Chemical marker M-2 (4-hydroxy-5-methyl-3(2H)-furanone) can be used as a tool to evaluate heating patterns of foods in microwave sterilization. This research studied the kinetics of the M-2 formation in mashed potato as influenced by temperature and salt content. Mashed potato (83.12% moisture content) with 1.5% D-ribose was heated in the capillary tubes at four temperature levels. Chemical marker M-2 yield was obtained using high performance liquid chromatography. Formation of M-2 in plain mashed potato was a first-order reaction. The rate constant changed with temperature following an Arrhenius relationship. For kinetic parameters estimation, one-step non-linear regression was the best followed by modified two-step regression. Amino acid was the limiting element in the formation M-2 in mashed potato. The salt content of 0-1% had no influence on the chemical marker yield. Addition Of L-lysine more than 1% resulted in too dark color after sterilization treatments. (c) 2005 Elsevier Ltd. All rights reserved.