Table 2. Structural elucidation and identification of the retained beef associated colonic metabolites.
| Metabolites (HMDB) | RT | Matching fragments | ||
|---|---|---|---|---|
| Sample | Standard | Metfrag | Standard | |
| But-2-enoic acid | 1.85 | NS | 1/15 | NS |
| 3-Hydroxybutyric acida | 1.78 | 2.21 | 3/15 | 8/15 |
| ( ± )-Furaneol | 2.83 | 5.71 | 2/15 | ND |
| Panto-a/mevalonolactone | 5.02 | 5.31 | 1/15 | 7/15 |
| 2-Hexenyl formate | 7.28 | NS | 3/15 | NS |
| 3-Dehydroxycarnitinec | 0.98 | NS | 3/15 | NS |
| Pentylbenzene | 9.81 | NS | 2/15 | NS |
| Indoleacetaldehyde | 4.54 | NS | 1/15 | NS |
| 2-Phenylpropionaldehyde dimethyl acetal | 10.42 | NS | 1/15 | NS |
| 4-Pyridoxic acida | 6.59 | 3.06 | 1/15 | ND |
| Kynurenic acidb,c | 6.36 | 6.44 | 2/15 | 4/9 |
| L-Kynurenineb,c | 4.25 | 4.07 | 8/15 | 14/15 |
| L-Kynurenineb,c | 4.19 | 4.06 | 2/15 | 9/15 |
| Spermic acid 1 | 0.78 | NS | 6/15 | NS |
| N′-/L-formylkynureninec | 4.76 | NS | 6/15 | NS |
| N′-/L-formylkynureninec | 4.77 | NS | 6/15 | NS |
| Hexanoylcarnitinea | 7.87 | 8.44 | 1/15 | 3/15 |
| Succinyl-/methylmalonylcarnitine | 1.57 | NS | NA | NS |
| Glutarylcarnitineb | 2.64 | 2.69 | NA | 5/15 |
| Saccharopine | 1.18 | NS | 8/15 | NS |
| 15 (16)-epODE | 9.89 | NS | 5/15 | NS |
| 9 (S)-HPODE | 10.29 | NS | 6/15 | NS |
| 9, 10/12,13-TriHOME | 9.89 | NS | 3/15 | NS |
| Dityrosineb,c | 2.05 | 2.18 | 4/15 | 3/15 |
RT = retention time; NS = no standard available; NA = not applicable; ND = not determined.
Standard purchased, but amismatch in retention time (>0.20 min) or bmatching retention time (<0.20 min), cmetabolites potentially involved in red meat-associated diseases (e.g. CRC, diabetes mellitus and cardiovascular diseases).