Acomyosin Dissociation And Its Effect On Duck Meat

The eating quality of meat is important for customer satisfaction that influences their buying decisions.The eating quality of meat includes tenderness,flavor,color,aroma and juiciness,and among them the most important quality is the tenderness.Therefore,how to improve the tenderness of meat has become growing concern for researchers.Heat treatment is an important means of meat processing,during heating process,the meat proteins are denatured,causing structural changes of muscle fibers,and finally impact on tenderness,meanwhile actomyosin dissociation also occurs in this process.Therefore,we propose that the dissociation of actomyosin has some relevance with improvement of the meat tenderness.To study the factors that contribute to actomyosin dissociation and its relationship with tenderness,in this research,duck meat was used as material,and SDS-PAGE,TPA,Western-blot,TEM,SEM,etc.were carried out.The research will also provide theoretical guidance for the industrial processing of duck meat.Four parts are included in this study,the details are described as follows:1.Heat induced dissociation of actomyosin in duck breast muscleTo illustrate the changes of actomyosin during heating process of duck muscle,duck breast muscle were treated with different heating temperature?45,50,55,60,65,70 ??and heating time?0,1,10,20,30,60 min?.The dissociation of actomyosin was evaluated by western blot analysis of the changes in actin content.Results showed that there was almost no actomyosin dissociation when muscles were heated at 45 ?.With the extension of heating time,the actin content increased at the early stages and then declined when muscles were heated at 50,55,60 ?,but it was significantly higher compared with those in control groups.When heating at 65 ? for 60 min,the actin content decreased to the equal amount as in the control groups;and when heating at 70 ? for 30 and 60min,actin was not detected.The results suggested that actomyosin dissociation was significantly improved when the muscle was heated at the temperature of 50-60 ? and at the time of 1-10 minute.2.Actomyosin dissociation as influenced by Ca²⁺?ATP?ADP and AMPTo understand the potential factors that promote the dissociation of actomyosin,actomyosin was extracted from duck breast muscle and the effect of Ca²⁺,ATP,and its degradation products on actomyosin dissociation was investigated.The dissociation of actomyosin was evaluated by western blot analysis of the changes in actin content.Results showed there was no significant change in actomyosin dissociation when it was treated with 7.5?64 mmol/L Ca²⁺,whereas actomyosin dissociation was enhanced significantly by 200 mmol/L Ca²⁺ treatment.ATP treatment alone did not result in a significant change in actomyosin dissociation,but Ca²⁺ and ATP combined treatment could significantly increase actomyosin dissociation.ADP or AMP promoted actomyosin dissociation remarkably,but there was no significant difference among different concentrations of treatment.The results suggested that actomyosin dissociation was significantly improved when the actomyosin was treated with ADP,AMP,and the combination of Ca²⁺ and ATP.3.The effect of adenosine 5'-monophosphate?AMP?on tenderness,microstructure and chemical-physical index of duck breast meatThe effect of adenosine 5'-monophosphate?AMP?on meat tenderness and other quality traits of duck breast meat was investigated in the present study.Duck breast muscle was treated with 0,10,20,30,40 mM AMP at 50 C for 10 hours and examined for shear force,microstructure,actomyosin dissociation,myofibril fragmentation index?MFI?,pH,water content,cooking loss,CIE*color?L*,a*,b*?,inosine monophosphate?IMP?and free amino acid?FAA?contents.Results showed that shear force,cooking loss,L*and b*of the muscles significantly decreased after AMP treatment;actomyosin dissociation,MFI,pH,water content,fiber diameter,sarcomere length,IMP and ammonia significantly increased;no significant change in a*and other FAA content was observed,and muscle shrinkage in tranversal and longitudinal direction were restrained after AMP treatment.All these results suggest that AMP could notably improve the meat tenderness,and this effect was probably mainly through increasing muscle pH,promoting actomyosin dissociation,and disrupting Z-line,meanwhile the conversion of AMP to IMP improved the flavor of meat.