Kinetics of chemical marker formation in whey protein gels for studying microwave sterilization

The kinetics of 4-hydroxy-5-methy-3(2H)-furanone (M-2) formation in a model food system (20% whey protein gel) was determined for studying cumulative time-temperature effects in high-temperature-short-time processes. M-2 was formed from D-ribose and amines through non-enzymatic browning reactions and enolization under low acid conditions (pH > 5). The order of the reaction for M-2 formation was determined by non-linear regression analysis and further confirmed by graphical method. M-2 formation followed a first-order kinetics and the rate constant temperature dependence was described using an Arrhenius relationship. The reaction rates and activation energy were determined using two-step, multi-linear and non-linear regression analyses. This study also demonstrated the use of M-2 formation in determining the cumulative heating effect in a model food system subjected to 915 MHz microwave heating. (C) 2003 Elsevier Ltd. All rights reserved.