Influence of temperature, voltage gradient and electrode on ascorbic acid degradation kinetics during ohmic heating of tropical fruit pulp

Abstract

Vitamin C also known as ascorbic acid is one of the most heat sensitive vitamins. Tropical fruits are a good source of vitamin C, but this vitamin is lost during processing due to high temperature. Ohmic heating is attempted as an alternative technique for the preservation of tropical fruit pulp. The objective of this study was to evaluate the influence of change in temperature, voltage gradient and electrode on vitamin C degradation in the tropical fruit pulps including papaya, sapota and guava, when it is ohmically heated. It was observed that with increase in temperature and voltage gradient, the ascorbic acid content decreased of all the fruit pulp test. Ohmic heating experiment was conducted with two different electrode viz stainless steel and titanium electrode. Ohmic heating experiment when performed with titanium electrode showed better retention of ascorbic acid. A separate experiment was conducted to study the effect of ohmic time on ascorbic acid degradation. Ascorbic acid degradation is also studied during the storage of the ohmic heated pulp. Ascorbic acid content decreased with increase in ohmic heating time and also with increase in storage days.