Off-campus UNL users: To download campus access dissertations, please use the following link to log into our proxy server with your NU ID and password. When you are done browsing please remember to return to this page and log out.
Non-UNL users: Please talk to your librarian about requesting this dissertation through interlibrary loan.
Collagen utilization in whole muscle beef roasts
Beef connective tissue was cooked to 75°C internal temperature in a solution containing water, salt and phosphate with and without the addition of bromelin. Cooked samples were filtered through cheesecloth and the resulting collagen solutions were included in an enhancement brine to inject USDA select grade semitendinosus muscles. Similar roasts pumped with water, salt and phosphates and non-injected samples were used as controls. The first experiment was conducted to determine if the collagen solutions could be injected and to study the effects of the process on yields and quality. A second experiment used Response Surface Methodology to map the effect of injection level and collagen concentration in the brine on yield and quality characteristics of the finished product. All the enhancement solutions were formulated to have the same concentrations of salt and phosphate. ^ Bromelin greatly improved collagen solubility of modified beef sinew and tendons beyond the mere thermal process, and resulted in solutions with higher protein and collagen concentration (P < 0.05). All filtrates adequately gelled at 3°C, and their viscosity was quickly reduced when temperature increased. ^ The enhancement potential of collagen injection was initially evidenced in the first experiment. Color traits of collagen-injected steaks were no different (P < 0.05) from the controls, and bromelin-treated collagen improved flavor and tenderness scores.^ The second study demonstrated that collagen injection reduced (P < 0.05) purge loss of raw samples. Similarly, increasing the levels of bromelin-treated collagen in the brine increased yields during refrigerated storage of the cooked steaks. Lightness and yellowness were affected by increasing collagen concentration, but the effect was slighter if the collagen was proteolyzed with bromelin. Likewise, at lower levels of injection, collagen inclusion resulted in decreased a* values as compared to water, salt and phosphate enhanced roasts. Sensory scores were acceptable for collagen-injected samples regardless of pump level, but were poor in control steaks with less than 15% pump. Tenderness and juiciness improvement was greatly driven by increased moisture retention in collagen-injected samples, as evidenced by a significant correlation between product moisture and sensory traits. ^
Agriculture, Food Science and Technology
Esquivel, Oscar, "Collagen utilization in whole muscle beef roasts" (2004). ETD collection for University of Nebraska - Lincoln. AAI3159541.