Influence of malic acid marination on characteristics of connective tissue and textural properties of beef Semitendinosus muscle

Semitendinosus muscle marinated in 0.5% acid showed a significant decrease in the shear force. To explore the possible reasons responsible for tenderness of acid-treated beef, the changes in intramuscular connective tissue (IMCT) were taken into consideration. The thicknesses of primary perimysium (PP) and secondary perimysium (SP) decreased to 19.86 and 34.99 mu m, respectively. Denaturations of IMCT were exhibited by decreased onset (To) and peak (Tp) temperature, and by the increase in collagen heat solubility. A significant increase in intensity ratios between 3 and 24 h group (p < 0.05) meant that the dissociation of decorin (DCN) enhanced gradually along with marinating time. Meanwhile, limited transitions between 310-helix, anti aggregated strands, and turn were observed, especially a significant decrease (p < 0.05) in turn. The dissociation of DCN and the changes in second structures could partially contribute to the initial denaturation of collagen and reduce TO and TP, resulting in the decrease in shear force.