55-6 |
Water mobility and distribution in porcine muscle post mortem |
H. C. BERTRAM, H. J. Andersen, and A. H. Karlsson. Dept. of Animal Product Quality, Danish Institute of Agricultural Sciences, PO Box 50, Tjele, DK-8830, Denmark Water-holding capacity (WHC) is a major quality attribute of fresh meat. However, the exact mechanisms determining the WHC of meat are far from understood. Especially, characteristics about proposed water populations in the meat and how they are interrelated with drip loss need to be studied further. Moreover, the distribution and mobility of water in muscle during its conversion to meat and how they are affected by intrinsic and extrinsic factors are poorly elucidated. The objective of the present study was to use Low-Field (LF) NMR relaxation measurements to characterize the proposed water populations in meat and investigate how the distribution and mobility of the water changes post mortem. The macro- and microstructures of porcine meat of different technological quality (high to low WHC) were controlled using either chemical modulators (DMSO, Urea, NaCl) or physical treatments (mincing, homogenization, centrifugation). Subsequently, LF-NMR relaxation measurements were carried out on the different meat samples, and compared with microscopic investigations to further reveal the results in relation to physical features of the pork. Moreover, LF-NMR relaxation was continuously measured during the post mortem period of porcine muscle samples from carriers and non-carriers of the halothane gene using two different cooling profiles. LF-NMR relaxation revealed the presence of three distinct water populations in meat, which could be described due to the physical structure of the meat. Moreover, continuous LF-NMR measurements post mortem showed that two out of three water populations changed characteristics during the first 4 hours. Both chilling regime and genotype affected these changes significantly. The present study reveals that drip loss originates mainly from the extra-myofibrillar water population containing the sarcoplasmatic protein fraction. Moreover during the conversion of muscle to meat, the intrinsic water distribution is heavily affected by genotype and chilling regime through their effect on membrane stability.
Session 55, Muscle Foods: Fresh Meat Quality
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