Carbohydrate colloids Carbohydrates

See also Biotechnology (Bioprocess Engineering) Carbohydrates Colloid Systems Genetics and Gene Science (Classical) and Industrial Biotechnology. 

In natural streambed biofilms, the biomass of colloidal carbohydrates was found to be 5 times greater than the biomass of bacteria inhabiting the biofilm (Hall and Meyer, 1998). The biofilm volume/bacterial volume ratio is much higher, because the fraction of the biofilm volume actually occupied... 

Alginic acid is a hydrophilic colloid carbohydrate that occurs naturally in the cell walls and intercellular spaces of various species of brown seaweed (Phaeophyceae). The seaweed occurs widely throughout the world and is harvested, crushed, and treated with dilute alkali to extract the alginic acid. 

The role of carbohydrate colloids in wine clarification and stability has been studied much more extensively. Pectic substances in wine foul filter layers (Castino and Delfini, 1984) during filtration. This phenomenon is particularly marked in tangential microfiltration (Section 11.5.2) (Feuillat and Bernard 1987 Serrano et al., 1988) as the carbohydrate colloid retention rate may be over 50%. A much higher proportion of AGPs than yeast mannoproteins is retained in this process (Brillouet et al., 1989 Belleville et al., 1990). 

Yeasts are the second major source of polysaccharides in wine. A great deal of research has been devoted to the structure of yeast cell walls (Volume 1, Section 1.2), but much less to the type of carbohydrate colloids released into wine. 

The presence of macromolecular colloids (carbohydrate polymers) may also affect the stability of association colloids. Carbohydrate polymers may either act as protective coUoids, preventing flocculation, or possibly destabilize the colloids and cause them to precipitate (Section 9.4.1). 

Definition Hydrophilic colloidal carbohydrate derived from brown seaweed, Phaeophyceae polysaccharide composed of p-d-mannuronic acid residues... 

Linear glycuronoglycan consisting mainly of P-(l-4) linked D-mannuronic and a-(l-4)hnked L-gultironic acid units in pyranose ring form. Hydrophilic colloidal carbohydrate extracted by the use of dilute alkali from natural strains of various species of brown seaweeds. 

Class of colloidal substances prepared from plants. Composed of complex carbohydrates and organic acids that swell in water. Also, a number of natural resins are gums. 

Somewhat in advance of the widespread usage of the colloidal connotation of Ostwald and others, investigators in a number of instances seem to have favored the view that cellulose, starch, rubber, etc., are polymeric, the term being used in much the same sense as it is used today. The idea that proteins and carbohydrates are polymeric goes back at least to Hlasiwetz and Habermann, who, in 1871, considered... 

More recently, Brauns and Seiler (12), (13) extracted native lignin from spruce wood and then homogenized the wood in a colloidal mill. A suspension of approximately one gram of colloidal wood per liter of water was obtained. After the colloidal wood was changed to a solid form, it was found that its cell structure was completely destroyed. However, extraction of this wood with ethyl alcohol at room temperature did not yield further quantities of native lignin. These investigators have also reported the isolation of a lignosulfonic acid-carbohydrate compound. 

The chemistry is both wide ranging and interesting. It involves carbohydrate chemistry, the chemistry of inorganic pigments, organic resins —both natural and synthetic—and many other organic and polymeric additives. The sheet formation process also involves a considerable amount of colloid and surface chemistry. Polymer chemistry and environmental and analytical chemistry also play an important part. 

Fiebrig, L, Varum, K.M., Elarding, S.E., Davis, S.S., and Stokke, B.T. Colloidal gold and colloidal gold labelled wheat germ agglutinin as molecular probes for identification in mucin/ chitosan complexes, Carbohydr. Polym., 33 91-99 (1997). 

---