αs-Casein-PE6400 Mixtures: Thermodynamics of Micelle Formation

Anne Kessler; Jochen Weiss; Cosima Stubenrauch

doi:10.3139/113.110385

Published by De Gruyter September 15, 2015

α_s-Casein-PE6400 Mixtures: Thermodynamics of Micelle Formation

α_s-Casein-PE6400-Mischungen: Thermodynamik der Mizellenbildung

Anne Kessler , Jochen Weiss and Cosima Stubenrauch

From the journal Tenside Surfactants Detergents

https://doi.org/10.3139/113.110385

Showing a limited preview of this publication:

Abstract

Micelles are increasingly used as carrier systems. In previous studies, we have shown that the blockcopolymers PEO₁₃-PPO₃₀-PEO₁₃ and α_s-casein form micelles at distinct temperature and concentration ranges. The aim of the study at hand was to determine the thermodynamics of this micelle formation by isothermal titration calorimetry (ITC). For α_s-casein, micelle formation was investigated as a function of temperature from 15 – 30 °C at pH = 6.6, while micelle formation of PE6400 and of mixtures of PE6400 with α_s-casein was studied from 29 – 31 °C. In addition, the influence of increasing α_s-casein mole fraction from 0.135 × 10⁻³ to 3.6 × 10⁻³ was examined at 30 °C. In case of α_s-casein, the standard experimental approach could be used while we developed a new experimental approach for PE6400 and for the mixture. The results show that the enthalpy of demicellization increases for α_s-casein and decreases for PE6400 with increasing temperature. In case of the mixtures, the enthalpy of demicellization was not influenced by either the temperature or the α_s-casein mole fraction. The results obtained for α_s-casein suggest that the micellization follows a “shell-model”. In the case of the mixtures, α_s-casein is likely to form the core of the micelle while the outer part appears to be composed of PE6400. The mixing properties were antagonistic, which was shown by comparing the enthalpies of PE6400 with those of the mixtures. The results show that ITC is a powerful tool to precisely determine micellization properties not only of the single but also of mixed surfactant systems.

Kurzfassung

Mizellen werden zunehmend als Trägersysteme (Carriersysteme) eingesetzt. In vorangegangenen Studien haben wir gezeigt, dass die Blockcopolymere PEO₁₃-PPO₃₀-PEO₁₃ und α_s-Casein in bestimmten Konzentrationsbereichen und bei einer bestimmten Temperatur Mizellen bilden. Ziel dieser Untersuchung ist, die Thermodynamik der Mizellenbildung mittels der isothermen Titrationskalorimetrie (ITC) zu bestimmen. Die Mizellenbildung von α_s-Casein wurde als Funktion der Temperatur zwischen 15 – 30 °C bei pH 6,6, die Mizellenbildung von PE6400 und von PE6400-Mischungen mit α_s-Casein in einem Temperaturbereich von 29 – 31 °C untersucht. Zusätzlich wurde der Einfluss des steigenden Molenbruchs von α_s-Casein im -Bereich von 0.135 × 10⁻³ bis 3.6 × 10⁻³ bei 30 °C ermittelt. Für α_s-Casein konnte die konventionelle experimentelle Herangehensweise verwendet werden. Für PE6400 und die Mischungen mit PE6400 entwickelten wir einen neuen experimentellen Ansatz. Die Ergebnisse zeigen, dass die Mizellenauflösungsenthalpie für α_s-Casein zu- und für PE6400 bei steigender Temperatur abnimmt. Für die Mischungen wird die Mizellenauflösungs-enthalpie weder von der Temperatur noch von dem α_s-Casein-Molenbruch beeinflusst. Die für α_s-Casein erhaltenen Resultate lassen darauf schließen, dass die Mizellenbildung einem „Schalenmodell“ (shell-model) folgt. In den Mischungen bildet α_s-Casein wahrscheinlich den Mizellkern, während das Mizellen-äußere aus PE6400 besteht. Die Eigenschaften der Mischung sind entgegenwirkend, was deutlich wird, wenn man die Enthalpie von PE6400 mit denen der Mischung vergleicht. Die -Ergebnisse zeigen, dass ITC ein aussagekräftiges Verfahren darstellt, mit dem man die Mizellenbildung nicht nur der Einzelkomponenten, sondern auch von Tensidmischsystemen bestimmen kann.

Key words: αs-Casein; blockcopolymers; PE6400; isothermal titration calorimetry; ITC; aggregate formation; thermodynamics

Stichwörter: αs-Casein; Blockcopolymere; PE6400; isotherme Titrationskalorimetrie; ITC; Aggregatbildung; Thermodynamik

*Correspondence address, Prof. Dr. Cosima Stubenrauch, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany, Tel.: +49-7 11 68 56 44 70, Fax: +49-7 11 68 56 44 43, E-Mail: cosima.stubenrauch@ipc.uni-stuttgart.de

Dr. Anne Kessler studied life science engineering and process engineering at the University of Karlsruhe and at the TU Dresden (Germany). She carried out a five-months internship at the Nestlé Deutschland AG in Ludwigsburg from October 2005 to February 2006 and received her diploma in 2008. From 2009 – 2014 she worked on her PhD thesis at the Institute of Food Science and Biotechnology at the University of Hohenheim under the supervision of Prof. Weiss and the co-supervision of Prof. Stubenrauch.

Prof. Dr. Jochen Weiss studied chemical engineering at the University of Karlsruhe and received his PhD in Food Science at the University of Massachusetts in 1999. From 1999 – 2004 he worked as an assistant/associate professor at the Department of Food Science and Technology, University of Tennessee. He went back to the University of Massachusetts where he worked from 2004 – 2008 as associate professor. Since 2008 he is professor and head of the department “Food Physics and Meat Science” at the University of Hohenheim (Germany). Furthermore, from 2011 – 2014 he was the Vice President of Research at the University of Hohenheim.

Prof. Dr. Cosima Stubenrauch studied chemistry at the universities of Münster and Freiburg and received her PhD in Physical Chemistry at the TU Berlin in 1997. After a postdoctoral year at the Université Paris Sud, she worked as an associate researcher and lecturer at the Institute of Physical Chemistry, University of Cologne, from 1999 to 2004. From 2005 to 2009 she worked at University College Dublin. Since 2009 she is professor and head of chair “Physical Chemistry of Condensed Matter” at the University of Stuttgart (Germany). Furthermore, since 2014 she is Dean of the Faculty Chemistry and since 2010 docent in Physical Chemistry in Thin Films at the KTH Royal Institute of Technology, Stockholm (Sweden).

References

1. Creamer, L. K., In: Milk proteins – Casein nomenclature, structure and association properties; Roginski, H., Ed.; Encyclopedia of Dairy Science; Academic Press, Amsterdam, 2004; pp 1895–1902.10.1016/B0-12-227235-8/00318-7Search in Google Scholar

2. Tanford, C.: The Hydrophobic effect: Formation of micelles and biological membranes; Krieger Publishing Company, Malabar, Florida, USA, 1991. 10.1002/pol.1980.130181008Search in Google Scholar

3. Cosgrove, T.: Colloid Science: Principles, Methods and Applications; Blackwell Publishing Ltd., Oxford, UK, 2005. 10.1002/9781444305395.fmatterSearch in Google Scholar

4. Portnaya, I., Ben-Shoshan, E., Cogan, U., Khalfin, R., Fass, D., Ramon, O. and Danino, D.: Self-assembly of bovine β-casein below the isoelectric pH. Journal of Agricultural and Food Chemistry56 (2008) 2192–2198. 10.1021/jf072630rSearch in Google Scholar PubMed

5. Portnaya, I., Cogan, U., Livney, Y. D., Ramon, O., Shimoni, K., Rosenberg, M. and Danino, D.: Micellization of bovine β-casein studied by isothermal titration microcalorimetry and cryogenic transmission electron microscopy. Journal of Agricultural and Food Chemistry54 (2006) 5555–5561. 10.1021/jf060119cSearch in Google Scholar PubMed

6. Bouchemal, K., Agnely, F., Koffi, A. and Ponchel, G.: A concise analysis of the effect of temperature and propanediol-1,2 on Pluronic F127 micellization using isothermal titration microcalorimetry. Journal of Colloid and Interface Science338 (2009) 169–176. 10.1016/j.jcis.2009.05.075Search in Google Scholar PubMed

7. Hildebrand, A., Garidel, P., Neubert, R. and Blume, A.: Thermodynamics of Demicellization of Mixed Micelles Composed of Sodium Oleate and Bile Salts. Langmuir20 (2004) 320–328. 10.1021/la035526mSearch in Google Scholar PubMed

8. Bouchemal, K., Agnely, F., Koffi, A., Djabourov, M. and Ponchel, G.: What can isothermal titration microcalorimetry experiments tell us about the self-organization of surfactants into micelles?Journal of Molecular Recognition23 (2010) 335–342. 10.1002/jmr.998Search in Google Scholar PubMed

9. Kessler, A., Menéndez-Aguirre, O., Hinrichs, J., Stubenrauch, C. and Weiss, J.: αs-Casein – PE6400 mixtures: Surface properties, miscibilities and self-assembly. Colloids and Surfaces B: Biointerfaces118 (2014) 49–56. 10.1016/j.colsurfb.2014.03.030Search in Google Scholar PubMed

10. Kessler, A., Menéndez-Aguirre, O., Hinrichs, J., Stubenrauch, C. and Weiss, J.: Properties of an αs-casein-rich casein fraction: Influence of dialysis on surface properties, miscibility, and micelle formation. Journal of Dairy Science96 (2013) 5575–5590. 10.3168/jds.2013-6788Search in Google Scholar PubMed

11. Kessler, A., Menéndez-Aguirre, O., Hinrichs, J., Stubenrauch, C. and Weiss, J.: α_s-Casein – PE6400 mixtures: A fluorescence study. Faraday Discussions166 (2013) 399–416. 10.1039/c3fd00102dSearch in Google Scholar

12. Portnaya, I., Khalfin, R., Kesselman, E., Ramon, O., Cogan, U. and Danino, D.: Mixed micellization between natural and synthetic block copolymers: β-casein and Lutrol F-127. Physical Chemistry Chemical Physics13 (2011) 3153–3160. 10.1039/c0cp01321hSearch in Google Scholar

13. Post, A. E., Ebert, M. and Hinrichs, J.: β-Casein as a bioactive precursor – processing for purification. Australian Journal of Dairy Technology64 (2009) 84–88.Search in Google Scholar

14. Kessler, A., Zeeb, B., Kranz, B., Menéndez-Aguirre, O., Fischer, L., Hinrichs, J. and Weiss, J.: Isothermal titration calorimetry as a tool to determine the thermodynamics of demicellization processes. Review of Scientific Instruments83 (2012) 105104. 10.1063/1.4754718Search in Google Scholar

15. Alexandridis, P., Zhou, D. and Khan, A.: Lyotropic liquid crystallinity in amphiphilic block copolymers: Temperature effects on phase behavior and structure for poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymers of different composition. Langmuir12 (1996) 2690–2700. 10.1021/la951025sSearch in Google Scholar

16. Bijma, K., Engberts, J. B. F. N., Blandamer, M. J., Cullis, P. M., Last, P. M., Irlam, K. D. and Soldi, L. G.: Classification of calorimetric titration plots for alkyltrimethylammonium and alkylpyridinium cationic surfactants in aqueous solutions. Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases93 (1997) 1579–1584. 10.1039/A607596GSearch in Google Scholar

17. Tadros, T. F.: Applied surfactants; Wiley-VCH, Weinheim, 2005. 10.1002/3527604812Search in Google Scholar

18. Alexandridis, P., Holzwarth, J. F. and Hatton, T. A.: Micellization of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) triblock copolymers in aqueous solutions: Thermodynamics of copolymer association. Macromolecules27 (1994) 2414–2425. 10.1021/ma00087a009Search in Google Scholar

19. Mikheeva, L. M., Grinberg, N. V., Grinberg, V. Y., Khokhlov, A. R. and De Kruif, C. G.: Thermodynamics of micellization of bovine β-casein studied by high-sensitivity differential scanning calorimetry. Langmuir19 (2003) 2913–2921. 10.1021/la026702eSearch in Google Scholar

20. O’Connell, J. E., Grinberg, V. Y. and De Kruif, C. G.: Association behavior of β-casein. Journal of Colloid and Interface Science258 (2003) 33–39. 10.1016/S0021-9797(02)00066-8Search in Google Scholar

21. Tai, M. and Kegeles, G.: A micelle model for the sedimentation behavior of bovine β-casein. Biophysical Chemistry20 (1984) 81–87. 10.1016/0301-4622(84)80007-1Search in Google Scholar

22. Kegeles, G.: A shell model for size distribution in micelles. Journal of Physical Chemistry83 (1979) 1728–1732. 10.1021/j100476a009Search in Google Scholar

23. Kausalya, N., Reddy, Fordham, P. J., Attwood, D. and Booth, C.: Association and surface properties of block-copoly(oxyethylene/oxypropylene/oxyethylene) L64. Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases86 (1990) 1569–72. 10.1039/FT9908601569Search in Google Scholar

24. Portnaya, I., Khalfin, R., Kesselman, E. and Danino, D.: Synergistic Effects in Mixed Micellization between Natural and Synthetic Block Copolymers. NSTI-Nanotech3 (2011) 221–224.Search in Google Scholar

Received: 2015-03-05

Accepted: 2015-06-02

Published Online: 2015-09-15

Published in Print: 2015-09-15

α_s-Casein-PE6400 Mixtures: Thermodynamics of Micelle Formation

Abstract

Kurzfassung

References

Journal and Issue

Articles in the same Issue