Impact of chemical inputs on the post-harvest storability of onion bulbs

The objective of this study is to contribute to a better understanding of the effects of organic and conventional cultivation on the content of phenolic compounds and antioxidant activity during storage of onions. Two solvents were used to optimize the extraction of these compounds. The results showed that acetone is the best solvent for phenolic compounds, whereas methanol is the best solvent for evaluating antioxidant activity. Organic onions also have the highest content of polyphenols (0.35 ± 0.001 mg GAE/g fresh matter (FM)), total flavonoids (0.63 ± 0.001 mg EQ/g FM), and the highest antioxidant activity (0.1077 mg EAA/g FM). In terms of flavonoid and polyphenol content and antioxidant activity, the organic bulbs were better preserved during storage compared to the conventionally grown bulbs and should be preferred for consumption. The best time to consume the organic onions is five or six months after they have been harvested, in order to obtain the highest levels of antioxidants.