Water Diffusion to Probe Meat Microstructure

The ability of meat microstructures to retain water plays a crucial role, both for eating quality of fresh meat and for functional properties of raw meat for further processing. In the quest for setting up rapid methods to study this fundamental quality trait, time domain nuclear magnetic resonance (TD-NMR) has gained a primary role, due to the possibility to observe, by T2 weighted signals of protons, water located outside the myofibrils, thus easily lost upon storage or cooking. Diffusion weighted signals could in principle be used to monitor the shape and dimension of the pores water is confined into, thus boosting the information offered by TD-NMR. Unfortunately such possibility has been barely explored, probably due to the difficulty of robustly consider the overwhelming meat matrix characteristics involved. The present work describes a parsimonious model devoted to give information about ratio and exchange rate between intra and extra myofibrillar water populations, diffusion coefficient of the intra and extra myofibrillar water, and diameter of the myofibrillar cells. In order to test the potentialities of our model, we registered diffusion and T2 weighted signals at 20 MHz on fresh meat from pectoralis major muscle from commercial female turkeys (slaughter weight of 8 kg, reached at 12 weeks of age). This kind of meat was selected because it eased the observation of the signals along and across meat fibers. We then purposely modified water populations ratio and myofibrillar spaces shape, by taking advantage of freezing at domestic conditions. The described model managed to nicely predict the consequences of the imposed modifications