Feasibility of the direct application of near-infrared reflectance spectroscopy on intact chicken breasts to predict meat color and physical traits

Physical and color characteristics of chick- en meat were investigated on 193 animals by directly applying a fiberoptic probe to the breast muscle and us- ing the visible-near-infrared (NIR) spectral range from 350 to 1,800 nm. Data on pH was recorded 48 h post- mortem (pH); lightness (L*), redness (a*), and yellow- ness (b*) 48 h postmortem; thawing and cooking losses and shear force after freezing. Partial least squares regressions were performed using untreated data, raw absorbance data (log(1/R)), and multiplicative scat- ter correction plus first or second derivative spectra. Models were validated using full cross-validation, and their predictive ability was determined by root mean square error of cross-validation (RMSECV) and correla- tion coefficient of cross-validation (rcv). Means (±SD) of pH, L*, a*, b*, thawing loss, cooking loss, and shear force were 5.83 ± 0.13, 44.54 ± 2.42, −1.90 ± 0.62, 3.21 ± 3.28, 4.84 ± 2.44%, 19.39 ± 2.95%, and 16.08 ± 3.83 N, respectively. The best prediction models were developed using log(1/R) spectra for b* (rcv = 0.93; RMSECV = 1.16) and a* (rcv = 0.88; RMSECV = 0.29), while a medium predictive ability of NIR was obtained for pH, L*, and thawing and cooking losses (rcv from 0.69 to 0.76; RMSECV from 0.01 to 1.73). Finally, pre- dicted model for shear force (rcv = 0.41; RMSECV = 3.18) was unsatisfactory. Results suggest that NIR is a feasible technique for the assessment of several quality traits of intact breast muscle.