A Comparative Study On The Cooking Tolerance Of Muscle Tissues From Different Sources

In this paper,the physico-chemical changes,myofibril degradation and the microstructure of chicken muscle,beef and skipjack muscle were studied under different heating temperature,time and salted condition.To explore the mechanism of muscle protein changes and its effect on muscle tissue quality under heating and salting conditions.Research content and results are as follows:1.The changes of protein,total thiol and amino acid in chicken,beef and skipjack after heating at 40 ?,60 ?,80 ? and 100 ? for 20 min,40min,60 min,80min,100 min and 120 min were studied.The results showed that the content of protein and the content of myofibrillar protein decreased with the increase of time and temperature,and the content of alkali-soluble protein was increased to a certain extent by the increase of the content of protein in muscle tissue from different sources.The content of alkali-insoluble protein was also decreased.The total thiol content of myofibrils was decreased with the increase of time,but the descending rate was different.Through analyzing the change of total thiol content of myofibrils during heat treatment,?,the analysis of free amino acids in the solution shows that with the time continuously extended,the degree of protein decomposition increased,and the relative decrease in the content of cysteine,indicating that the disulfide bond increased,the degree of protein denaturation increased.2.In order to investigate the boiling tolerance of muscle tissue from different sources,chicken,beef,and skipjack was used as raw materials,to boil at 40 ?,60 ?,80 ?,and 100 ? for 20 min,40 min,60 min,80 min,100 min,and 120 min,respectively.The content and molecular weight distribution of the sarcoplasmic proteins,SDS-PAGE gel electrophoresis,microstructure,and protein secondary structure of myofibrils were studied.The results showed that: The denaturation of chicken and beef sarcoplasmic proteins occurred at 40 ?-60 ?,whereas skipjack at60 ?-80 ?;There were still less than 10 kDa protein in beef cooked 120 min at100 ?,whereas there were not in chicken and skipjack,indicating that the beefexhibited better boiling tolerance;The band of myofibrils in chicken,skipjack,beef were seen in the high molecular weight(200 kDa region)and low molecular weight(45 kDa region).But the band of 200 kDa in chicken,skipjack,and beef degraded at60 ?,40 ? and 80 ?;during cooking at 100 ?,chicken started softening at 100 min,beef 120 min,and skipjack 80 min.Therefore,beef displayed the best boiling tolerance,followed by chicken,skipjack;with the increase of cooking time,?-helix for the three muscles turned to random coil structure,while ?-fold increased.3.The diets containing chicken,beef and skipjack fish were immersed in salt solution at 0,2%,4% and 6%(w / w)respectively for 12 hours and then boiled at40 ?,60 ?,80 ? and 100 ?,for 20 min,40min,60 min,80min,100 min and 120 min.The effects of salt solution concentration on the thermal denaturation of muscle tissue were studied.The results showed that the protein denaturation temperature was decreased with the increase of salt concentration,while the salt solution immersion treatment promoted the degradation of myofibrillar protein in muscle tissue,which made the myofibril fibril structure blurred...