Feeding management effect on flavor and selected chemical characteristics of frozen ground beef

Thirty-nine steers were divided into thirteen trios according to breed, body type and weight. One of each trio was finished on pasture (orchard grass and clover, low energy ration), another of each trio was finished on grain but limited (low energy ration) to gain weight at the same rate as pasture-finished, and the other of each trio was finished on unlimited grain (high energy ration). Flavor and selected chemical characteristics of ground beef prepared from the semimembranosis muscle and fat trim of the brisket from the left side of each carcass were determined after 30 and 180 days storage at -18°C. A selected panel of six members consistently scored ground beef from steers finished on pasture approximately 1.3 to 1.4 units lower on a 7 point scale (1 = dislike extremely more than reference to 7 = like extremely more than reference) than ground beef from steers finished on a limited or full grain ration. No differences in flavor scores were found for storage. Ground beef from pasture-finished steers had significantly less free sugars than ground beef from grain-finished steers. Ground beef from low energy ration finished steers had significantly higher free fatty acids and lower quantities of lipid oxidation products than ground beef from high energy ration finished steers. All chemical characteristics (free fatty acids, lipid oxidation products, free amino compounds and free sugars) increased significantly during storage. Fatty acid analysis of neutral lipids and polar lipids of ground beef from steers of Angus breed only (18 animals) showed that pasture finished steers had less palmitic and more stearic and linolenic acid in both neutral and polar lipids than steers finished on limited grain. Ground beef from steers finished on low energy rations had more myristoleic, palmitoleic and stearic acid and less linoleic and linolenic in neutral and polar lipids and more palmitic acid in the neutral lipids than ground beef from steers finished on high energy ration.