Table 4.
Quantification and bioaccessibility percentage of the phenolic compounds of GERM.
| Phenolic compounds | Non-digested | Gastric phase | % Bioaccessibility | Intestinal phase | Bioaccessibility (%)9 |
|---|---|---|---|---|---|
| TSPC 1 | 0.43 ± 0.01a | 0.56 ± 0.02b | 132.19 | 0.61 ± 0.04c | 141.69 |
| 4-hydroxybenzoic acid (i1)2 | tr | tr | – | tr | – |
| 4-hydroxybenzoic acid (i2)2 | tr | tr | – | tr | – |
| Syringic acid3 | tr | tr | – | tr | – |
| Total hydroxybenzoic acids | tr | tr | – | tr | – |
| Trans-ferulic acid4 | 1.27 ± 0.41a | 3.34 ± 0.29b | 215.71 | 4.61 ± 0.17c | 300.52 |
| Caffeic acid5 | tr | tr | – | tr | – |
| Ferulic acid derivative (i1)4 | 14.16 ± 0.76b | 15.34 ± 0.51b | 108.62 | 5.11 ± 0.16a | 36.15 |
| Ferulic acid derivative (i2)4 | 5.35 ± 0.11a | 9.73 ± 3.64a | 182.69 | 5.60 ± 0.16a | 104.78 |
| 3-Feruloyl quinic acid4 | 4.89 ± 0.21b | 4.74 ± 1.20b | 97.44 | 0.56 ± 0.04a | 11.43 |
| 1-O-Sinapoyl-β-D-glucose (i1)4 | 11.25 ± 0.11 | nd | – | nd | – |
| 1-O-Sinapoyl-β-D-glucose (i2)4 | 3.87 ± 0.18 | nd | – | nd | – |
| 1-O-Sinapoyl-β-D-glucose (i3)4 | 0.52 ± 0.06 | nd | – | nd | – |
| Total hydroxycinnamic acids | 41.30 ± 1.20b | 33.15 ± 5.35b | 80.48 | 15.87 ± 0.36a | 38.46 |
| Apigenin-6-C-arabinoside-8-C-hexoside (i1)6 | 1.69 ± 0.02c | 0.89 ± 0.02a | 52.97 | 1.07 ± 0.02b | 63.19 |
| Apigenin-6-C-arabinoside-8-C-hexoside (i2)6 | 5.52 ± 0.08b | 4.59 ± 0.44a | 82.97 | 4.61 ± 0.12a | 83.41 |
| Apigenin-6-C-arabinoside-8-C-hexoside (i3)6 | tr | tr | – | tr | – |
| 5,7,4'-trihydroxy-3',5'-dimethoxy-flavone (tricin)7 | tr | tr | – | tr | – |
| Lucenin-1/3 (luteolin-6/8-C-xyloside-8/6-C-glucoside)6 | tr | tr | – | tr | – |
| Total flavones | 7.21 ± 0.10b | 5.48 ± 0.46a | 75.95 | 5.67 ± 0.15a | 78.68 |
| Formononetin (Glycosylated and methylated) (i1)8 | 1.51 ± 0.12 | nd | – | nd | – |
| Formononetin (Glycosylated and methylated) (i2)8 | 5.22 ± 0.04 | nd | – | nd | – |
| Total isoflavonoids | 6.73 ± 0.16 | nd | – | nd | – |
Data are mean values ± standard deviation of three replicates. Different lowercase letters in the same row indicate significant differences of means in different digestion phases (one-way ANOVA, post-hoc Duncan's test, p ≤ 0.05). i, isomer; nd, non-detected; tr, traces; TSPC, total soluble phenolic compounds. 1g gallic acid equivalents/100 g. 2mg 100/g 4-hydroxybenzoic acid (linearity range 0–3.75 μg/mL, R2 > 0.99). 3mg/100 g gallic acid (linearity range 0.1–8.33 μg/mL, R2 > 0.99). 4mg/100 g ferulic acid (linearity range 0–25 μg/mL, R2 = 1, LOD = 0.04 μg mL, LOQ = 0.12 μg/mL). 5mg/100 g caffeic acid (linearity range 0–2.77 μg/mL, R2 > 0.99, LOD = 0.16 μg/mL, LOQ = 0.47 μg/mL). 6mg/100 g vicenin-2 (linearity range 0–25 μg/mL, R2 = 1, LOD = 0.02 μg/mL, LOQ = 0.05 μg/mL). 7mg/100 g vitexin (linearity range 0–25 μg/mL, R2 = 1, LOD = 0.22 μg/mL, LOQ = 0.67 μg/mL). 8mg/100 g daidzein (linearity range 0–8.33 μg/mL, R2 = 1, LOD = 0.03 μg/mL, LOQ = 0.09 μg/mL). 9Bioaccessibility expressed as percentage was calculated as the ratio of free phenolic compounds released from food matrix during digestion and the initial content of free phenolic compounds in the wheat ingredients before digestion (values over 100% are indicative of increase in the bioaccessible amount of phenolic compounds in each digestion phase).