Prediction of beef quality attributes from early post mortem near infrared reflectance spectra

The potential of predicting beef quality attributes after ageing from early post mortem near infrared (NIR) reflectance spectroscopy (1100-2500 nm) has been studied. Altogether, 127 hot boned, Longissimus dorsi muscles from both bulls and cows were investigated in two separate studies. 36 of these carcasses were low voltage electrically stimulated. NIR recordings were obtained 2-30 h post mortem on fresh, sliced loin, while the quality assessments were performed after 2 or 7 days ageing at 4 degrees C on frozen/ thawed beef. Spectral changes during rigor mortis were not related to the ageing potential of the individual loin samples. Predicting final tenderness from NIR spectra recorded at different post mortem times yielded predictive models. However, the multivariate correlation coefficients of the models were relatively low, for example, Warner-Bratzler (WB) shear press measurements ranged from 0.47 to 0.55. Making separate prediction models based on genders yielded models for WE shear press with correlation coefficients up to 0.68. Prediction from sensory tenderness gave prediction models with lower correlation coefficients. Intramuscular fat content in intact meat was predicted with correlation coefficients of 0.78-0.85, and prediction errors (RMSEP) of 1.2-1.4%. The results obtained in this study do not support that early post mortem NIR spectroscopy can be used as precise predictor of final tenderness. (C) 2000 Elsevier Science Ltd. All rights reserved.