Reaction at Limited Water Concentration 1. Sucrose Hydrolysis

Abstract

SUMMARY—To enable development of a model describing reaction kinetics in dehydrated foods, we studied sucrose hydrolysis at limited water concentration. Saturated sucrose solutions containing various acids and inert solid materials gave identical rate constants and energy of activation as predicted from dilute solutions. Reaction rates in freeze‐dried systems humidified to low moisture contents indicated that any equation describing the rate of hydrolysis must include a term for the velocity of dissolution of solid sucrose into the surface water. The rate of hydrolysis was a pseudo first‐order reaction obeying the same kinetics as in dilute solution; the rate of dissolution became rate‐limiting when the initial supply of dissolved sucrose was exhausted.