TY - JOUR
T1 - The effect of glycosylation on the interfacial properties of bovine caseinomacropeptide
AU - Kreuß, Markus
AU - Strixner, Thomas
AU - Kulozik, Ulrich
N1 - Funding Information:
The authors would like to thank Annette Bruemmer-Rolf for her highly valued contribution in the experimental phase of the work. The authors are grateful for the financial support of the “Bundesministerium für Wirtschaft und Arbeit (BMWA)”, the “Arbeitsgemeinschaft industrieller Forschungs-vereinigungen”, “Otto von Guericke e.V.” (AiF) and the “Forschungskreis der Ernährungsindustrie (FEI)” within the project AiF-FV 15187 N.
PY - 2009/10
Y1 - 2009/10
N2 - The two major fractions of bovine caseinomacropeptide (CMP), the glycosylated gCMP and non-glycosylated aCMP, were studied for their emulsifying properties. The main finding was that aCMP showed significantly better emulsifying properties than gCMP. While aCMP showed an emulsifying activity index (EAI) of 150.7 g/m2, gCMP achieved a value of 98.5 g/m2. Stability of emulsions was 1.4 times higher for aCMP as compared to gCMP. Droplet size measurements and creaming studies showed a strong influence of pH on both fractions with minimal emulsion stabilities at pH 4.1 (gCMP) and 4.9 (aCMP). Investigation of the flocculation behaviour and variations of the ionic strength indicate that the glycan side chains induce a combination of electric, steric and hydrophilic effects, preventing an ordered adsorption of gCMP molecules at the oil/water interface, while aCMP builds a stable network at the surface. For further elucidation, zeta potential measurements for both fractions were performed, resulting in isoelectric points of 3.15 for gCMP and 4.15 for aCMP in bulk solution. Finally, a hypothesis of surface adsorption of CMP is presented as a function of glycosylation and pH based on experimental data supported by an approach using protein modelling techniques.
AB - The two major fractions of bovine caseinomacropeptide (CMP), the glycosylated gCMP and non-glycosylated aCMP, were studied for their emulsifying properties. The main finding was that aCMP showed significantly better emulsifying properties than gCMP. While aCMP showed an emulsifying activity index (EAI) of 150.7 g/m2, gCMP achieved a value of 98.5 g/m2. Stability of emulsions was 1.4 times higher for aCMP as compared to gCMP. Droplet size measurements and creaming studies showed a strong influence of pH on both fractions with minimal emulsion stabilities at pH 4.1 (gCMP) and 4.9 (aCMP). Investigation of the flocculation behaviour and variations of the ionic strength indicate that the glycan side chains induce a combination of electric, steric and hydrophilic effects, preventing an ordered adsorption of gCMP molecules at the oil/water interface, while aCMP builds a stable network at the surface. For further elucidation, zeta potential measurements for both fractions were performed, resulting in isoelectric points of 3.15 for gCMP and 4.15 for aCMP in bulk solution. Finally, a hypothesis of surface adsorption of CMP is presented as a function of glycosylation and pH based on experimental data supported by an approach using protein modelling techniques.
KW - Caseinomacropeptide
KW - Emulsifying properties
KW - Interfacial conformation
KW - Protein glycosylation
KW - Structure-function relationship
KW - Zeta potential
UR - http://www.scopus.com/inward/record.url?scp=67349207877&partnerID=8YFLogxK
U2 - 10.1016/j.foodhyd.2009.01.011
DO - 10.1016/j.foodhyd.2009.01.011
M3 - Article
AN - SCOPUS:67349207877
SN - 0268-005X
VL - 23
SP - 1818
EP - 1826
JO - Food Hydrocolloids
JF - Food Hydrocolloids
IS - 7
ER -