Table 1.
Phenolic compounds determined in mandarin peel, control, and fortified wheat bread extracts. Data are expressed as mean ± standard deviation (n = 3).
| Compound (µg·g−1 DW) | Mandarin Peel | Control Bread |
2% (w/v) Fortified Bread |
4% (w/v) Fortified Bread |
|---|---|---|---|---|
| Gallic acid | 280 ± 6 a | 3.52 ± 0.01 c | 5.3 ± 0.5 b | 5.6 ± 0.5 b |
| Dihydroxybenzoic acid | n.d. | 0.29 ± 0.02 b | 0.42 ± 0.03 a | 0.44 ± 0.02 a |
| Caffeic acid | 38 ± 1 a | n.d. | n.d. | 0.75 ± 0.02 b |
| p-Coumaric acid | 72.4 ± 0.2 a | 3.50 ± 0.07 b | 2.28 ± 0.07 c | 2.34 ± 0.09 c |
| trans-Ferulic acid | 96.2 ± 0.5 a | 2.01 ± 0.03 c | 2.4 ± 0.2 bc | 2.57 ± 0.08 b |
| Rutin | 45 ± 4 a | 2.06 ± 0.01 c | n.a. | 7.3 ± 0.5 b |
| Naringin | 13 ± 1 a | n.d. | n.a. | 3.0 ± 0.2 b |
| Hesperidin | (6.2 ± 0.9) × 103 a | 1.1 ± 0.4 c | n.a. | 83 ± 3 b |
| Myricetin | 138 ± 20 a | n.d. | n.a. | 16.6 ± 0.9 b |
| Resveratrol | n.d. | 0.502 ± 0.001 a | 0.501 ± 0.001 a | 0.502 ± 0.002 a |
| Quercetin | 63 ± 3 a | n.d. | 22.8 ± 0.6 c | 33.3 ± 0.6 b |
| Kaempferol | 56 ± 8 | n.d. | n.d. | n.d. |
| Total Phenolic Acids | 489 ± 8 a | 9.3 ± 0.1 b | 10.7 ± 0.03 b | 12.4 ± 0.3 b |
| Total Flavonoids | 6400 ± 900 a/ 119 ± 10 a |
3.1 ± 0.4 d/ 0.502 ± 0.01 c |
22.7 ± 0.2 c | 141 ± 3 b/ 33.8 ± 0.2 b |
| Total Polyphenols | 6900 ± 940 a/ 607 ± 18 a |
12.9 ± 0.3 d/ 9.8 ± 0.1 c |
33.8 ± 0.2 c | 154 ± 3 b/ 46.3 ± 0.9 b |
Mean values with different letters in the same column indicate significant differences (p-value < 0.05) according to ANOVA and Fisher LSD test. n.d. = not detected; n.a. = not analyzed. Total values in italics exclude hesperidin, myricetin, rutin, and naringin. DW: dry weight (moisture content of: mandarin peels (38.8 ± 0.6)%, control bread (33.8 ± 0.3)%, 2% (w/v) enriched bread (29.4 ± 0.5)%, and 4% (w/v) enriched bread (28.8 ± 0.4)%).