Journal article
Effect of alginate size, mannuronic/guluronic acid content and pH on particle size, thermodynamics and composition of complexes with β-lactoglobulin
Department of Biotechnology and Biomedicine, Technical University of Denmark1
Enzyme and Protein Chemistry, Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark2
University of Copenhagen3
DuPont4
Protein Glycoscience and Biotechnology, Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark5
Department of Micro- and Nanotechnology, Technical University of Denmark6
Amphiphilic Polymers in Biological Sensing, Department of Micro- and Nanotechnology, Technical University of Denmark7
Roskilde University8
Alginate is an anionic polysaccharide capable of forming insoluble particles with proteins. Hence, alginate has potential as a protein carrier. However, the role of physical properties of the polysaccharide, such as degree of polymerization (DPn) and mannuronic/guluronic acid ratio, remains to be fully explored.
Particle formation of a high and a low molar mass alginate (ALG) with β-lactoglobulin (BLG) at pH 2-8 depends on the average DPn (HMW-ALG: 1.59·103; LMW-ALG: 0.23·103) and the mannuronic/guluronic acid ratio (1.0; 0.6) as supported by using ManA6 and GulA6 as models. Dynamic light scattering (DLS) showed that particles of BLG with either of the two ALGs have essentially the same hydrodynamic diameter (D H) at pH 3 and 2, while at pH 4 particles of LMW-ALG/BLG have larger D H than of HMW-ALG/BLG.
At pH 5-8 no significant particle formation was observed. ManA6 did not form insoluble particles at pH 2-8, while GulA6 formed insoluble particles, albeit only at pH 4. K d was approximately 10-fold higher for LMW-ALG/BLG than HMW-ALG/BLG and 3 orders of magnitude higher for an alginate trisaccharide/BLG complexation as determined by isothermal titration calorimetry (ITC).
The alginate trisaccharide did not form insoluble particles with BLG at pH 3 and 4, though interaction still occurred. δH app and molar stoichiometry of BLG in the complexes with the two ALGs differed by a factor of 7, as did their DPn, which thus affected the interaction strength, but not the BLG content.
At pH 4 the BLG content doubled in the particle due to BLG dimerization. The findings emphasize the importance of DPn, mannuronic/guluronic acid ratio and pH in formulations containing alginate/whey protein particles.
Language: | English |
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Year: | 2018 |
Pages: | 157-163 |
ISSN: | 18737137 and 0268005x |
Types: | Journal article |
DOI: | 10.1016/j.foodhyd.2017.09.001 |
ORCIDs: | 0000-0003-2658-414X , Stender, Emil G.P. , Khan, Sanaullah , Hachem, Maher Abou , Almdal, Kristoffer and Svensson, Birte |