The Effects of Thawing Methods on Trained Sensory Evaluation of Beef Palatability Traits and Instrumental Measurements of Quality

Objective:Using beef strip loins steaks, evaluate six common thawing methods and assess the quality attributes through a trained panelist evaluation and an array of instrumental quality measures. Study Description:Paired Low Choice strip loins (n = 15) were collected from a beef packing facility. The paired loins were fabricated into 1-in steaks and blocked into six blocks of four steaks. Each block was assigned a different thawing method, and each steak within the block a test, then aged 21 days and frozen. Thaw methods consisted of the four USDA-approved thaw methods: refrigerator (REF), cold water (CW), microwave (MIC), cooking from frozen (COOK); and two methods commonly used by consumers: countertop (CT) and hot water (HW). Steaks assigned to REF were thawed in a refrigerator at 34–37°F for 24 hours prior to cooking. Steaks assigned to CW were thawed in individual containers of 34–37°F water for 24 hours prior to cooking. COOK steaks were cooked immediately upon removal from the freezer, while still in a frozen state. CT steaks were thawed at ambient temperature (68°F) for 5 hours. HW steaks were thawed in a sous vide machine set to 104°F for 20 minutes (± 2 minutes). MIC steaks were microwaved at 50% power for 3.5 minutes, flipped, and repeated in a retail microwave. Fifteen trained panels were performed, with eight panelists consuming six samples from the same loin. Each steak was cooked to a peak temperature of 160°F on clamshell style grills. Data were analyzed as a completely randomized block design. Results:As a whole, thawing method had a minimal impact on palatability There were no (P>0.05) differences among thawing methods for initial juiciness, sustained juiciness, connective tissue, pressed juice percentage, L*(lightness), lipid oxidation, Warner-Bratzler shear force and slice shear force. For myofibrillar tenderness, COOK steaks were tougher (P<0.05) than REF and CW. Also, MIC and COOK steaks were lower (P<0.05) than CW and REF steaks for overall tenderness, while all other treat­ments were similar (P>0.05). The COOK steaks were rated higher (P<0.05) than all other treatments for beef flavor intensity. The MIC steaks had lower (P<0.05) cooked a* (redness) and b* (yellowness) values than REF, HW, and CW steaks, while CT samples had higher (P<0.05) values than COOK and MIC. The MIC steaks had the highest (P<0.05) cook loss, followed by COOK (P<0.05), with all other treatments being similar (MIC>COOK>CT = HN = CW = REF). MIC and HW had a higher