Polysaccharide-lipid interactions

Le Meste, M., Tainturier, P., Gelin, J.-L. (1997). Lipid-protein interactions — consequences for surface activity in food emulsions. In Dickinson, E., Bergenstahl, B. (Eds). Food Colloids Proteins, Lipids and Polysaccharides, Cambridge, UK Royal Society of Chemistry, pp. 185-200. 

The monolayer technique is extremely significant and has numerous applications. With a system such as a monolayer, we have the realization of a simple molecular functional unit. In other words, it is a system whose properties are determined by an orderty arrangement of molecules, i.e., the molecules form a team and the stem behaves differently from an independoit molecule. Such functional systems are often encovmtered in biological structures, for example, the proteins interact with lipid, polysaccharides and with other interfaciaUy-boimd compoimds. In fact, the whole living body is a functional unit where varied molecules interact and cooperate with each other. 

It is important to understand the characteristic interactions involved at an interface containing each of the main types of surface-active molecules, i.e., biopolymers (proteins, polysaccharides) and low-molecular-weight surfactants (lipids). But that is not the whole story. In real food systems there are almost always mixed ingredients at the interface. So it is necessary to understand what sorts of mixed interfacial structures are formed, and how they are influenced by the intermolecular interactions. 

In Part Four (Chapter eight) we focus on the interactions of mixed systems of surface-active biopolymers (proteins and polysaccharides) and surface-active lipids (surfactants/emulsifiers) at oil-water and air-water interfaces. We describe how these interactions affect mechanisms controlling the behaviour of colloidal systems containing mixed ingredients. We show how the properties of biopolymer-based adsorption layers are affected by an interplay of phenomena which include selfassociation, complexation, phase separation, and competitive displacement. 

Hydrogen bonds and ionic, hydrophobic (Greek, water-fearing ), and van der Waals interactions are individually weak, but collectively they have a very significant influence on the three-dimensional structures of proteins, nucleic acids, polysaccharides, and membrane lipids. 

Fourteen chapters, each by a different author, cover (at an advanced level) the structure of water and its interactions with proteins, nucleic acids, polysaccharides, and lipids. 

This subject has been of continuing interest for several reasons. First, the present concepts of the chemical constitution of such important biopolymers as cellulose, amylose, and chitin can be confirmed by their adequate chemical synthesis. Second, synthetic polysaccharides of defined structure can be used to study the action pattern of enzymes, the induction and reaction of antibodies, and the effect of structure on biological activity in the interaction of proteins, nucleic acids, and lipides with polyhydroxylic macromolecules. Third, it is anticipated that synthetic polysaccharides of known structure and molecular size will provide ideal systems for the correlation of chemical and physical properties with chemical constitution and macromolecular conformation. Finally, synthetic polysaccharides and their derivatives should furnish a large variety of potentially useful materials whose properties can be widely varied these substances may find new applications in biology, medicine, and industry. 

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