Changes in antioxidant compounds during the shelf life of commercial tomato juices in different packaging materials.

Tomatoes provide an optimal mix of dietary antioxidants that may be responsible for the reported health benefits of tomato consumption. However, technological processing, packaging materials, and storage conditions have an impact on the nutritional quality of tomato products by affecting the stability of antioxidant nutrients to different extents. In this study, we evaluated the stability of the antioxidant compounds (lycopene, ascorbic acid, total phenols, and total flavonoids) present in commercially available tomato juices during storage extended for 12 months at three different temperatures (8, 22, and 37 degrees C). To further characterize the impact of storage conditions, two commonly used packaging materials (Tetra pack and glass bottles) were used to determine whether packaging materials affect antioxidant stability. Overall, the total lycopene, total phenolic compounds, and total flavonoids remained almost stable during storage for 12 months, regardless of the packaging material used, indicating that tomato juices maintain their nutritional value in terms of antioxidant composition during their shelf life. However, ascorbic acid was the most labile antioxidant and was markedly affected by storage conditions. The hydrophilic total antioxidant activity (TAA) paralleled the losses in ascorbic acid content, whereas the lipophilic TAA remained substantially stable throughout the storage trial.