SIMULATION OF ASCORBIC ACID STABILITY DURING HEAT PROCESSING AND CONCENTRATION OF GRAPEFRUIT JUICE

The kinetics of ascorbic acid loss in grapefruit juice was determined for thermal and concentration processes. The results indicate an apparent first order anaerobic reaction which is dependent on temperature and degree of product concentration but not on initial ascorbic acid content. The effect of temperature on rate of reaction follows the Arrhenius equation with energy of activation ranging from 5 to 11.3 Kcal/mole for solids content of 11 to 62†Bx, respectively. Using a polynomial curve fitting technique, an empirical kinetic equation correlating rate of reaction with temperature and degree of concentration was established. Based on this empirical equation, a prediction mathematical model was formulated and proved useful in analyzing the extent of ascorbic acid retention in grapefruit juice during commercial thermal and concentration processes.