Skip to main content

Advertisement

SpringerLink
Log in

Operationally defined solubilization of copper and iron in human saliva and implications for metallic flavor perception

  • Original paper
  • Published:
European Food Research and Technology Aims and scope Submit manuscript

Abstract

Metals such as copper and iron cause unpleasant taste perceptions. Metallic compounds come in contact with saliva before delivery to taste receptors. Therefore, it is assumed that interactions between saliva and metallic compounds affect the perceptions of metals. The aim of this study was to determine the solubilization of metals in saliva and to examine whether or not perceptions of metallic flavor are influenced by metal solubility in saliva. Ten trained panelists evaluated the sourness, bitterness, astringency, electric sensation, and rusty nail-like retronasal aroma of copper sulfate (CuSO4·5H2O, Cu) and ferrous sulfate (FeSO4·7H2O, Fe) dissolved in ultrapure water at different concentrations. Total and soluble metals were measured in the subjects’ saliva collected after tasting the samples using an inductively coupled plasma spectrometer. Approximately, 4.5–6.4% of Fe and 4.0–6.6% of Cu were retained in the saliva after expectoration. The proportion of soluble metal to total metal retained in saliva decreased from 0.68 to 0.29 for Cu and 0.019 to 0.0016 for Fe, as the metal concentration increased. In particular, Fe was solubilized in saliva at a maximum level of 4.5–4.6 μM, regardless of the metal concentration of the solution. The perceived intensities of sensory attributes showed positive linear relationships with log concentrations of total Cu, soluble Cu, and total Fe, but they did not have any relationship with soluble Fe. These results indicate that sensory perceptions of Fe were influenced mainly by the total Fe retained in saliva, whereas the perception of Cu was affected by soluble Cu as well as total Cu.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others

References

  1. Zacarias I, Yanez CG, Araya M, Oraka C, Olivares M, Uauy R (2001) Determination of the taste threshold of copper in water. Chem Senses 26:85–89

    Article  CAS  Google Scholar 

  2. Keast RSJ (2003) The effect of zinc on human taste perception. J Food Sci 68:1871–1877

    Article  CAS  Google Scholar 

  3. Hettinger TP, Myers WE, Frank ME (1990) Role of olfaction in perception of non-traditional ‘taste’ stimuli. Chem Senses 15:755–760

    Article  Google Scholar 

  4. Lawless HT, Schlake S, Smythe J, Lim J, Yang H, Chapman K, Bolton B (2004) Metallic taste and retronasal smell. Chem Senses 29:25–33

    Article  CAS  Google Scholar 

  5. Lawless HT, Stevens D, Chapman K, Kutz A (2005) Metallic taste from electrical and chemical stimulation. Chem Senses 30:185–194

    Article  CAS  Google Scholar 

  6. Lim J, Lawless HT (2005) Oral sensations from iron and copper sulfate. Physiol Behav 85:308–313

    Article  CAS  Google Scholar 

  7. Lim J, Lawless HT (2005) Qualitative differences of divalent salts: multidimensional scaling and cluster analysis. Chem Senses 30:719–726

    Article  CAS  Google Scholar 

  8. Lim J, Lawless HT (2006) Detection thresholds and taste qualities of iron salts. Food Qual Prefer 17:513–521

    Article  Google Scholar 

  9. Yang HHL, Lawless HT (2005) Descriptive analysis of divalent salts. J Sens Stud 20:97–113

    Article  Google Scholar 

  10. Yang HHL, Lawless HT (2006) Time-intensity characteristics of iron compounds. Food Qual Prefer 17:337–343

    Article  Google Scholar 

  11. Stevens DA, Smith RF, Lawless HT (2006) Multidimensional scaling of ferrous sulfate and basic tastes. Physiol Behav 87:272–279

    Article  CAS  Google Scholar 

  12. McClure ST, Lawless HT (2007) A comparison of two electric taste stimulation devices. Physiol Behav 92:658–664

    Article  CAS  Google Scholar 

  13. Epke EM, Lawless HT (2007) Retronasal smell and detection thresholds of iron and copper salts. Physiol Behav 92:487–491

    Article  CAS  Google Scholar 

  14. Stevens DA, Baker D, Cutroni E, Frey A, Pugh D, Lawless HT (2008) A direct comparison of the taste of electrical and chemical stimuli. Chem Senses 33:405–413

    Article  Google Scholar 

  15. Epke EM, McClure ST, Lawless HT (2009) Effects of nasal occlusion and oral contact on perception of metallic taste from metal salts. Food Qual Prefer 20:133–137

    Article  Google Scholar 

  16. Glindemann D, Dietrich A, Staerk H, Kuschk P (2006) The smell of touched or pickled iron is not Fe. Angew Chem Int Edit 45(4242):7006–7009

    CAS  Google Scholar 

  17. Riera CE, Vogel SA, Simon SA, Coutre JI (2007) Artificial sweeteners and salts producing a metallic taste sensation activate TRPV1 receptors. Am J Physiol Reg I 293:R626–R634

    CAS  Google Scholar 

  18. Cuppett JD, Duncan SE, Dietrich AM (2006) Evaluation of copper speciation and water quality factors that affect aqueous copper tasting response. Chem Senses 31:689–697

    Article  CAS  Google Scholar 

  19. Hong JH, Duncan SE, Dietrich AM (2010) Effect of copper speciation at different pH on temporal sensory attributes of copper. Food Qual Prefer 21:132–139

    Article  Google Scholar 

  20. Jensen JN (2003) A problem-solving approach to aquatic chemistry. Wiley, Hoboken

    Google Scholar 

  21. Hong JH, Duncan SE, Dietrich AM (2009) Ultrafiltration as a tool to study binding of copper to salivary proteins. Food Chem 113:180–184

    Article  CAS  Google Scholar 

  22. Hong JH, Duncan SE, Dietrich AM, O’Keefe SF, Eigel WN, Mallikarjunan K (2009) Interaction of copper and human salivary proteins. J Agr Food Chem 57:6967–6975

    Article  CAS  Google Scholar 

  23. Hong JH, Duncan SE, Dietrich AM, O’Keefe SF (2010) Evaluation of the operationally defined soluble, insoluble, and complexing copper consumed through drinking water in human saliva. Eur Food Res Technol 231:977–984

    Article  CAS  Google Scholar 

  24. Kallithraka S, Bakker J, Clifford MN (1998) Evidence that salivary proteins are involved in astringency. J Sens Stud 13:29–43

    Article  Google Scholar 

  25. Sarni-Manchado P, Cheynier V, Moutounet MJ (1999) Interactions of grape seed tannins with salivary proteins. J Agr Food Chem 47:42–47

    Article  CAS  Google Scholar 

  26. Sarni-Manchado P, Canals-Bosch J, Mazerolles G, Cheynier V (2008) Influence of the glycosylation of human salivary proline-rich proteins on their interactions with condensed tannins. J Agr Food Chem 56:9563–9569

    Article  CAS  Google Scholar 

  27. Chapman KW, Lawless HT (2004) Correlation of instrumental measures of saliva turbidity and perceived astringency of metallic salts. 2004 IFT annual meeting abstract archive. 83G-6. http://ift.confex.com/ift/2004/teleprogram/meeting_2004.htm. Accessed 24 March 2011

  28. Lawless HT, Heymann H (1998) Sensory evaluation of food: Principles and practices. Chapman & Hall, New York, pp 28–39

    Google Scholar 

  29. Omur-Ozbek P (2008) Macromolecular reactions and sensory perception at the air-water-human interaface. PhD thesis. Virginia Tech, Blacksburg, VA. USA

  30. Francis CA, Hector MP, Proctor GB (2000) Precipitation of specific proteins by freeze-thawing of human saliva. Arch Oral Biol 45:601–606

    Article  CAS  Google Scholar 

  31. O’Mahony M, Rothman L, Ellison T, Shaw D, Buteau L (1990) Taste descriptive analysis: concept formation, alighment and appropriateness. J Sens Stud 5:71–103

    Article  Google Scholar 

  32. Mehansho H (2006) Iron fortification technology development: New approaches. J Nutr 136:1059–1063

    CAS  Google Scholar 

  33. Kiskini A, Argiri K, Kalogeropoulos M, Komaitis M, Kostaropoulos A, Mandala I, Kapsokefalou M (2007) Sensory characteristics and iron dialyzability of gluten-free bread fortified with iron. Food Chem 102:309–316

    Article  CAS  Google Scholar 

  34. Sreenath PG, Abhilash S, Ravishankar CN, Srinivasa Gopal TK (2008) Standardization of process parameters for ready-to-eat shrimp curry in tin-free steel cans. J Food Process Pres 32:247–269

    Article  Google Scholar 

  35. Venkateshwarlu G, Let MB, Meyer AS, Jacobsen C (2004) Chemical and olfactometric characterization of volatile flavor compounds in a fish oil enriched milk emulsion. J Agr Food Chem 52:311–317

    Article  CAS  Google Scholar 

  36. Campo MM, Enser M, Wood JD, Richardson RI (2006) Flavour perception of oxidation in beef. Meat Sci 72:303–311

    Article  CAS  Google Scholar 

  37. Tenovuo JO (1989) Human saliva: clinical chemistry and microbiology, vol I. CRC Press Inc, Boca Raton

    Google Scholar 

  38. Ericsson Y, Hardwick L (1978) Individual diagnosis, prognosis and counseling for caries prevention. Caries Res 12(Suppl 1):94–102

    Article  Google Scholar 

  39. Parvinen T (1985) Flow rate, pH, and lactobacillus and yeast counts of stimulated whole saliva in adults. Proc Finn Dent Soc 81:113–116

    CAS  Google Scholar 

  40. Mishra OP, Agarwal KN, Agarwal RMD (1992) Salivary iron status in children with iron deficiency and iron overload. J Trop Pediatrics 38:64–67

    CAS  Google Scholar 

  41. Vance DB (1994) Iron-the environmental impact of a universal element. Natl Environ J 4:24–25

    Google Scholar 

  42. Pohl P, Prusisz B (2006) Redox speciation of iron in waters by resin-based column chromatography. TrAC 25:909–916

    CAS  Google Scholar 

  43. Kawakami H, Dosako S, Nakajima I (1993) Effect of lactoferrin on iron solubility under neutral conditions. Biosci Biotech Bioch 57:1376–1377

    Article  CAS  Google Scholar 

  44. Bardow A, Madsen J, Nauntofte B (2000) The bicarbonate concentration in human saliva does not exceed the plasma level under normal physiological conditions. Clin Oral Invest 4:245–253

    Article  CAS  Google Scholar 

  45. Pohl P, Sergiel I (2009) Evaluation of the total content and the operationally defined species of copper in beers and wines. J Agr Food Chem 57:9378–9384

    Article  CAS  Google Scholar 

  46. Omur-Ozbek P, Dietrich AM (2011) Retronasal perception and flavor thresholds of iron and copper in drinking water. J Water Health 9:1–9

    Article  CAS  Google Scholar 

Download references

Acknowledgments

This work was supported by a National Research Foundation of Korea Grant funded by the Korean Government (NRF-2009-351-C00086), and the New Faculty Research Program J2011-0055 of Kookmin University in Korea.

Author information

Authors and Affiliations

  1. Department of Foods and Nutrition, Kookmin University, Seoul, 136-702, Republic of Korea

    Jae Hee Hong

  2. Department of Food Science and Engineering, Ewha Womans University, Seoul, 120-750, Republic of Korea

    Kwang-Ok Kim

Authors
  1. Jae Hee Hong
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Kwang-Ok Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Kwang-Ok Kim.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Hong, J.H., Kim, KO. Operationally defined solubilization of copper and iron in human saliva and implications for metallic flavor perception. Eur Food Res Technol 233, 973–983 (2011). https://doi.org/10.1007/s00217-011-1590-x

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00217-011-1590-x

Keywords

Search

Navigation