The dynamics of bioactive compounds and their contributions to the antioxidant activity of postharvest chive (Allium schoenoprasum L.)

Organosulfur compounds, phenolic compounds, and ascorbic acids (AsA) are known to account for the bulk of chive's (Allium schoenoprasum L.) antioxidant properties. This study uncovered the contribution of each of these compounds to the chive's antioxidant activity under different storage conditions. The results showed that room temperature (RT) accelerated the accumulation of reactive oxygen species, though phenolics, organosulfur compounds, activities of antioxidant enzymes, and scavenging activity toward hydroxyl radical ((OH)-O-center dot) and superoxide anion (O-2(center dot-)) were observed to be enhanced in chives stored at RT. In contrast, AsA content, DPPH (1,1-diphenyl-1-picrylhydrazyl) scavenging and FRAP (ferric reducing antioxidant power) activity of the chive were increased by LT on day 5. Furthermore, S-alk(en)ylcysteine sulfoxides (CSOs) showed (OH)-O-center dot scavenging and weak DPPH scavenging but had no O-2(center dot-) scavenging and FRAP capacity. Volatile organosulfur compounds showed no antioxidant activities. Conclusively, the data demonstrated that AsA was largely responsible for DPPH scavenging and FRAP activity of the chive, while phenolic compounds, especially vanillic acid and p-hydroxybenzoic acid, were primarily responsible for (OH)-O-center dot and O-2(center dot-) scavenging activity.