Park B, Chen Y R, Hruschka W R, Shackelford S D, Koohmaraie M
Beltsville Area Research Center, ARS, USDA, MD 20705-2350, USA.
J Anim Sci. 1998 Aug;76(8):2115-20. doi: 10.2527/1998.7682115x.
Near-infrared reflectance spectra (1,100 to 2,498 nm) were collected on beef longissimus thoracis steaks for the purpose of establishing the feasibility of predicting meat tenderness by spectroscopy. Partial least squares (PLS) analysis (up to 20 factors) and multiple linear regression (MLR) were used to predict cooked longissimus Warner-Bratzler shear (WBS) force values from spectra of steaks from 119 beef carcasses. Modeling used the combination of log(1/R) and its second derivative. Overall, absorption was higher for extremely tough steaks than for tender steaks. This was particularly true at wavelengths between 1,100 and 1,350 nm. For PLS regression, optimal model conditions (R2 = .67; SEC = 1.2 kg) occurred with six PLS factors. When the PLS model was tested against the validation subset, similar performance was obtained (R2 = .63; SEP = 1.3 kg) and bias was small (<.3 kg). Among the 39 samples in the validation data set, 48.7, 87.7, and 97.4% of the samples were predicted within 1.0, 2.0, and 3.0 kg, respectively, of the observed Warner-Bratzler shear force value. The optimal PLS model was able to predict whether a steak would have a Warner-Bratzler shear force value < 6 kg with 75% accuracy. The R2 of MLR model was .67, and 89% of samples were correctly classified (< 6 vs > 6 kg) for Warner-Bratzler shear force. These data indicate that NIR is capable of predicting Warner-Bratzler shear force values of longissimus steaks. Refinement of this technique may allow nondestructive measurement of beef longissimus at the processing plant level.
采集了牛肉胸最长肌牛排的近红外反射光谱（1100至2498纳米），目的是确定通过光谱法预测肉嫩度的可行性。使用偏最小二乘法（PLS）分析（最多20个因子）和多元线性回归（MLR），根据119头牛胴体牛排的光谱预测熟制胸最长肌的Warner-Bratzler剪切（WBS）力值。建模使用log(1/R)及其二阶导数的组合。总体而言，极硬牛排的吸收率高于嫩牛排。在1100至1350纳米波长之间尤其如此。对于PLS回归，六个PLS因子时出现最佳模型条件（R2 = 0.67；SEC = 1.2千克）。当PLS模型针对验证子集进行测试时，获得了相似的性能（R2 = 0.63；SEP = 1.3千克），偏差较小（<0.3千克）。在验证数据集中的39个样本中，分别有48.7%、87.7%和97.4%的样本预测值在观察到的Warner-Bratzler剪切力值的1.0、2.0和3.0千克范围内。最佳PLS模型能够以75%的准确率预测牛排的Warner-Bratzler剪切力值是否<6千克。MLR模型的R2为0.67，89%的样本在Warner-Bratzler剪切力方面被正确分类（<6千克与>6千克）。这些数据表明近红外能够预测胸最长肌牛排的Warner-Bratzler剪切力值。该技术的改进可能允许在加工厂层面无损测量牛肉胸最长肌。
