β-Lactoglobulin−Dextran Conjugates:  Effect of Polysaccharide Size on Emulsion Stability

Abstract

A series of dextrans and beta-lactoglobulin were covalently conjugated and screened for their ability to stabilize oil-in-water emulsions. Dextrans with the molecular mass of 19.6 kDa, 87 kDa, 150 kDa, 500 kDa, and 2000 kDa were attached to beta-lactoglobulin via the Maillard reaction. The conjugates were then purified and evaluated as emulsifiers under neutral conditions. The ability to stabilize emulsions 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 emulsion stability 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.

Bovine Serum Albumin-Sugar Conjugates through the Maillard Reaction: Effects on Interfacial Behavior and Emulsifying Ability

“…To improve functional properties of proteins including their emulsifying ability, chemical modifications have often been made. Over the past few years, there has been growing interest in the modification of proteins with sugars through the Maillard reaction [4][5][6][7][8][9][10][11][12][13][14] ; a complex network of non-enzymatic reactions between reducing sugars and protein amino groups (see ). At an early stage of the Maillard reaction, amino groups in proteins react with carbonyl groups of sugars to give 1-amino-1-deoxy-ketose, known as the Amadori compound 15) .…”

“…It has been reported that products of the Maillard reaction exhibit improved emulsifying and foaming ability in some cases. To enhance the efficiency of globular proteins as an emulsifier, polysaccharides have often been used to covalently connect with proteins by the Maillard reaction 4,[11][12][13][14] . When the protein-polysaccharide conjugates adsorb at the oil-water interface in emulsion, polysaccharide chains will protrude into the aqueous bulk and provide a protecting layer that prevents the coalescence and flocculation of oil droplets.…”

Improved heat stability of protein solutions and O/W emulsions upon dry heat treatment of whey protein isolate in the presence of low-methoxyl pectin

“…According to Oliver et al (Oliver, et al, 2006), Maillard reaction is a spontaneous and naturally occurring reaction between available amino groups from a protein with reducing sugar entities from polysaccharides, which involves the Amadori rearrangement (Dunlap & Côté, 2005;. Thus, during the Maillard reaction amino groups of the protein will be consumed and as a consequence the availability of the amino groups decreases.…”

Milk Protein–Polysaccharide Interactions

“…Because of their stable properties, this kind of bonding has been intentionally used to produce conjugated emulsifiers (Akhtar & Dickinson, 2003;Benichou et al, 2007;Dunlap & Côté, 2005;Neirynck et al, 2004;Shepherd et al, 2000;Song et al, 2002). In most of these studies, the covalent conjugation between proteins and polysaccharides has been achieved through the Maillard reaction.…”

“…Sunflower oil (20.0-wt%) Covalent conjugation providing better emulsion stability (Dunlap & Côté, 2005) 25. Lysozymes + Chitosan Corn oil (25.0-vol%) Covalent conjugate: Emulsion stability-High-molecular-type chitosan > Low molecular type (Song et al, 2002) being adsorbed to the surface of the oil droplet and the properties of a hydrophilic polysaccharide being highly hydrated by the aqueous phase.…”