Enzymic starch-degrading ability of meat and blood plasma in products after processing

Abstract

The starch-degrading activity of beef muscles, commercial beef and pork cuts and of bovine blood plasma was studied. Beef sirloin and shoulder cuts were shown to contain enzymes capable of degrading starch. The activity corresponded to an increase in reducing equivalent of about 400–600 μequiv per 100 g fat free muscle per minute. In the commercial meat cuts, the starch-degrading activity of pork was higher than that of beef. In bovine blood plasma and potato flour mixtures starch degradation was observed in samples that were heated and subsequently stored. The most extended starch degradation was found in samples heated to 60°C prior to storage. In meat sausages the maximum starch degradation during storage was obtained when samples were heated to 70°C. The increase in reducing equivalents during 7 days' storage at 6°C corresponded to the hydrolysis of about one-third of the starch content of the sausage. Most of the increase in the reducing ability was detectable as glucose, indicating that a major part of the enzymic starch degradation resulted in free glucose. No decrease in the overall number of glucose equivalents was observed in the meat sausages during storage. The implication of starch degradation for the textural quality of sausages is discussed.