ASCORBIC ACID DEGRADATION KINETICS DURING CONVENTIONAL and OHMIC HIEATING

Abstract

Ascorbic acid (vitamin C) degradation during electrical and conventional heating was studied to determine if the presence of an electric field altered the rate of degradation. Experiments were peiformed using a static ohmic heating apparatus, and heating histories were matched using applied voltage in the electrical case and hot oil in the conventional case. A statistical analysis showed that electric field has no significant effect on ascorbic acid degradation. Pseudo first order degradation kinetics were observed for both conventional and ohmic cases. the activation energy and frequency factor for the conventional case was 12.6 kcal/mol and 19.95 × 105 min-1, respectively; for the ohmic case, values were 12.5 kcal/mol and 19.59 × 1O5 min-1. the effect of electrolysis on ascorbic acid degradation was also examined. Gas production and dissolution appeared