EFFECT OF MOISTURE CONTENT AND TEMPERATURE ON SOME ASPECTS OF NONENZYMATIC BROWNING IN DEHYDRATED APPLE

Abstract
Dehydrated apple was heat‐damaged at various constant moisture contents and constant temperatures and the optical density at 282 nm (OD282) of its methanol‐water extracts subsequently determined. Moisture and temperature ranges studied simulate the conditions that usually would prevail during air dehydration of apple. It was found that the rate of increase of OD282 which is associated with the presence of 5‐hydroxy‐methyl‐furfural—followed a zero order reaction kinetics m the range of variables studied. The rates of OD282 increase were determined and correlated with moisture content and temperature. The effect of temperature on the rates is reported as apparent activation energies. It was found that the apparent energy of activation increased with decreasing moisture content.