Among the techniques based on light interactions with biological tissues, fluorescence polarization offers a selective means of characterizing the organization of biological tissues. This paper presents a methodology for investigating the fluorescence polarization of muscle tissues in to obtain structural information, and specifically the structural modifications caused by meat ageing. A theoretical model of fluorescence anisotropy based on geometrical distribution and properties of tryptophan, the major fluorophore in muscle tissues, is proposed. Experimental data are fitted with the model and fitting parameters (C1, C2 and τ) are tracked during meat ageing. Results presented demonstrate how the method is able to show muscle structure modification during ageing. They highlight changes in structural proteins along the main axis of myofibrils and changes in the tryptophan environment resulting from the physicochemical and enzymatic processes at work during ageing.