Ascorbic acid degradation kinetics during conventional and ohmic heating

Ascorbic acid (vitamin C) degradation during electrical and conventional he ating was studied to determine if the presence of an electric field altered the rate of degradation. Experiments were performed using a static ohmic h eating 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 a cid degradation. Pseudo first order degradation kinetics were observed for both conventional and ohmic cases. The activation energy and frequency fact or for the conventional case was 12.6 kcal/mol and 19.95 x 10(5) min(-1), r espectively; for the ohmic case, values were 12.5 kcal/mol and 19.59 x 10(5 ) min(-1). The effect of electrolysis on ascorbic acid degradation was also examined. Gas production and dissolution appeared dto occur with stainless steel electrodes, and was not evident with specially coated titanium elect rodes. These phenomena did not affect ascorbic acid concentration.