Objectivation of the ``grain of meat'' notion and prospect of utilisation to evaluate the tenderness of Charolais beef meat

The assessment of the meat ``grain'' size is an empirical method used by some butchers in France to predict the tenderness of meat: the finer the grain the higher the quality. Four studies are presented here. After a characterization of this notion using an ethnological approach, two grids were built to objectivate the way of evaluating grain of meat on live animals and carcasses. The second aim was to characterize the main muscles used by the experts to rate the grain of meat. The last aim was to establish the relation between the score of meat grain estimated on the carcass and the tenderness of the longissimus thoracis muscles estimated by sensory evaluations. A group of 16 criteria were identified on the carcass as effective to anticipate overall ``grain of meat'' score. ``Fine grain'' carcasses were associated with lower lipid content than ``coarse grain'' in longissimus thoracis muscles, leading to significantly lower scores of flavor intensity without any impact on juiciness scores. No significant relation appeared between grain of meat and tenderness. The shear force needed to cut a broiled sample was found significantly higher for ``coarse grain'' carcasses than for ``fine grain'' ones. The total collagen in the ``coarse grain'' group was significantly higher than those from the ``fine grain'' group without any impact on collagen solubility. Taken together, these results allow hypothesizing that ``fine grain'' could have a positive impact on meat quality traits. The differences underlined are nevertheless very muscle-dependant and remain to be confirmed in larger trials.