Table 1.
HPLC quantification of flavonols and anthocyanins in two varieties of A. cepa and A. × cornutum extracts.
| A. × cornutum (tR, min) | A. cepa (Yellow Variety) (tR, min) | A. cepa (Red Variety) (tR, min) | |
|---|---|---|---|
| Flavonols a | |||
| Quercetin 3,4′-diglucoside (1) | 618.75 ± 0.36 a (32.52) | 100.40 ± 0.05 c (32.46) | 331.93 ± 0.12 b (32.50) |
| Quercetin 4′-monoglucoside (2) | 617.01 ± 0.40 a (40.47) | 140.43 ± 0.10 c (40.42) | 298.87 ± 0.13 b (40.46) |
| Myricetin (3) | 14.88 ± 0.01 a (42.35) | 8.63 ± 0.01 c (42.31) | 9.31 ± 0.02 b (42.35) |
| Quercetin aglycone (4) | 297.21 ± 0.40 a (47.14) | 60.51 ± 0.06 c (47.09) | 70.10 ± 0.08 b (47.14) |
| Isorhamnetin (5) | 32.07 ± 0.04 a (52.29) | 2.21 ± 0.01 c (52.23) | 13.73 ± 0.01 b (52.28) |
| Anthocyanins a | |||
| Peonidin 3′-glucoside | Nd | 1.11 ± 0.00 (12.38) | Nd |
| Peonidin 3′-glucoside acetate | Nd | Nd | 0.67 ± 0.3 (25.02) |
| Delphinidin 3′-glucoside acetate | 0.23 ± 0.00 (18.71) | Nd | Nd |
| Malvidin 3′-glucoside | 0.05 ± 0.00 b (13.44) | 0.53 ± 0.00 a (12.84) | 0.24 ± 0.00 b (13.28) |
| Cyanidin 3′-glucoside | 0.32 ± 0.01 b (8.47) | 7.85 ± 0.11 a (8.56) | 0.11 ± 0.00 b (8.06) |
| Cyanidin 3′-glucoside acetate | 1.22 ± 0.01 b (21.81) | 0.76 ± 0.00 c (22.43) | 3.44 ± 0.03 a (21.75) |
| Petunidin 3′-glucoside | Nd | 0.12 ± 0.00 (10.58) | Nd |
| Petunidin 3′-glucoside acetate | Nd | Nd | 0.17 ± 0.02 (23.25) |
a Concentration in mg/100 g dry weight; tR, retention time; Nd, not determined. Results are means ± SD (n = 3). Different superscript letters (a,b,c) indicate a statistically significant difference between three onion waste extracts (p < 0.05) (Data S1).