Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection.
Level 5 - mechanism / opinion, no new human data
Analytical chemistry/bench study with no human subjects (graded Level 5 by clinical CEBM criteria).
PubMed 33138259 · doi:10.3390/molecules25215025
What was done
The authors developed and validated a rapid ultra-high performance liquid chromatography (UHPLC) method with fluorescence detection (excitation 280 nm, emission 360 nm) using a reversed-phase column and 5-methyl-l-tryptophan as an internal standard to quantify total tryptophan (TRP) in yoghurt. The chromatographic separation utilized a linear gradient of acetonitrile in water over an 8.0-minute run time. The method was then applied to determine TRP concentrations in commercial yoghurt samples derived from different animal species.
What was found
The analytical method achieved a run time of 8.0 minutes, with a limit of detection (LOD) of 0.011 ng/µL and a limit of quantification (LOQ) of 0.029 ng/µL. Testing of commercial yoghurts showed total tryptophan concentrations ranging from 35.19 mg/100 g in goat yoghurt to 121.97 mg/100 g in cow Greek-style yoghurt.
Why it matters
The method provides a rapid, sensitive analytical tool for measuring total tryptophan content in dairy products. This facilitates quality control and precise dietary assessment of an essential amino acid involved in protein synthesis and serotonin/kynurenine metabolic pathways.
Limits
This is purely a food-chemistry analytical validation study and provides no human metabolic, bioavailability, or clinical outcome data. The abstract does not report the total number of commercial yoghurt samples analyzed, the recovery rates, precision metrics (such as relative standard deviation), or specific sample preparation and hydrolysis steps used to release bound tryptophan.
Cited by
- supports Greek yogurt contains high amounts of the amino acid tryptophan.