Abstract
Although exopolysaccharides (EPS) produced by lactic acid bacteria can be used to modulate the rheological and physical properties of fermented milk, the interactions between EPS and milk proteins in such complex system remain poorly understood. This work aimed to study the interaction between EPS with different structural characteristics and caseins in the absence or presence of whey proteins in a dairy model system simulating yoghurt conditions. The study was expected to highlight the contribution of whey proteins to the casein network and identify possible interactions of EPS with the casein network. Four starters were used: HC15/210R (control), HC15/291 (neutral, stiff, branched EPS), HC15/702074 (neutral, flexible, highly branched EPS), and 2104/210R (anionic, stiff, linear EPS). Fermentation was performed at 42 °C until the pH reached 4.6. Microstructure and rheological and physical properties (syneresis, elastic modulus, and apparent viscosity) were measured. The diversity of EPS functionalities depended on the specific structures of the EPS: stronger gels were formed with the anionic EPS from strain 2104 probably because of electrostatic interactions, although limitation of syneresis was more influenced by the neutrality and stiffness of the EPS backbone of strain 291. The sequential addition of casein and whey proteins to the dairy model system revealed their individual contribution to the microstructure of the protein network. This study showed that the rheological and physical properties of fermented milk can be modulated by the casein and whey protein concentrations and the use of different EPS with specific structural characteristics.
References
AOAC International (2000) Official methods in analytic of AOAC international. In: Horwitz DW (ed) Chapter 33: Dairy products, 17th edn. Maryland, pp 69–82
Ayala-Hernández I, Goff HD, Corredig M (2008) Interactions between milk proteins and exopolysaccharides produced by Lactococcus lactis observed by scanning electron microscopy. J Dairy Sci 91:2583–2590
Ayala-Hernández I, Hassan AN, Goff HD, Corredig M (2009) Effect of protein supplementation on the rheological characteristics of milk permeates fermented with exopolysaccharide-producing Lactococcus lactis subsp. cremoris. Food Hydrocoll 23:1299–1304
Brandrup J, Immergut EH, Grulke EA (2005) Polymer handbook. Wiley, New York
Doublier JL, Garnier C, Renard D, Sanchez C (2000) Protein–polysaccharide interactions. Curr Opin Colloid Interf Sci 5:202–214
Doleyres YL, Schaub L, Lacroix C (2005) Comparison of the functionality of exopolysaccharides produced in situ or added as bioingredients on yogurt properties. J Dairy Sci 88:4146–4156
Faber EJ, Kamerling JP, Vliegenthart JFG (2001) Structure of the extracellular polysaccharide produced by Lactobacillus delbrueckii subsp. bulgaricus 291. Carbohydr Res 331:183–194
Faber EJ, van Haaster DJ, Kamerling JP, Vliegenthart JFG (2002) Characterization of the exopolysaccharide produced by Streptococcus thermophilus 8S containing an open chain nononic acid. Eur J Biochem 269:5590–5598
Faber EJ, Zoon P, Kamerling JP, Vliegenthart JFG (1998) The exopolysaccharides produced by Streptococcus thermophilus Rs and Sts have the same repeating unit but differ in viscosity of their milk cultures. Carbohydr Res 310:269–276
Famelart M-H, Tomazewski J, Piot M, Pezennec S (2004) Comprehensive study of acid gelation of heated milk with model protein systems. Int Dairy J 14:313–321
Gentès M-C, St-Gelais D, Turgeon SL (2011) Gel formation and rheological properties of fermented milk with in situ exopolysaccharide production by lactic acid bacteria. Dairy Sci Technol 91:645–661
Girard M, Schaffer-Lequart C (2007) Gelation and resistance to shearing of fermented milk: role of exopolysaccharides. Int Dairy J 17:666–673
Girard M, Schaffer-Lequart C (2008) Attractive interactions between selected anionic exopolysaccharides and milk proteins. Food Hydrocoll 22:1425–1434
Harding LP, Marshall VM, Hernandez Y, Gu Y, Maqsood M, McLay N, Laws AP (2005) Structural characterisation of a highly branched exopolysaccharide produced by Lactobacillus delbrueckii subsp. bulgaricus NCFB2074. Carbohydr Res 340:1107–1111
Hassan AN, Ipsen R, Janzen T, Qvist KB (2003) Microstructure and rheology of yogurt made with cultures differing only in their ability to produce exopolysaccharides. J Dairy Sci 86:1632–1638
Jaubert A, Martin P (1992) Reverse-phase HPLC analysis of goat caseins. Identification of αs1 and αs2 genetic variants. Lait 72:235–247
Lamboley L, St-Gelais D, Champagne CP, Lamoureux M (2003) Growth and morphology of thermophilic dairy starters in alginate beads. J Gen Appl Microbiol 49:205–214
Lee WJ, Lucey JA (2004) Structure and physical properties of yogurt gels: effect of inoculation rate and incubation temperature. J Dairy Sci 87:3153–3164
Lucey JA, Tamehana M, Singh H, Munro PA (1998) Effect of interactions between denatured whey proteins and casein micelles on the formation and rheological properties of acid skim milk gels. J Dairy Res 65:555–567
Pierre A, Fauquant J, Le Graet Y, Piot M, Maubois JL (1992) Native micellar casein separation through cross flow membrane microfiltration. Lait 72:461–474
Robitaille G, Tremblay A, Moineau S, St-Gelais D, Vadeboncoeur C, Britten M (2009) Fat-free yogurt made using a galactose-positive exopolysaccharide-producing recombinant strain of Streptococcus thermophilus. J Dairy Sci 92:477–482
Ruas-Madiedo P, Hugenholtz J, Zoon P (2002) An overview of the functionality of exopolysaccharides produced by lactic acid bacteria. Int Dairy J 12:163–171
St-Gelais D, Roy D, Audet P (1998) Manufacture and composition of low fat Cheddar cheese from milk enriched with different protein concentrate powders. Food Res Int 31:137–145
Tamine AY, Robinson RK (1999) Yoghurt: science and technology. CRC, Cambridge
Tolstoguzov VB (1991) Functional properties of food proteins and role of protein–polysaccharide interaction: review. Food Hydrocoll 4:429–468
Tuinier R, Dhont JKG, De Kruif CG (2000) Depletion-induced phase separation of aggregated whey protein colloids by an exocellular polysaccharide. Langmuir 16:1497–1507
Tuinier R, Ten Grotenhuis E, Holt C, Timmins PA, De Kruif CG (1999) Depletion interaction of casein micelles and an exocellular polysaccharide. Phys Rev E-Stat Phys Plasmas Fluids Relat Interdiscip Top 60:848–856
Tuinier R, van Casteren WHM, Looijesteijn PJ, Schols HA, Voragen AGJ, Zoon P (2001) Effects of structural modifications on some physical characteristics of exopolysaccharides from Lactococcus lactis. Biopolymers 59:160–166
Turgeon SL, Beaulieu M, Schmitt C, Sanchez C (2003) Protein–polysaccharide interactions: phase-ordering kinetics, thermodynamic and structural aspects. Curr Opin Colloid Interf Sci 8:401–414
Turgeon SL, Plesca V (2009) Study of interactions between exopolysaccharides produced by strain Lactobacillus rhamnosus RW-9595M and milk proteins (Talk). Proceedings of the 5th International Symposium on Food Rheology and Structure, Zurich, Switzerland, pp 416–419
Van Calsteren M-R, Gagnon F, Guertin N, Moineau S, Lapointe G (2008) Structure determination of the exopolysaccharide produced by Lactococcus lactis subsp. cremoris strain SMQ461 (Poster). Glucidoc 2008, Saint-Valéry-sur-Somme, France
van Marle ME, Zoon P (1995) Permeability and rheological properties of microbially and chemically acidified skim-milk gels. Neth Milk Dairy J 49:47–65
Whistler RL, BeMiller JN (1997) In: Chemist AACC (ed) Polysaccharides. Eagan, Minnesota
Acknowledgments
This research was jointly funded by the research programs of the Fonds québécois de la recherche sur la nature et les technologies, Novalait Inc., the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec, and Agriculture and Agri-Food Canada. The principal author would like to thank the Canadian Dairy Commission, Novalait Inc., and the Fonds québécois de la recherche sur la nature et les technologies for her graduate scholarship. The authors would also like to thank Dr. Marie-Rose Van Calsteren and her team, from the Food Research and Development Centre, for their expertise and help with the validation of EPS structure by nuclear magnetic resonance and the determination of molecular weight.
Author information
Authors and Affiliations
Corresponding author
About this article
Cite this article
Gentès, MC., St-Gelais, D. & Turgeon, S.L. Exopolysaccharide–milk protein interactions in a dairy model system simulating yoghurt conditions. Dairy Sci. & Technol. 93, 255–271 (2013). https://doi.org/10.1007/s13594-013-0121-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13594-013-0121-x