Effect Of Delay Chilling And Electrical Stimulation On Beef Quality And The Degradation Of The Myofibril Skeletal Protein

Tenderness is the most important factor to determine the beef quality. Tenderness degree is determining the quality and price of the beef to a certain extent. Because of the frim beef, the development of the beef industry has been restricted greatly, especially in domestic. Nowadays, the inconsistency and variability of beef tenderness are two major problems that meat industry face. To solve the problems, we must deeply understand the mechanism and their tender mechanism to produce the meat variability. Studies have suggested the postmortem treatments (the rate of cooling, electrical stimulation or not etc.) were important factors on beef tenderness. In order to improve the rigor-induced tough, four group crossbreed yellow-bull were butchered according to the standard processing with DC, ES, ESDC and CK treatment. Then the cooking loss, shear force, MFI were analyzed; and the samples were carried on micro-analysis through SDS-PAGE and Western blotting, to explore the tender mechanism of beef. The result revealed:1. With the extension of aging time, MFI value increased gradually. Compared with CK, all treatments had prominent difference (P<0.05), but DC had no obvious difference (P>0.05) at 10 d. After 24h cooling, the ES, DC, and ESDC had no significant effect with each other (P>0.05). At 3d and 7d, there were prominent differences (P<0.05) in four groups, especially, the MFI value of the ESDC treatment was higher than that of the rest. The effects of ES and ESDC were both better than DC treament. At 10 d, the MFI value of ES and ESDC were notably higher than CK (P<0.05), but that of each other was prominently different.However, the difference between DC and CK group was insignificant (P>0.05).2. With the extension of aging time, the shearing force of beef was reduced. At 1, 3, 7 d, the effect of delay chilling on beef tenderness were prominent (P<0.05), but at 10 d, no prominent difference (P>0.05) from CK. The electrical stimulation treatment had significant effects on beef tenderness (P<0.05) at 1, 3, 7, 10 d. The effect of ESDC treatment on beef tenderness was more significant than that of delay chilling or electrical stimulation (P<0.05).3. The MFI value had a better correlation with the shear force in 10 days, and can predict the tenderness of beef. 4. The degradation of the skeletal protein was analyzed by SDS-PAGE and Western blotting.The results suggested that the delay chilling and electrical stimulation notably accelerated skeletal protein degradation both at pace and quantity, shortening the ageing time. In the earlier aging time, the effect of delay chilling was superior to the electrical stimulation, but that of the electrical stimulation was better in the later aging time. The effect of ESDC was better than others, which indicated that electrical stimulation was closely related with cool procedure, and proved that electrical stimulation and delay chilling had cooperative effect on skeletal protein degradation. ES is one of fast aging technologies of meat, and is better with delay chilling treatment.5. Through the degradation situation of skeletal protein and beef quality analysis, it has suggested that other factors may participate in beef tenderness course.