Properties of complex composites

Generally, aqueous mixtures of polysaccharides and proteins are unstable at a certain concentration, and attractive or repulsive interactions occur, leading to phase separation [4], as shown in Fig. 3.5. For example, aqueous solutions of mixtures of vegetable proteins and polysaccharides can interact by coacervation and /or thermodynamic incompatibility [24]. 

Attraction interactions between positively charged proteins and the negatively charged pectins can lead to gelling, coacervation, or multilayer formation. These processes are the result of the overall stability of colloidal systems, which depend on both the individual properties of the components and the nature and strength of their interactions [15]. For HDE pectins, the hydrophobic forces are transcendental in complexating with protein [35]. 

Using a model complex of bovine albumin/beet pectin, a dependency on pH and ionic strength is set to achieve the interaction 

The solubility of proteins near their isoelectric point environments can be improved by complexation with charged polysaccharide such as pectin, mainly due to electrostatic interactions. It was found that at pH values between 4 and 5, near the isoelectric point of soy protein, the protein particles have a lower net charge, causing aggregation, having no electrostatic repulsion forces, hydrophobic interactions are dominant [32]. 

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