Maillard reaction product (MRP) are indicators for heat treatment of food. They are used as marker of the nutritional quality of food. Pyrraline is an advanced Maillard reaction product, derived from reaction of glucose with lysine residues. References: Nakayama, T. et al. Agric. Biol. Chem. 1980; 44: 1201. Miller, R. et al. Acta Chem. Scand. 1984; B38: 689. Öste, R.E. et al. J. Agric. Food. Chem. 1987; 35: 938. Chiang, G.H. J. Agric. Food. Chem. 1988; 36: 506. Sengl, M. et al. J. Chromatogr. 1989; 463: 119. Schuessler, U. and Ledl, F. Z. Lebensm Unters Forsch 1989; 189: 32. Schuessler, U. and Ledl, F. Z. Lebensm Unters Forsch 1989; 189: 138. Hayase, F. et al. J. Biol. Chem. 1989; 263: 3758. Henle, T. and Klostermeyer, H. Z. Lebensm Unters Forsch 1993; 196: 1. Portero-Otin, M. et al. Biochem. Biophys. Acta. 1995; 1247: 74. Henle, T. and Bachmann, A. Z. Lebensm Unters Forsch 1996; 202: 72. Nagaraj, R.H. et al. Arch. Biochem. Biophys. 1996; 325: 152.