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

Abstract 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.

摘要：橙汁中维生素C的自氧化过程是其储存期间品质损失的最主要诱因。本研究以市售橙汁为基质，采用不同浓度的酚类提取物（phenolic extract）进行强化处理，并针对维生素C含量、酚类化合物含量及抗氧化活性等多项品质参数开展评估。结果显示，酚类物质浓度最低的实验组所制备的强化橙汁稳定性最优。尤为关键的是，本研究观察到强化橙汁中的酚类浓度与维生素C保留率呈负相关关系。DPPH自由基清除试验（DPPH assay）的结果验证了这一趋势，且该趋势与维生素的抗氧化效应关联更为紧密。而TEAC抗氧化试验（TEAC）的结果在不同橙汁样品间表现相近，这一现象可能受酚类物质含量的影响。本研究的应用场景为工业生产新型功能饮品，例如添加酚类成分的强化果汁，相较于未添加酚类成分的普通果汁，此类强化果汁的稳定性显著提升。