Prediction of beef quality attributes from early post mortem near infraredreflectance spectra

The potential of predicting beef quality attributes after ageing from early post mortem near infrared (NIR) reflectance spectroscopy (1100-2500 nm) ha s been studied. Altogether, 127 hot boned, Longissimus dorsi muscles from b oth bulls and cows were investigated in two separate studies. 36 of these c arcasses were low voltage electrically stimulated. NIR recordings were obta ined 2-30 h post mortem on fresh, sliced loin, while the quality assessment s 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 p otential of the individual loin samples. Predicting final tenderness from N IR spectra recorded at different post mortem times yielded predictive model s. However, the multivariate correlation coefficients of the models were re latively low, for example, Warner-Bratzler (WB) shear press measurements ra nged 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 corre lation 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 p ost mortem NIR spectroscopy can be used as precise predictor of final tende rness. (C) 2000 Elsevier Science Ltd. All rights reserved.