Effects of processing variables and storage on the physical, chemical, and microbial characteristics of restructured beef steaks

Production of restructured beef steaks allows utilization of lower cost raw materials to produce higher quality, lower cost products for consumers and more profitable products for processors. The effects of flaking temperature, flake size, mixing time, and storage on this type of product were studied. Semimembranosis, Semitendinosis, and Biceps femoris muscles were obtained from U.S. Commercial and Utility cow carcasses. Muscles were trimmed of external fat and ground through a 2.54 cm plate, mixed 2 minutes, divided in half and tempered to -2.2C or 4.4C. Meat was flaked to produce 1.27 and 1.93 cm flakes. Three batches of meat from each temperature were formulated to contain 100% 1.27 cm flakes, 50% 1.27 cm and 50% 1.93 cm flakes, and 100% 1.93 cm flakes. Mixing times of 10 and 20 minutes were applied to each batch. Three steaks from each batch were allotted to each of 3 storage times of 0, 10, or 20 days at 3.3C. This study was completed in duplicate.

The color of steaks was affected by storage and flaking temperature. Hunter color values a and b decreased with storage time. Also, steaks flaked at -2.2C had higher Hunter L values.

Cooking losses were affected by flaking temperature, mixing time, and storage time. Steaks formed from meat flaked at 4.4C had lower non-volatile cooking loss. Batches mixed for 10 minutes had lower volatile cooking loss. Steaks stored for 20 days had the highest volatile cooking loss while those stored for 0 days had the highest non-volatile cooking loss.

Oxidation, measured by TBA numbers, was affected by flaking temperature. The steaks formed from meat tempered to 4.4C had lower TBA values. Also,steaks stored 0 days had lower TBA values than steaks stored 20.

Mixing time affected proximate composition as steaks formed after 20 minutes of mixing had higher raw moisture. Flaking temperature of 4.4C also resulted in higher raw moisture. Steaks stored for 0 days had the highest water holding capacity, and were the hardest.

Microbial counts were influenced by flake size. Aerobic plate count (APC), lactic acid bacteria count (LAB), and psychrotrophic plate count (PPC) all increased with increased flake size. The highest counts for each type were recorded after 0 days of storage. LAB and PPC increased with increased mixing time. All counts decreased over storage.