| Abstract
| - Vidalia onion varieties Nirvana, DPS 1032, Yellow 2025, King-Midas, and SBO 133 grown at Vidalia,Georgia, were analyzed for flavonoid content. A high-performance liquid chromatographic (HPLC)method with photodiode array detection was used for quantification. Compounds were analyzed asaglycons after acid hydrolysis with 1.2 M HCl. Identification of each compound was based oncomparison of its retention time and UV spectra with those of pure commercial standards. Threemajor flavonoids, kaempferol, myricetin, and quercetin, were identified and quantified. Quercetin wasthe major flavonoid (7.70−46.32 mg/100 g fresh weight, FW) present in all varieties, followed bymyricetin (2.77−4.13 mg/100 g FW). Minor quantities of kaempferol (1.10−1.98 mg/100 g FW) werealso detected. The total polyphenols and Trolox equivalent antioxidant capacity (TEAC) ranged from73.33 to 180.84 mg/100 g FW and 0.92−1.56 μM TEAC/g FW, respectively. A positive but weakercorrelation was obtained for total polyphenols versus antioxidant capacity. Nevertheless, a strongercorrelation (r2 = 0.34) was obtained between flavonoid content versus antioxidant capacity. The dataindicate that Vidalia onions are a rich source of quercetin, and they also contain myricetin andkaempferol. Keywords: Antioxidant capacity; flavonoids; HPLC diode-array; total polyphenols; Vidalia onion
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