A method for simultaneous fluorometry and rheology of connective tissue in bulk meat

A probe tipped with optical fibres was mounted on the load cell of a compression tester and pushed into well-aged beef rib roasts (Canada Grade AAA, n = 6, 33 ± 3.6 days post-mortem). Fluorescence (F; excitation 365 nm, emission >420 nm) and reflectance (R; 365 nm) were measured through single optical fibres. Diffuse R was measured using different fibres for illumination and detection, thus responding to tissue between the two fibres. Replication was by a matrix pattern of penetrations on single roasts. For example, in a typical roast, F was correlated with the force of penetration (mean r = 0.86 ± 0.06, n = 20, all P < 0.001). R was less (P < 0.001) strongly correlated with penetration force (mean r = 0.46 ± 0.10, n = 20, all P < 0.001). F signals from connective tissue contained less peaks than R signals from both connective and adipose tissue (respectively, 2.75 ± 0.43 versus 5.57 ± 0.67 peaks cm−1, P < 0.001, n = 20 pairs) and F peaks were wider than R peaks (respectively, 3.54 ± 0.88 versus 1.38 ± 0.19 mm, P < 0.001, n = 20 pairs). For the spinales dorsi aponeurosis, the depth at which peak force was reached was strongly correlated with the depths at which both peak F and peak R were reached (r = 0.98, P < 0.001, n = 20 for both). Diffuse R was only weakly correlated with penetration force (mean r = 0.29 ± 0.12 with only 5/10 correlations significant P < 0.001). This new method showed the primary resistance to dorso-ventral penetrometry of well-aged beef rib roasts originated from connective tissue.