Sulfated glycosaminoglycans and collagen in two bovine muscles (M-semitendinosus and M-psoas major) differing in texture

M. semitendinosus (ST) and M. psoas major (PM) were used as models for toug h and tender meat to study a possible role of sulfated glycosaminoglycans ( GAGs) for muscle tenderness. The difference in texture was confirmed by War ner Bratzler shear force measurements. No significant difference in total a mount of GAGs in the muscles was found. In contrast, a significant differen ce in the ratio of GAG/collagen was found between the two muscles. After se paration of the GAGs by density gradient ultracentrifugation and ion-exchan ge chromatography, dermatan sulfate (DS), keratan sulfate (KS), chondroitin sulfate (CS), and heparan sulfate (HS) were identified by cellulose acetat e electrophoresis after use of specific enzymes and chemical methods. The c ontent of DS was higher in the tougher muscle (ST) than in PM, and the diff erence in DS content was statistically significant. Furthermore, a signific ant difference in the GAG composition pattern of the two muscles was found. The yield of GAGs extracted from the muscles was 77% for ST and 87% for PM . The residue after extraction was further analyzed and found to contain ma inly HS. Immunohistochemical studies using antibodies against CS/DS showed a staining pattern of the perimysium of ST different from that of PM.