Effect Of Different Ages On Tenderness Of Cherry Valley Ducks Breast During Postmortem Aging

This experiment to select15healthy Cherry Valley ducks for the study material, dividedinto three groups by ages (20day-age,50day-age,170day-age). This research focused on thechanges of tenderness of different day-age cherry valley duck meat during postmortemaging.The macro-quality, protease activity, and proteomic changes of different ages wereresearched during postmortem aging. At the same time, key proteolytic enzymes activity aswell as key cytoskeletal protein degradation in the application SPSS16.0analysis ofvariance.And exploring the differences among the macro-quality, key proteolytic enzymesand key cytoskeletal proteins. And the50-day-old ducks for further analysis, calpain inducerof CaCl2and inhibitor MDL-28170treatment the post-mortem ducks, after the treatment,through the measurement of the difference of critical protease activity and the key skeletonproteins degradation amount between the treatment groups and the control group, to study therole of proteases in improving the quality of duck.The main results were as follows:1. The influence of feeding ages on the meat tenderness.During the postmortem agingprocess, the shear force values of20-day-old group was significantly less than50days oldand170days old group, the difference was significant (P <0.01), the difference in pHbetween the different ages groups were significantly (P <0.05),20-day-old group pH valuewas significantly higher than50days and170days of age (P <0.05). Drip loss and cookingloss of the three-day-old groups reached its maximum at24h,50days old cooking loss wassignificantly higher than the20-day-old and170-day-old group (P <0.01), the difference ofMFI values between50-day-old and170-day-old duck was significant (P <0.05). With theincrease of the ages, insoluble collagen content were increased, soluble collagen content andsolubility were decreased; in48hours postmortem, cathepsin-B, calpain, caspase-3activity,and Tropnin-T and desmin degradation products of20-day-old group were significantlyhigher than the other two-day-old groups (P <0.05).2. The influence of postmortem aging time on the meat tenderness. During thepostmortem aging process, the pH value first decreased and then rebounded to reach aminimum at96h, in110h,20-day-old was significant difference with50days old and170daysold the pH value of the (P <0.05), in24h, the shear force value was significantly decreased (P<0.05).Drip loss of50day-old significantly increased in24hours (P <0.05), cooking loss of the three groups were significantly increased within24hours(P <0.05).MFI reaches amaximum value for24h, followed by a slight decline. As the aging time prolonging, solublecollagen content and the solubility was increase, while the total collagen and insolublecollagen content were maximum at the first day, and then decreased. Cathepsin-B, calpain andcaspase-3activity were decreased significantly with mature extension of time (P <0.05), andthe tropnin-T and desmin degradation products were also a significant increase (P <0.05).Therefore, the post-mortem mature period of time will help to improve the tenderness of theducks.3. The influence of critical protease activity on the meat tenderness. The calpain inducerCaCl2and the inhibitor MDL28170were selected to treat the postmortem ducks, then at4℃matured for a period of time, the results showed that caspase-3activity and Na+K+-ATPaseactivity of CaCl2treatment group were significantly lower than the control group (P <0.05),the activity of cathepsinB, Ca2+-ATPase activity and MFI values significantly higher than thatin the control group (P <0.01),while, the inhibitor MDL28170groups’ caspase-3activity, Na+K+-ATPase activity and Ca2+-ATPase activity were significantly higher (P <0.01),cathepsinB activity and MFI values were significantly lower than the control group (P <0.05).Determination of shear force values, the CaCl2treatment group was significantly lower thanthe control group (P <0.05), the MDL28170treatment group was significantly higher thanthat in the control group (P <0.01), calpain is activated by calcium co-duck tenderness workin collaboration with other protease.4. The influence of key cytoskeletal protein degradation on the meat tenderness. Studieshad shown that the improvement of the quality of meat tenderness was attributed to thedegradation of the protein desmin and troponin-T. The results of this experiment show that thetropnin-T degradation strip strength of CaCl2group was higher than the control group, whilethe strength of MDL28170treated group was lower than the control group; desmin intensityof the bands is higher than that in the control group.