extraction and characterization of quercetin-3-o-rhamnoside from eggplant peel: antioxidant assessment in 3.5% full-fat yogurt

Recent research has increasingly focused on foods that provide energy and medicinal properties to enhance human health. eggplant has gained recognition as a nutritious option, ranking among the top ten vegetables due to its high antioxidant content, which is attributed to its diverse array of phenolic compounds. the peel of purple eggplants is particularly rich in flavonoids and anthocyanins—compounds that play a crucial role in promoting human health through their potent antioxidant effects. this study aimed to extract and identify a flavonoid from eggplant peel using various spectroscopic techniques, including thin-layer chromatography (tlc), infrared spectroscopy (ir), and nuclear magnetic resonance (nmr). furthermore, the antioxidant properties of quercetin-3-o-rhamnoside were evaluated in combination with 3.5% full-fat yogurt over 28 days. specifically, quercetin-3-o-rhamnoside was added to the yogurt at concentrations of 0.01% and 0.02%, and these were compared to the synthetic antioxidant bht. the results demonstrated that increasing the concentration of quercetin-3-o-rhamnoside led to a higher percentage of free radical inhibition. however, antioxidant activity was highest on day 1 and declined by day 28. these findings suggest that consuming eggplant peel (solanum melongena l.) may provide health benefits, highlighting its potential as a valuable addition to functional foods and a natural source of antioxidants.