| Abstract: | The back-scatter of light (400–800 nm) from bovine m longissimus lumborum (n=47) was measured with a fibre-optic probe fitted with crossed polarisers to exclude Fresnel reflectance. Unlike normal fibre-optic spectra (which may be relatively flat), back-scatter was approximately proportional to wavelength, being low at 400 nm and high at 800 nm. The shape of the spectrum was modified by myoglobin absorbance, with a Soret minimum at 430 nm. Connective tissue fluorescence (365 nm excitation, 400–550 nm emission) was measured through a single optical fibre moving down the longitudinal axis of the muscle. Back-scatter at 430 nm was correlated positively with minimum fluorescence (r=0·73, P<0·001), the area under the fluorescence signal cm−1 (r=0·81, P<0·001) and fluorescence peaks cm−1 (r=0·46, P<0·005). Back-scatter at 800 nm was correlated weakly and negatively with minimum fluorescence (r=-0·28, P<0·05) and peaks cm−1 (r=-0·26, P<0·05). Thus, in the probe detection of connective tissue fluorescence in meat, errors caused by differences in myoglobin concentration may exceed those caused by differences in pH-related light scattering. © 1997 SCI. |
