Polysaccharides biopolymers based

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. 

Biopolymers are polymers produced by living organisms. They contain monomeric units that are covalently bonded to form larger structures. There are three main classes of biopolymers based on the differing monomeric units used and the structure of the biopolymer formed. Polynucleotides are long polymers which are composed of 13 or more nucleotide monomers, Polypeptides are short polymers of amino acids and polysaccharides are often linear bonded polymeric carbohydrate stmctures. Cellulose is the most coimnon organic compound and biopolymer on earth. About 33 percent of all plant matter is cellulose. The cellulose content of cotton is 90 percent and that of wood is 50 percent. 

Extensive research has been undertaken in blending different polymers to obtain new products having some of the desired properties of each component. Among protein- and polysaccharide-based green materials, those made from soy protein (Maruthi et al. 2014 Ghidelli et al. 2014 Behera et al. 2012) and starch (Katerinopoulou et al. 2014 Flores-Hemandez et al. 2014) have been extensively studied for and their physiochemical properties been analyzed. The literature review clearly shows that development of biodegradable biopolymer-based materials based on these materials can not only solve the white pollution problem but also ease the overdependence on petroleum resources. This chapter provides a brief overview of the preparation, properties, and application of cellulose fiber-reinforced soy protein-based and starch-based biocomposites. 

The sorption characteristics of various proteins for several volatile compounds are presented in Fig. 5.36. Ethanol is bound to the greatest extent, probably with the aid of hydrogen bonds. The binding of the nonpolar aroma compounds probably occurs on the hydrophobic protein surface regions. A proposal for the evaluation of data on the sorption of aroma volatiles on a biopolymer (protein, polysaccharide) is based on the law of mass action. When a biopolymer, B, has a group which attracts and binds the aroma molecule, A, then the following equation is valid ... 

A number of factors must be considered when selecting a suitable polysaccharide or combination of polysaccharides to fabricate a biopolymer-based delivery system. It is important to establish suitable environmental and solution conditions in which the polysaccharide molecules can associate with other polysaccharide or non-polysaccharide structure-forming molecules. To do so, one needs to know the physicochemical properties of the polysaccharides involved, such as helix-coil transition temperatures (for carrageenan, alginate,pectin) electrical properties (pKa values) sensitivity to specific monovalent or multivalent ions or susceptibility to enzyme or chemical reactions (BeMiller and Whistler, 1996). The most widely used carbohydrates for encapsulation purposes are probably alginates (Kailasapathy and Champagne, 2011 Kainmani et al, 2011), starch (Li et al, 2009) and its linear biopolymer amylose (Lalush et al, 2005). 

One ofthe main reasons for the catalysis of reactions represented by Equations (2)-(4) is based on the fact that there was no j ellification ofthe solutions with biopolymers in the neutral region after a month. When the processes could also proceed with the addition of an acid or alkali in the absence of biopolymers, one could observe a drastic acceleration. The gelation time could be decreased from hours to a few minutes once polysaccharides and proteins were added. 

Different routes for converting biomass into chemicals are possible. Fermentation of starches or sugars yields ethanol, which can be converted into ethylene. Other chemicals that can be produced from ethanol are acetaldehyde and butadiene. Other fermentation routes yield acetone/butanol (e.g., in South Africa). Submerged aerobic fermentation leads to citric acid, gluconic acid and special polysaccharides, giving access to new biopolymers such as polyester from poly-lactic acid, or polyester with a bio-based polyol and fossil acid, e.g., biopolymers . 

Sugars/polysaccharides Unsaturated lipid compounds L-Amino acids/peptides Nucleotides, bases, etc. Biopolymers... 

As discussed in Section 3.1.6.1., natural biopolymers are useful chiral selectors, some of which are readily available they are constructed from chiral subunits (monomers), for instance, from L-amino acids or D-glucose. If synthetic chiral polymers of similar type are to be synthesized, appropriate chiral starting materials and subunits, respectively, must be found. Chiral polymers with, for example, a helical structure as the chiral element, are built using a chiral catalyst as chirality inducing agent in the polymerization step. If the chirality is based on a chiral subunit, the chirality of the polymer is inherent, whereas if the polymer is constructed from chiral starting materials, chiral subunits are formed which lead to chirally substituted synthetic polymers that in addition may order or fold themselves to a supramolecular structure (cf. polysaccharides). 

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