Ascorbic acid degradation and color changes in acerola pulp during ohmic heating: Effect of electric field frequency

• Studied effects of electric field frequency on quality parameters during ohmic heating.
• The electric field frequency was evaluated in the range between 10 and 105 Hz.
• Low frequency led to higher ascorbic acid degradation and greater color changes.
• Between 100 and 105 Hz similar ascorbic acid degradation rates were observed.
• High electric field frequency did not affect the degradation of ascorbic acid.

The effect of the electric field frequency on ascorbic acid degradation and color changes in acerola pulp during ohmic heating was evaluated and this technology was compared with the conventional heating process. The electric field frequency was evaluated in the range between 10 and 105 Hz. The use of low electric field frequency (10 Hz) led to greater ascorbic acid degradation and higher color changes probably due to the occurrence of electrochemical reactions. Above 100 Hz these reactions were minimized and, as a result, ohmic and conventional heating processes showed similar degradation rates of ascorbic acid and similar color changes. The use of high electric field frequency did not affect the degradation kinetics of ascorbic acid and pigment compounds. This indicates that the ascorbic acid molecule predisposition for hydrogen donation in redox reactions was not affected by the rapidly varying electric field.