Abstract: In this study, the optimal extraction process for flavonoids from eggplants was explored and the contents of flavonoids in eggplants from different cultivars were compared. Single-factor tests were adopted to investigate the effects of ethanol concentration, extraction temperature, extraction time and material-liquid ratio on the extraction rate of flavonoids. Based on the single-factor tests, orthogonal tests were used to explore the optimal extraction process. The results showed that the best extraction conditions for flavonoids from eggplants were ethanol concentration of 80%, extraction temperature of 40 ℃, extraction time of 80 min and material-liquid ratio of 1:20. Under the optimal extraction conditions, the extraction rate of flavonoids was up to 2.2%. The contents of flavonoids in 8 eggplant cultivars cultivated in Liaoning province were determined. Flavonoids revealed the highest content after fruit setting for 14 days. As for green eggplant cultivars, the highest flavonoid content was determined in LiaoQie 5 with the content of 56.3 mg/g. Similarly, as for purple eggplant cultivars, the highest flavonoid content was determined in LiYuan purple eggplants with the content of 25.7 mg/g. Therefore, the development and utilization of flavonoids in eggplants were feasible.

Key words: eggplant, flavonoids, extraction technology, cultivars, content