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The ability of NMR to predict purge from vacuum-packed pork that was stored for 9 days was investigated. T 2 relaxation was measured at 24 h post mortem ( p.m. ) and again after 9 days of chilled storage. NMR measurements from day 1 p.m. were limited in predicting day-9 purge (|r| = 0.37–0.52). The root mean square error of linear regression (RMSD) for measuring day-9 purge using the relaxation time of intra-myofibrillar water (T 21 ) measured on day 1 p.m. (r = −0.46) was 1.31% (range: 1.15–7.69% purge), corresponding to ±2.62% (2 × RMSD) prediction error of purge with 95% probability. This indicated that for purge production rate, the distribution and mobility of water in meat on day 1 p.m. may be of little relevance. Further tests were conducted to explain this poor predictability, by taking NMR measurements of water mobility and distribution made on the same meat sample (taken at 96 h p.m. ) every day, during a 9-day storage period. By analyzing the T 21 and T 22 domains every day, it was revealed that during the first 5-day of storage, water (86%) moved from intra-myofibrillar space to extra-myofibrillar space. However, this movement did not result in detectable drip. A major liquid loss followed between days 6 and 7 and ceased day 8. This complexity of the water movement between domains during storage may explain the poor predictability of day-9 purge using NMR measurements from day 1. [ABSTRACT FROM AUTHOR]

The potential of using NMR as a reference method for WHC measurement in porcine longissimus dorsi was investigated. The accuracy of NMR when measuring small water changes was assessed in a model system and in muscles. Visible/near infrared (Vis/NIR) and X-ray were used as potential online spectroscopic methods to assess WHC on 40 muscles. Drip loss and spin–spin relaxation were also measured. Calibration models were built using partial least squares regression (PLSR) with Vis/NIR or X-ray spectra as input and NMR or drip loss values as output. The slowest spin–spin relaxation time (T 22 ) showed higher correlation with both Vis/NIR ( R CV 2 = 0.66) and X-ray spectra ( R CV 2 = 0.76) than EZ-DripLoss values, demonstrating NMR has potential as a reference method for WHC measurement. NMR was more robust against variation along the length of the muscle when compared to the EZ-DripLoss method. [ABSTRACT FROM AUTHOR]