Human Urinary Biomarker for Orange Juice Consumption

• To elucidate urinary biochemical markers for the consumption of orange juice.
  1H NMR urinary metabolite spectra will be acquired. Proline betaine will be quantified by peak integration of the resonance at 3.11ppm in the NMR spectrum.
  
  

• To investigate the kinetics of elucidated biomarker excretion over time.
  Excretion of proline betaine, as quantified from the 1H NMR spectrum of urine, will be plotted over time.
  
  

To elucidate the citrus fruit biomarker it needs to be ensured that all volunteers do not consume citrus fruits and foods potentially containing similar ingredients. Therefore it is necessary to ask volunteers to refrain from these foods by giving them dietary restrictions. Extensive literature research showed that some foods (such as grain legumes and brie cheese) may contain the same compound, but in much smaller amounts.

Days 1-3 will be on open diet but with dietary restrictions (no alcohol, cheese, fruits, ethnic foods such as Chinese and Indian food, grain legumes such as beans, lentils, peas and peanuts, and all kinds of sprouts (such as cress or alfalfa)). On day 2 a glass of orange juice (200ml) will be consumed in addition to the open diet. Urine collection will continue and stop on day 4 at 10 am.

During the study to minimise variation in biomarker excretion due to other beverages the participants beverage intake will be restricted to water and coffee.

All urine samples will then be analysed using high resolution NMR spectroscopy and mass spectrometry. Mathematical data analyses as well as the visual examinations of the NMR spectra will also be carried out to validate the presence of citrus fruit biomarkers.