ARS | Publication request: Beta-Lactoglobulin Dextran Conjugates; the Effect of Polysaccharide Size on Emulsion Stability

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 3, 2004
Publication Date: January 1, 2005
Citation: Dunlap, C.A., Cote, G.L. 2005. Beta-lactoglobulin dextran conjugates; the effect of polysaccharide size on emulsion stability. Journal of Agricultural and Food Chemistry. 53:419-423.

Interpretive Summary: Carbohydrate polymers were conjugated to a common milk protein to improve the functional properties of the protein. Proteins found in milk are commonly used as emulsifiers in food products. The new conjugates demonstrated improved performance as food emulsifiers. Simulated salad dressing tests showed the conjugates were effective stabilizers, which may find applications in the food industry.

Technical Abstract: A series of dextrans and ß-lactoglobulin were covalently conjugated and screened for their ability to stabilize oil-in-water emulsions. Dextrans with the molecular weight of 19.6 kDa, 87 kDa, 150 kDa, 500 kDa, and 2000 kDa were attached to ß-lactoglobulin via the Maillard reaction. The conjugates were then purfied and evaluated as emulsifiers under neutral conditions. Emulsifying activity was determined by monitoring oil droplet size over time. Adsorption of the conjugates to the droplet surface was characterized by determining the protein surface load. The results show that increasing polysaccharide size increases emulsifying activity up to 150 kDa before leveling off. Conversely, surface protein density remains constant until 150 kDa, before decreasing with polysaccharide size. A model is presented to interpret the results.