Effects of phenolic enrichment on vitamin C and antioxidant activity of commercial orange juice

The autoxidation process of vitamin C in orange juice is the most important cause of quality loss during its storage. We evaluated the enrichment with different concentrations of a phenolic extract in a commercial orange juice for some qualitative parameters such as the content of vitamin C, phenolic compounds, and antioxidant activity. The lowest concentration of phenols produced the most stable enriched juice. In particular, we observed an inverse correlation between phenolic concentration and vitamin C retention in enriched juices. DPPH assay results confirmed this trend, correlated more to the vitamin antioxidant effect. TEAC results instead, were similar for the different juice samples, probably influenced by the phenolic content. The application of this study is the production for the industry of new functional drinks such as juices enriched with phenolic ingredients that show increased stability concerning those without addiction.