Monitoring of denaturation processes in aged beef loin by Fourier transform infrared microspectroscopy

We present the results of a Fourier transform infrared (FT-IR) microspectroscopic study using conventional FT-IR microscopy and FT-IR imaging to detect the denaturation process during four different heating temperatures (raw, 45, 60, and 70 degrees C) spatially resolved in bovine cryosections from longissimus dorsi muscle. FT-IR imaging, employing a focal plane array detector, which allowed the simultaneous collection of spectra at 4096 pixels, enabled the investigation of the heat-induced changes in the two major meat constituents, i.e., myofibrillar and connective tissue proteins, spatially resolved. The infrared spectra of both compounds revealed that the major spectral changes involved an increase in beta-sheet and a decrease in alpha-helical structures, which appeared to be much more pronounced for the myofibers than for the connective tissue. These conformational changes could be correlated to the denaturation of the major meat proteins, such as myosin, actin, and collagen.