The three main palatability characteristics of beef are flavor, tenderness and juiciness (Savell 1987, Lyford 2010, McBee 1967), with tenderness and juiciness being primarily physical properties. Noticeable differences in tenderness and juiciness occur after cooking, and there are numerous studies to support the effects cooked degree of doneness (DOD) and marbling have on all three palatability characteristics (Lorenzen et al., 1999; Campion, Crouse, & Dikeman 1975). During cooking, heat changes beef through moisture loss, fat migration and protein degradation (Jones et al., 1992). Moisture and fat transfer heat differently (Cross 2006), but the impact of beef composition or quality grade on beef thermal properties are currently unclear. This project was conducted to establish a baseline of the physical and thermal properties of raw beef steaks within different quality grades.
Tests to evaluate the physical and thermal properties of different raw beef strip steaks from USDA Prime, Low Choice and Standard grades were conducted at 39°F. Texture was evaluated through measurements for tenderness, chewiness, hardness, resilience and springiness were collected. Meanwhile, steak thermal dynamics (heat transfer behavior) and protein degradation were measured. The primary proteins measured in this study were the contractile proteins of myosin and actin, as well as the proteins found within the sarcoplasm. Of all the measurements collected, four were determined to have statistical differences: hardness, resilience, springiness and the degradation of myosin and sarcoplasmic proteins.