Table 2.
Overview of the validation criteria for candidate intake biomarkers for banana and tropical fruitsa
| Food item | Metabolites | Biofluid | Q1 | Q2 | Q3a | Q3b | Q4 | Q5 | Q6 | Q7 | Q8 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Banana | 5-Hydroxyindole acetic acid | Plasma | Y | U | Y | U | U | U | Y | Y | U |
| Banana | 5-Hydroxyindole acetic acid | Urine | Y | U | Y | U | U | U | Y | Y | U |
| Banana | 3-Methoxytyramine sulfate | Plasma | Y | U | U | U | Y | U | U | U | U |
| Banana | Dopamine sulfate | Plasma | Y | U | Y | U | Y | U | Y | Y | U |
| Banana | Dopamine sulfate | Urine | Y | Y* | Y | U | U | U | Y | Y | U |
| Banana | Methoxyeugenol glucuronide | Urine | Y | Y* | Y | U | U | U | U | U | U |
| Banana | Salsolinol sulfate | Urine | Y | Y* | Y | U | U | U | U | Y | U |
| Banana | 6-OH-MTβC sulfate | Urine | Y | Y* | U | U | U | U | U | U | U |
| Banana | Methoxyeugenol glucuronide + Dopamine sulfate | Urine | Y | Y* | Y | U | Y | Y | U | U | U |
| Banana | Methoxyeugenol-glucuronide + Dopamine sulfate + Salsolinol sulfate | Urine | Y | Y* | Y | U | Y | Y | U | U | U |
| Banana | Methoxyeugenol glucuronide + Dopamine sulfate + 6-OH-MTβC sulfate + 2-isopropylmalic acid | Urine | Y | Y* | Y | U | Y | Y | U | U | U |
| Banana | Methoxyeugenol glucuronide + Dopamine sulfate + Salsolinol sulfate + Xanthurenic acid + 6-OH-MTβC sulfate | Urine | Y | Y* | Y | U | Y | Y | U | U | U |
| Avocado | Perseitol | Urine | Y | U | Y* | U | U | U | U | U | U |
| Avocado | Mannoheptulose | Urine | Y | U | Y* | U | U | U | U | U | U |
| Watermelon | Citrulline | Plasma | Y | U | U | U | U | U | U | U | U |
| Watermelon | Citrulline | Urine | Y | U | U | U | U | U | U | U | U |
aQuestions related to each of the validation criteria: Q1. Is the marker compound plausible as a specific BFI for the food or food group (chemical/biological plausibility)?, Q2. Is there a dose-response relationship at relevant intake levels of the targeted food (quantitative aspect)?, Q3. Is the biomarkers kinetics described adequately to make a wise choice of sample type, frequency and time window (time-response) [a single-meal time-response relationship, b: repeated intakes have]?, Q4. Has the marker been shown to be robust after intake of complex meals reflecting dietary habits of the targeted population (robustness)?, Q5. Has the marker been shown to compare well with other markers or questionnaire data for the same food/food group (reliability)?, Q6. Is the marker chemically and biologically stable during bio specimen collection and storage, making measurements reliable and feasible (stability)?, Q7. Are analytical variability (CV %), accuracy, sensitivity, and specificity known as adequate for at least one reported analytical method (analytical performance)?, Q8. Has the analysis been successfully reproduced in another laboratory (reproducibility)?
Y yes the criterion is fulfilled, Y* the criterion is partially fulfilled but requires further investigation, N no the principle has not been fulfilled after investigation, U unknown; further data is required to determine the validation of the criterion, 6-OH-MTβC sulfate 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-β-carboline sulfate