The objectives of this study were to evaluate the extent marbling compensates for reduced beef palatability at elevated degrees of doneness and to determine the relationship of residual moisture and fat in cooked steaks to beef palatability, specifically beef juiciness. Paired strip loins (IMPS # 180) were collected to equally represent five quality treatments [Prime, Top Choice (modest and moderate marbling), Low Choice, Select, and Select Enhanced (110% of raw weight)]. Steaks were grouped into sets of three consecutively cut steaks and randomly assigned a degree of doneness (DOD): very-rare (VR; 55 °C), rare (R; 60 °C), medium-rare (MR; 63 °C), medium (M; 71 °C), well done (WD; 77 °C), or very well done (VWD; 82 °C). Samples were subjected to consumer and trained sensory evaluation, Warner-Braztler shear force (WBSF), slice shear force (SSF), pressed juice percentage (PJP) evaluation, and raw and cooked proximate analysis. There were no (P > 0.05) quality treatment × DOD interactions for consumer sensory ratings, indicating increased DOD had the same negative impact regardless of marbling level. There was a quality treatment × DOD interaction (P < 0.05) for the percentage of steaks rated acceptable by consumers for juiciness. Increased marbling modified the point in which steaks became unacceptable for juiciness. Similarly, there was a quality treatment × DOD interaction (P < 0.05) for trained juiciness ratings. When cooked to MR and lower, Prime was rated only 8% to 18% higher (P < 0.05) than Select for trained juiciness ratings, but was rated 38% to 123% higher (P < 0.05) than Select when cooked to M and higher. Besides cooking loss, combined cooked moisture and fat percentage was more highly associated (P < 0.01) to consumer juiciness (r = 0.69) and trained initial (r = 0.84) and sustained (r = 0.85) juiciness ratings than all other objective evaluations. Using regression analyses, cooked moisture and fat percentages, alone, were poor indicators of consumer and trained juiciness ratings. However, when combined, the regression equations explained 45%, 74%, and 69% of the variation in consumer, trained initial, and trained sustained juiciness ratings, respectively. These results indicate that increased marbling levels only offer "insurance" for juiciness of steaks that are cooked to high degrees of doneness, but not for other palatability traits. Additionally, cooked residual moisture and fat percentages, when combined, are a good indicator of sensory juiciness ratings.

The objective of this study was to evaluate the impact of marbling level in combination with enhancement on beef palatability when strip loin steaks were cooked to 3 degrees of doneness. Consumer and trained sensory panelists evaluated strip steak palatability traits of 3 USDA quality grades: Prime, Low Choice, and Low Select. Additional strip loins from each grade were enhanced to 108% with a water, salt, and alkaline phosphate solution. Steaks from each treatment were cooked to 3 degrees of doneness (DOD; Rare: 60°C, Medium: 71°C, or Very Well-Done: 82°C). Consumer panelists rated all enhanced treatments similar (P > 0.05) for each palatability trait. Enhanced steaks had greater (P < 0.05) juiciness, tenderness, flavor liking, and overall liking ratings than all non-enhanced treatments, regardless of grade. Consumer juiciness, tenderness, and overall liking scores increased (P < 0.05) as DOD decreased. Trained sensory panelists rated all enhanced treatments similar (P > 0.05) for initial and sustained juiciness, myofibrillar tenderness, and overall tenderness and greater (P < 0.05) than all non-enhanced treatments, other than non-enhanced Prime, for the same traits. Trained sensory panel ratings increased (P < 0.05) as DOD decreased for sustained juiciness, and both myofibrillar and overall tenderness. Moreover, Warner-Bratzler shear force values were similar (P > 0.05) among all enhanced treatments, and lower (P < 0.05) than non-enhanced Low Choice and Low Select treatments. Results from this study indicate marbling level has no impact on the palatability traits of enhanced strip loin steaks. Therefore, enhancement of higher valued, high marbled cuts does not provide additional palatability benefits over low marbled cuts, as enhancement does not provide an additive effect with marbling on beef eating quality.

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Abstract:The objective of this study was to evaluate the effects of marbling texture on consumer and trained sensory panel ratings of beef strip loin steaks from 3 USDA quality grades. Beef strip loins (n = 117) were selected from 3 quality grades [Top Choice (Modest 00 -Moderate 100 marbling), Low Choice (Small 00 -Small 100 marbling), and Select (Slight 00 -Slight 100 marbling)] to equally represent three different marbling texture groups: fine, medium, and coarse, via visual appraisal. There were no quality grade × texture interactions (P > 0.05) for all of the traits evaluated. Consumers (n = 104) rated all marbling texture groups similar (P > 0.05) for tenderness, juiciness, flavor, and overall liking, as well as rated a similar (P > 0.05) percentage of samples from each marbling texture group acceptable for each palatability trait. Moreover, consumers indicated no preference (P > 0.05) among marbling texture groups for visual desirability or likelihood to purchase. However, trained sensory panelists rated coarse marbled steaks higher (P < 0.05) than fine or medium marbled steaks for both beef flavor intensity and sustained juiciness, as well as higher (P < 0.05) for initial juiciness than medium textured steaks. There were no differences (P > 0.05) among marbling texture groups for Warner-Bratzler shear force, slice shear force, and pressed juice percentage. Low Choice steaks were rated higher (P < 0.05) than Select steaks by consumers for tenderness, flavor liking, and overall liking, but similar (P > 0.05) to Top Choice. Results from this study indicate marbling texture had no impact on consumer evaluations of eating quality and only minimal effects on trained sensory panel palatability ratings and therefore provides no palatability-based evidence for the exclusion of coarse marbled carcasses from current and future branded beef programs.

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