Near infrared spectroscopy as an on-line method to quantitatively determine glycogen and predict ultimate pH in pre rigor bovine M. longissimus dorsi

The potential of near infrared (NIR) spectroscopy as an on-line method to quantify glycogen and predict ultimate pH (pHu) of pre rigor beef M. longissimus dorsi (LD) was assessed. NIR spectra (538 to 1677 nm) of pre rigor LD from steers, cows and bulls were collected early post mortem and measurements were made for pre rigor glycogen concentration and pHu. Spectral and measured data were combined to develop models to quantify glycogen and predict the pHu of pre rigor LD. NIR spectra and pre rigor predicted values obtained from quantitative models were shown to be poorly correlated against glycogen and pHu (r2 = 0.23 and 0.20, respectively). Qualitative models developed to categorise each muscle according to their pHu were able to correctly categorise 42% of high pHu samples. Optimum qualitative and quantitative models derived from NIR spectra found low correlation between predicted values and reference measurements.