Quantification of Connective Tissue (Hydroxyproline) in Ground Beef by Autofluorescence Spectroscopy

Autofluorescence spectra (excitation wavelengths 300, 332, 365, 380 and 400 nm) were obtained by an optical system to determine collagenous connective tissue (hydroxyproline) and fat content in ground beef. Chemically determined contents ranged from 0.72–7.12% connective tissue and 1.5–17.7% fat. Partial least squares regression (66 samples) resulted in the lowest root mean square error of 0.37% connective tissue (R=0.97) and 1.89% fat (R=0.84) for excitation wavelengths 380 and 332 nm, respectively. The wavelength 332 nm may be feasible for simultaneous determination of fat and connective tissue. Autofluorescence spectroscopy might be well suited for rapid on-line determination of collagen in ground beef.