Characterization of binding and bioaccessibility of Cr in Cr-enriched yeast by sequential extraction followed by two-dimensional liquid chromatography with mass spectrometric detection
- 191 Downloads
Sequential extraction (water, Driselase, protease XIV) and extraction with simulated gastric and intestinal fluids were proposed to characterize the binding and the bioaccessibility of chromium in two commercial food supplements obtained by incorporation of this element into yeast. Chromium in Cr-enriched yeast was found to be hardly extractable with water, Driselase, or simulated gastric fluid (recoveries of approximately 10–20%), but proteolysis or gastrointestinal fluid digestion released more than half of the chromium present. Fractionation with size-exclusion chromatography with Cr-specific detection by inductively coupled plasma mass spectrometry (ICP MS) allowed the distinction of two fractions: one below approximately 1 kDa and one 1–5 kDa; they contained the entirety of the released Cr with proportions varying as a function of the extracting solution and the origin of sample. When collected and investigated by reversed-phase high-performance liquid chromatography–ICP MS, the low molecular mass fraction was found to release Cr(III), whereas the heavier one showed most of Cr bound in fairly stable hydrophobic complexes. However, an attempt of their identification by electrospray ionization MS/MS and matrix-assisted laser desorption ionization MS was not successful.
KeywordsSpeciation Chromium Yeast
NK is grateful for the financial support granted by the Royal Golden Jubilee Ph.D. Program of the Thailand Research Fund and to the Center of Excellence for Innovation in Chemistry (PERCH-CIC) of the Commission on Higher Education (Thailand). NK also acknowledges the financial support of the French Ministry of Foreign Affairs. The help of Dr. Katarzyna Bierla and Dr. Hugues Preud’homme at different stages of this study is acknowledged.
- 2.Anderson RA (1998) J Am Coll Nutr 17:548–555Google Scholar
- 3.Mertz W (1993) J Nutr 123:626–633Google Scholar
- 4.Institute of Medicine FaNB (2001) Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. National Academy Press, Washington, DCGoogle Scholar
- 16.Yamamoto A, Wada O (1995) Chromium–protein interactions. In: Berthon G (ed) Handbook of metal–ligand interactions in biological fluids. Marcel Dekker, New YorkGoogle Scholar
- 17.Lay PA, Levina A (2004) Chromium. In: McCleverty JA, Meyer TJ (eds) Comprehensive coordination chemistry II. Elsevier, AmsterdamGoogle Scholar