Influence of the spatial organization of the perimysium on beef tenderness.

The spatial distribution of the intramuscular connective tissue (IMCT) in four types of beef muscle (Biceps femoris, Infraspinatus, Longissimus thoracis, and Pectoralis profundus) was examined using histology and magnetic resonance imaging (MRI). The surface and the length of the IMCT and the surface of the myofiber bundles were evaluated by image analysis. The texture of the cooked meat from these muscles was measured both instrumentally by a compression test and by sensory analysis. The relationship between muscle structure and meat texture was studied by general discriminant analysis. The models obtained could assign correctly up to 87% of the samples to two tenderness classes. Histology and MRI provided complementary information about the microscopic and macroscopic IMCT structures, respectively. Both were necessary to predict sensory tenderness whereas only the MRI measurements were necessary to predict instrumental toughness. Tough muscles had smaller MRI myofiber bundles (0.7-1 mm radius) than tender muscles.

Meat bolus properties in relation with meat texture and chewing context.

During chewing the meat sample is fragmented by compressive and shear bite forces while saliva is incorporated. At the end of this process meat is transformed into a bolus with specific properties, which elicit deglutition. This study aims to analyze the mechanical properties of the boli and juice-saliva interactions in different chewing contexts. Two groups of subjects with different chewing efficiencies participated in the study: healthy dentate (n=9) and denture wearers (n=7). Meat boli were obtained from two beef samples exhibiting different textures obtained by varying aging time and cooking temperature. Variables linked to saliva-food matrix interactions (boli volume and weight, dry matter content) were not dependent on muscle fiber disorganization evaluated using shear tests. No texture effect was observed from the mechanical properties of the boli, whatever the chewing context. Denture wearers swallowed less disorganized boli but with a similar water content as dentate. Between subjects variability was the highest for saliva-food interactions and the lowest for mechanical properties. The variations obtained in meat boli characteristics could have consequences on sensory properties perception and on the digestion process.