Abstract:

The fruit skins of different five cultivars of eggplants were extracted with hydrochloride acid-acidified ethanol (1:9, V/V) under the assistance of ultrasonic to comparatively determine anthocyanidin contents in them and evaluate the effects of natural light exposure ways, indoor natural light exposure in combination with heating at different temperatures for 1 h, pH, metal ions in solution, common food additives, oxidizers and reducers on the stability of the extracted anthocyanidins. The skin of Brown eggplant contained the largest amount of anthocyanidins among five cultivars. The content of anthocyanidins in purple eggplant skin was approximately 86.48%－82.74% higher than that in green eggplant skin. The anthocyanidins extracted from the fruit skins of five cultivars of eggplants were all kept stable under light avoiding, low-temperature, weakly acidic and weakly alkaline conditions. Mg2+ had color-enhancing effect on them, while the presence of Mn2+, Zn2+ or Cu2+ made the color lighter. VC also did so. All sucrose, citric acid and sodium benzoate could protect the color to some extent. However, no resistance to oxidizers or reducers was observed. These data suggest that anthocyanidins derived from eggplant skin have extensive application prospects.

Key words: eggplant, anthocyanidin, content, stability