Predicting intramuscular fat, moisture and Warner-Bratzler shear force in pork muscle using near infrared reflectance spectroscopy

Partial least-squares (PLS) models based on visible (Vis) and near infrared reflectance (NIR) spectroscopy data were explored to predict intramuscular fat (IMF), moisture and Warner Bratzler shear force (WBSF) in pork muscles (m. longissimus thoracis) using two sample presentations, namely intact and homogenized. Samples were scanned using a NIR monochromator instrument (NIRSystems 6500, 400 to 2500 nm). Due to the limited number of samples available, calibration models were developed and evaluated using full cross validation. The PLS calibration models developed using homogenized samples and raw spectra yielded a coefficient of determination in calibration (R-2) and standard error of cross validation (SECV) for IMF (R-2=0(.)87; SECV=1(.)8 g/kg), for moisture (R-2=0(.)90; SECV=1(.)1 g/kg) and for WBSF (R-2=0(.)38; SECV=9(.)0 N/cm). Intact muscle presentation gave poorer PLS calibration models for IMF and moisture (R-2 < 0(.)70), however moderate good correlation was found for WBSF (R-2=0(.)64; SECV=8(.)5 N/cm). Although few samples were used, the results showed the potential of Vis-NIR to predict moisture and IMF using homogenized pork muscles and WBSF in intact samples.