EPIMYSIAL CONNECTIVE TISSUE POLYSACCHARIDES OF BOVINE SEMIMEMBRANOSUS MUSCLE AND ALTERATIONS IN THEIR TYPE WITH AGE AND SEX DIFFERENCES

Abstract

ABSTRACT— Newborn veal, 11.5‐month‐old steers, 14.5‐month‐old heifers and 9 to 10.5‐year‐old cows were used to identify the polysaccharide types present in the epimysium and to determine the relationship between the amount of connective tissue polysaccharides and the amount of collagen in the epimysium. Trimmed muscle was used for tenderness evaluation by shear force. Average amounts of 332, 247, 230 and 202 mg dry polysaccharides per 100g dry, defatted epimysium were isolated from the veal, steer, heifer and cow groups, respectively. A negative correlation was obtained between age of animals and amount of isolated polysaccharides. Only 20% of the hexosamine in the dried defatted epimysium was extracted as soluble connective tissue polysaccharides. It is possible that some selective solubilization of certain polysaccharides occurred during extraction and, consequently, the extracted polysaccharides may not reflect the actual polysaccharide composition of the intact tissue. Considering this, it was found by using Dowex 1 x‐2 chromatography that an average of 42% of the total uronic acids of the veal and heifer groups was eluted with 0.5M NaCl. 17 and 19% of the cow and steer uronic acids, respectively, were eluted with 0.5M NaCl. In the veal and heifer groups, 37 and 38% of the total uronic acids were eluted with 1.5M NaCl, whereas in the cow and steer groups the amount represented 71 and 70%. The percentages of uronic acids eluted with 2.0M NaCl were 20, 11, 19 and 12% in the veal, steer, heifer and cow groups, respectively. Dermatan sulfate was found to be the main polysaccharide eluted with 1.5M NaCl for the veal, heifers and cows. It also represented an important type in the steers, although other sulfate polysaccharides seemed to be present. Cellulose polyacetate electrophoresis confirmed that hyaluronic acid and dermatan sulfate were present in the epimysium. The ratio of hexosamine to insoluble collagen in the epimysium was positively associated with muscle tenderness.