TABLE 2.
Identified BFIs for milk or cheese selected by 1-by-2 OPLS-DA analysis in serum of healthy adults1
| Retention time, min | Adduct mass, Da/charge | Neutral mass, Da | Identification | HMDB ID | Adducts | Identification level2 | Food source of BFIs3 |
|---|---|---|---|---|---|---|---|
| 1.07 | 349.110 | 326.121 | Blood group H disaccharide* | HMDB06590 | +Na | 1 | Milk |
| 1.14 | 530.207 | 529.200 | Lewis A trisaccharide | HMDB06582 | +H, +Na | 1 | Milk |
| 1.02 | 219.047 | 196.058 | Galactonic acid/gluconic acid* | HMDB00565/HMDB00625 | +Na | 3 (hydroxy acid) | Milk |
| 1.07 | 162.076 | 161.068 | Aminoadipic acid* | HMDB00510 | +H, +2Na-H, +Na, +H-H2O | 1 | Cheese |
| 0.99 | 176.103 | 175.095 | Citrulline | HMDB00904 | +H, +2Na-H, +Na | 1 | Cheese |
| 1.18 | 219.134 | 218.127 | Valyl-threonine | HMDB29137 | +H, 2M+H | 1 | Cheese |
| 5.08 | 263.139 | 262.131 | Phenylalanyl-proline* | HMDB11177 | +H | 1 | Cheese |
| 6.55 | 206.081 | 205.074 | Indolelactic acid* | HMDB00671 | +H, +Na, +NH4, +2Na-H | 1 | Cheese |
| 1.07 | 116.071 | 115.063 | Proline | HMDB00162 | +H, +Na, +2Na-H | 1 | Cheese |
1
n = 10 subjects. The isomers galactonic acid and gluconic acid could not be differentiated. *BFIs also detected in urine. Postprandial kinetics in serum and urine are detailed in Supplemental Figures 7–15. BFI, biomarker of food intake; HMDB ID, Human Metabolome Database Identification number; OPLS-DA, orthogonal projections to latent structures discriminant analysis.
2
Identification levels: 1, identified by comparison to a pure reference; 3, putatively characterized compound classes.
3
Selected as a BFI when VIP score >1.5 in 1-by-2 OPLS-DA analyses.