Wulf D M, O'Connor S F, Tatum J D, Smith G C
Department of Animal Sciences, Colorado State University, Fort Collins 80523, USA.
J Anim Sci. 1997 Mar;75(3):684-92. doi: 10.2527/1997.753684x.
This research was conducted to determine whether objective measures of muscle color could be used to classify beef carcasses with respect to tenderness. Bos taurus (161 steers) and Bos indicus cross (101 steers, 55 heifers) cattle were fed a high-concentrate diet and slaughtered in seven groups when ultrasound scans indicated approximately 1.1 cm fat thickness. Following low-voltage electrical stimulation and a 24-h chill, all routine carcass data, USDA grade data, and colorimeter readings (luminance, L*; redness, a*; yellowness, b*) of the exposed longissimus muscle were obtained. The longissimus lumborum was sampled for ultimate pH (pHU) measurement, shear force at 1, 4, 7, 14, 21, and 35 d postmortem, and taste panel assessment at 14 d postmortem. The pHU was correlated (P < .05) with L*, a*, and b* values (r = -.48, -.52, and -.60, respectively). Correlations of color measurements with tenderness measurements were higher than correlations of marbling score with tenderness measurements. Of the three color measurements, b* value showed the highest correlation with shear force value (r = -.38) and taste panel tenderness rating (r = .37). A classification system (lowest 25%, middle 50%, highest 25%) based on marbling score resulted in classes of beef that were 9, 3, and 4% tough, respectively. A classification system (darkest/bluest 25%, middle 50%, lightest/yellowest 25%) based on colorimeter readings resulted in classes of beef that were 15, 3, and 0% tough, respectively. Bos taurus cattle had lower shear force values, higher panel tenderness ratings, higher L* values, and lower a* values (P < .05) than Bos indicus cross cattle.
本研究旨在确定肌肉颜色的客观测量指标是否可用于对牛肉胴体的嫩度进行分类。对161头黄牛和101头婆罗门牛杂交公牛、55头婆罗门牛杂交母牛饲喂高能量日粮，当超声扫描显示脂肪厚度约为1.1厘米时，分7组进行屠宰。经过低电压电刺激和24小时冷却后，获取所有常规胴体数据、美国农业部等级数据以及暴露的背最长肌的色度计读数（亮度，L*；红色度，a*；黄色度，b*）。采集腰大肌样本用于测定宰后最终pH值（pHU）、宰后1、4、7、14、21和35天的剪切力以及宰后14天的感官评定。pHU与L*、a和b值呈显著相关（P <.05）（相关系数分别为-0.48、-0.52和-0.60）。颜色测量指标与嫩度测量指标的相关性高于大理石花纹评分与嫩度测量指标的相关性。在这三项颜色测量指标中，b值与剪切力值（r = -0.38）和感官嫩度评分（r = 0.37）的相关性最高。基于大理石花纹评分的分类系统（最低25%、中间50%、最高25%）得出的牛肉类别中，肉质坚韧的比例分别为9%、3%和4%。基于色度计读数的分类系统（最暗/最蓝25%、中间50%、最亮/最黄25%）得出的牛肉类别中，肉质坚韧的比例分别为15%、3%和0%。与婆罗门牛杂交牛相比，黄牛的剪切力值更低、感官嫩度评分更高、L值更高且a*值更低（P <.05）。
