that of the other two muscles,though there was no significant difference in textural properties according to WBSF and TPA among the three braised beef preparations.These observations differ from those based on the raw materials of the three muscles.In addition,chuck roll also received the most votes for consumers' favorite product in sensory evaluation.Our results demonstrate that chuck roll is the most appropriate for the preparation of braised beef.The objective of the study was to investigate the changes of tenderness and water holding capacity and the underlying mechanisms during stewing process of beef muscles by examining cooking loss,Warner-Bratzler shear force,myofibril fragmentation index,differential scanning calorimetry and low field nuclear magnetic resonance.Results showed that with the increasing heating temperature,cooking loss increased significantly.WBSF increased from 55 to 75°C,with two decreased phases from 45 to 55°C and again from 75 to 95°C.Meanwhile,MFI increased first then decreased,with a peak at 65°C,which may be induced by the liberation of actin from actomyosin and contributed to the decreased tenderness at 55°C.Both T₂₁ and A21 of low field nuclear magnetic resonance T2 test decreased significantly decreased significantly at 55⁶5°C,which correlated with the change of cooking loss.These results demonstrated that 55-65°C is a critical temperature during beef stewing process,which could provide a theoretical basis for Chinese braised beef at low temperature.This study was designed to further illuminate the change mechanism of beef eating qualities during stewing process of beef muscles by examining the changes of myofibrillar protein?including myofibril microstructure,degradation of myofibrillar protein and liberation of actin from actomyosin?and collagen?including collagen solubility and microstructure of connective tissue?.Results showed that with increasing heating temperature and heating time,the degree of myofibril shrinkage increased,sarcomere length decreased significantly and the degree of myofibrillar protein degradation increased and produced new bands at 55⁶5°C.Meanwhile,the granulation of connective tissue observed and the collagen solubility increased at 85⁹5°C.The phases of 55⁶5°C and 85⁹5°C are two critical temperature ranges during beef stewing process,which could provide a theoretical basis for Chinese braised beef.This study was designed to investigate the changes of falvor and underlying formation mechanism in the processing of braised beef with potatoes by examining the vol atile flavor compounds,free amino acids content,nucleotide content and equivalent umami concentration of products?including beef,potato and soup?with condiment and without condiment.Results showed that the addition of seasonings can significantly enhance flavor,which contained volatile flavor compounds count and content,free amino acids content,nucleotide content and equivalent umami concentration.In addition,the interaction between potato and beef produced new volatile flavor compounds and increased significantly some free amino acids content.