Assessment of Antioxidant Activity of Food Products by Iodometric Determination of Ascorbic Acid and Its Significance in The Prevention of Oxidative Stress
Abstract
Oxidative stress is recognized as a key pathogenetic factor in chronic non-communicable diseases, which makes the assessment of dietary antioxidant intake particularly relevant clinically. The aim of this study was to evaluate the antioxidant activity (AOA) of freshly squeezed lemon, orange, and apple juices using iodometric titration, as well as to examine the effect of heat treatment on the stability of ascorbic acid. A 1% starch solution was used as the indicator, and titration was performed with Lugol’s solution. The results showed that lemon juice had the highest AOA (28 drops to achieve a stable coloration), while apple juice showed the lowest activity (6 drops). Heating samples to 80°C for 10 minutes reduced AOA by 60–67%, confirming the thermal lability of ascorbic acid. The findings support the use of iodometry as an accessible screening method in food biochemistry and justify the recommendation to consume thermally unprocessed fruits and vegetables for the prevention of oxidative stress.