Quality of steak restructured from beef trimmings containing microbial transglutaminase and impacted by freezing and grading by fat level

Objective: The objective of this research was to evaluate the physico-chemical, microbiological and sensorial qualities of restructured steaks processed from beef trimmings (grade I and II) and frozen beef (fresh beef as control and frozen beef). Methods: Beef trimmings from commercial butcher were collected, designated into 4 treatments differing in beef trimmings grade and freezing, processed into restructured steaks with 1% microbial transglutaminase and then analyzed for product quality. Results: The results showed that all meat from different groups could be tightly bound together via cross-linking of myosin heavy chain and actin as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Microbial counts of psychrotrophic and mesophilic bacteria were not affected by treatments (p>0.05), and no detectable of thermophilic bacteria were found. Regarding effect of beef trimmings grade, steaks made from beef trimmings grade II (16.03% fat) showed some superior sensorial qualities including higher tenderness score (p