Hilton G G, Tatum J D, Williams S E, Belk K E, Williams F L, Wise J W, Smith G C
Department of Animal Sciences, Colorado State University, Fort Collins 80523, USA.
J Anim Sci. 1998 Aug;76(8):2094-103. doi: 10.2527/1998.7682094x.
Strip loins from 354 female bovine carcasses, selected to represent 30 skeletal maturity (A, B, C, D, and E) x marbling score (SA/MA/AB, MD, MT, SM, SL, and TR/PD) subclasses, were used to evaluate current and alternative systems for classifying cow carcasses into expected-palatability groups. Strip loins were vacuum-packaged, stored for 14 d postmortem at 2 degrees C, and frozen (-27 degrees C). Five steaks from each strip loin, each cooked to a different internal temperature (60, 66, 71, 77, or 82 degrees C), were used for shear force determinations. Two steaks from each strip loin, one cooked to 66 degrees C and the other to 77 degrees C, were used for sensory evaluation. Increased carcass maturity was associated with decreased tenderness and juiciness, increased flavor intensity, and a higher incidence of flavors described as "painty," "fishy," and "grassy." Position of a carcass within a maturity group had a negligible effect on palatability. Increased marbling was associated with greater tenderness and juiciness, a lower incidence of steaks with a "grassy" flavor, and a higher incidence of steaks with a flavor described as "fatty." Relationships between marbling and beef palatability traits were consistent across all maturity groups. Carcasses of maturities A through E were most effectively stratified according to differences in palatability when marbling scores were grouped as follows: 1) MD and higher; 2) SL, SM, MT; and 3) TR/PD. Among mature (C, D, and E maturity) carcasses, yellow-colored fat was associated with greater beef toughness and higher detection rates for "grassy" and "fishy" flavors. Higher end-point temperatures were associated with higher shear force values and lower ratings for muscle fiber tenderness, connective tissue amount, overall tenderness, and juiciness. Two alternative grading approaches (one involving current quality grading factors and the other involving the use of fat color as an additional grade factor) were developed for possible use in classification of cow carcasses into expected-palatability groups. Both alternative systems provided a more effective stratification of cow carcasses according to palatability differences than did the current USDA quality grading system.
从354头母牛胴体上取下里脊，这些母牛经过挑选，代表30个骨骼成熟度（A、B、C、D和E）×大理石花纹评分（SA/MA/AB、MD、MT、SM、SL以及TR/PD）亚类，用于评估将母牛胴体分类为预期适口性组别的现行和替代系统。里脊真空包装后，在2℃下宰后储存14天，然后冷冻（-27℃）。从每条里脊上取五块牛排，每块牛排烹饪至不同的内部温度（60、66、71、77或82℃），用于测定剪切力。从每条里脊上取两块牛排，一块烹饪至66℃，另一块烹饪至77℃，用于感官评价。胴体成熟度增加与嫩度和多汁性降低、风味强度增加以及被描述为“油漆味”“鱼腥味”和“草腥味”的风味发生率更高有关。胴体在成熟度组内的位置对适口性影响可忽略不计。大理石花纹增加与更高的嫩度和多汁性、“草腥味”牛排发生率降低以及被描述为“脂肪味”的牛排发生率更高有关。在所有成熟度组中，大理石花纹与牛肉适口性特征之间的关系都是一致的。当大理石花纹评分按以下方式分组时，根据适口性差异，A至E成熟度的胴体最有效地分层如下：1）MD及更高；2）SL、SM、MT；3）TR/PD。在成熟（C、D和E成熟度）胴体中，黄色脂肪与更高的牛肉韧性以及“草腥味”和“鱼腥味”的更高检出率有关。更高的终点温度与更高的剪切力值以及肌肉纤维嫩度、结缔组织量、总体嫩度和多汁性的更低评分有关。开发了两种替代分级方法（一种涉及现行质量分级因素，另一种涉及使用脂肪颜色作为额外的分级因素），可能用于将母牛胴体分类为预期适口性组。与现行美国农业部质量分级系统相比，这两种替代系统根据适口性差异对母牛胴体进行了更有效的分层。
