Assessment of tenderness of aged bovine gluteus medius muscles using Raman spectroscopy.

A portable 671 nm Raman system was evaluated as a rapid and non-destructive device for the assessment of beef tenderness using 175 gluteus medius muscles (99 for calibration, 76 for validation) aged at -1 °C and 7 °C for fourteen days. Raman and shear force (SF) measurements were performed with the aged beef. The samples stored at -1 °C showed on average only slightly increased SF values. The correlation of Raman spectra with SF using partial least squares regression yielded cross-validated predictions of SF for both storage temperatures with coefficients of determination R(2)cv=0.33-0.79. Validation with independent samples resulted in predictions with R(2)val=0.33. Using thresholds between 30 and 49N, tough and tender samples could be discriminated with partial least squares discriminant analysis with 70-88% and 59-80% accuracy during cross-validation and validation, respectively. These results demonstrate the principle feasibility to predict the SF and thus toughness of raw, aged gluteus beef cuts with a portable Raman device showing potential for grading beef cuts.

Prediction of pork quality at the slaughter line using a portable Raman device.

Raman spectroscopy is providing a fingerprint of the early postmortem metabolism in meat. In this study, for the first time, Raman spectroscopy is shown to measure and predict quality traits of intact muscles at the slaughtering process. Porcine semimembranosus muscles (N=151) were measured 30-60 min post mortem at the veterinarian line of a commercial abattoir using a prototype handheld Raman device. The Raman spectra were regressed against technologically important quality traits as measured with classic reference methods. Predicting pH35, pH24 and drip loss with PLSR yielded coefficients of determination of 0.75, 0.58 and 0.83 and root mean square errors of cross validation of 0.09, 0.05 and 0.6%, respectively. This is demonstrating the on-line potential of early postmortem Raman spectra to measure pH35 and to predict pH24 and drip loss.

Preliminary investigation on the relationship of Raman spectra of sheep meat with shear force and cooking loss.

A prototype handheld Raman system was used as a rapid non-invasive optical device to measure raw sheep meat to estimate cooked meat tenderness and cooking loss. Raman measurements were conducted on m. longissimus thoracis et lumborum samples from two sheep flocks from two different origins which had been aged for five days at 3-4°C before deep freezing and further analysis. The Raman data of 140 samples were correlated with shear force and cooking loss data using PLS regression. Both sample origins could be discriminated and separate correlation models yielded better correlations than the joint correlation model. For shear force, R(2)=0.79 and R(2)=0.86 were obtained for the two sites. Results for cooking loss were comparable: separate models yielded R(2)=0.79 and R(2)=0.83 for the two sites. The results show the potential usefulness of Raman spectra which can be recorded during meat processing for the prediction of quality traits such as tenderness and cooking loss.