Effects and thermodynamics of copigments on anthocyanins in strawberry juice under different thermal sterilization conditions

As a product with high economic value and commodity value, strawberry juice is easy to fade during processing and storage. To mitigate color degradation in strawberry juice, citric acid, and tannic acid were evaluated as copigments during thermal processing. Both compounds demonstrated significant color stabilization, with optimal effects at 4 mg/mL concentration. Thermal treatment (60–80°C) revealed enhanced anthocyanin stability through reduced degradation rates (e.g. tannic acid reduced degradation by 42% at 60°C) and extended half-life (up to 14.65 hours with tannic acid), with tannic acid exhibiting superior copigmentation efficacy compared to citric acid (p < .05). At the same time, the effect of the tannic acid group is better than that of citric acid, indicating that tannic acid has a stronger stabilizing effect on anthocyanins, which is more suitable to be combined with thermal sterilization to reduce the color decay of strawberry juice in the actual production process.