Polysaccharides plant

Cellulose can be obtained from plants, algae, fungi, and some bacteria. The tuni-cates, a group of primitive vertebrates, are a species in the animal kingdom that 

Cellulose from a different source, bacterial cellulose, also known as microbial cellulose, has been the focus of recent research studies [30]. Microbial cellulose possesses some superior characteristics compared to plant cellulose, including high purity, waterholding capacity (aroxmd 1000%), crystallinity (around 90%), nanofibrilar network, impressive mechanical strength, and in-situ moldability [26,27]. The studies were related to use of microbial cellulose as a nanomaterial in controlled-release systems [30] and transdermal formulations [31]. 

Cellulose and some of its derivatives have very good binding properties in the wet granulation process. Various MCC grades have found wide use as binder in wet 

Soluble as well as insoluble cellulose ethers have been used in hydrophilic polymeric matrices thanks to their hydrophilicity nature and good gel-forming characteristics. Among cellulose ethers, HEC shows the highest swelling ability and hydration rate. However, HPMC enjoys the most common use in hydrophilic matrix applications thanks to its excellent swelling ability, good compressibility and fast hydration characteristics. Mixtures of cellulose ethers with other cellulose ethers or different polymers are used in controlled release systems [28]. 

In a study, low viscosity hydrophilic hydroxyl propyl methylcellulose ether premium polymer (HPMC E15 LV) was utilized in a drug formulation. Addition of HPMC E15 LV resulted in improvements in physical and compression characteristics and the drug release profile [29]. 

Two glucose polymers of plant origin are of special importance among the polysaccharides pi 4-linked polymer cellulose and starch, which is mostly al 4-linked. 

Cellulose, a linear homoglycan of pi 4-linked glucose residues, is the most abundant organic substance in nature. Almost half of the total biomass consists of cellulose. Some 40-50% of plant cell walls are formed by cellulose. The proportion of cellulose in cotton fibers, an important raw material, is 98%. Cellulose molecules can contain more than 10 glucose residues (mass 1-2 10 Da) and can reach lengths of 6-8 pm. 

Naturally occurring cellulose is extremely mechanically stable and is highly resistant to chemical and enzymatic hydrolysis. These properties are due to the conformation of the molecules and their supramolecular organization. The unbranched pi 4 linkage results in linear chains that are stabilized by hydrogen bonds within the chain and between neighboring chains (1). Already during biosynthesis, 50-100 cellulose molecules associate to form an elementary fibril with a diameter of 4 nm. About 20 such elementary fibrils then form a microfibril (2), which is readily visible with the electron microscope. 

Cellulose microfibrils make up the basic framework of the primary wall of young plant cells (3), where they form a complex network with other polysaccharides. The linking polysaccharides include hemicellulose, which is a mixture of predominantly neutral heterogly-cans (xylans, xyloglucans, arabinogalactans, etc.). Hemicellulose associates with the cellulose fibrils via noncovalent interactions. These complexes are connected by neutral and acidic pectins, which typically contain galac-turonic acid. Finally, a collagen-related protein, extensin, is also involved in the formation of primary walls. 

In the higher animals, including humans, cellulose is indigestible, but important as roughage (see p.273). Many herbivores (e.g., the ruminants) have symbiotic unicellular organisms in their digestive tracts that break down cellulose and make it digestible by the host. 

The starch found in amyloplasts forms an important source of nutritional energy in the human diet. A high proportion of the world s food energy is in the form of starch that is obtained from cultivated plants (see Chapter 1). 

It was further shown that several other organic compounds such as nitroal-kanes [10], thymol [11], r-butyl alcohol, and tetrachloroethane [12,13] will also form a precipitable complex with amylose. 

Amylose is a linear molecule containing three kinds of D-glucose residues (1) one reducing-end residue with a free hemiacetal hydroxyl group, substituted only at C-4 (2) many D-glucose residues substituted at C-1 and C-4 and (3) one nonreducing D-glucose residue substituted only at C-1 (see Fig. 6.3A). Because of the 

Organic molecules such as 1-butanol form a similar complex with amylose in which the 1-butanol molecules are complexed in the hydrophobic interior of the helix. These complexes have crystalline properties and produce X-ray diffraction patterns called a V-pattem [19] (see Fig. 6.6). Electron microscopy and electron diffraction studies have indicated that the complex is a folded helical chain with a lamellar structure [20-24]. The helical chain folds every 100 A, giving an antiparallel structure in which the helices are 13 A in diameter (see Fig. 6.4C). 

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Commercial applications for polysaccharides include their use as food additives, medicines and industrial products. Although plant polysaccharides (such as starch, agar and alginate) have been exploited commercially for many years, microbial exopolysaccharides have only become widely used over the past few decades. The diversity of polysaccharide structure is far greater in micro-organisms compared to plants and around 20 microbial polysaccharides with market potential have been described. However, microorganisms are still considered to be a rich and as yet underexploited source of exopolysaccharides. 

Pectin belongs to a family of plant polysaccharides in which the polymer backbone consists of (1— 4)-linked a-D-galacturonic acid repeating-units. Often, (1— 2)-linked a-L-rhamnose residues interrupt the regular polygalacturonate sequence. The high viscosity and gelling properties of pectins are exploited by the food and pharmaceutical industries. X-Ray studies on sodium pectate, calcium pectate, pectic acid, and pectinic acid (methyl ester of pectic acid) have disclosed their structural details. 

Yamadas group [85,86] has also taken a Japanese Kampo medicine consisting of many different plants as a starting point for identifying bioactive plant polysaccharides. They foimd in the Kampo medicine Juzen-Taiho-To, composed of many plants, several bioactive polysaccharides with effects in different test systems that may influence the immune system. A study like this can lead to the identification of the best possible source of the plants in the mixture that contain bioactive polysaccharides. 

Figure 9 from Paulsen BS (ed) Bioactive Carbohydrate Polymers. Yamada H (2000) Bioactive plant polysaccharides from Japanese and Chinese traditional herbal medicines , p 15-p24. Kluwer Academic Publishers, with permission from Springer. 

D-Xylose, which is one of the most abundant sugars in plant polysaccharides, is a rare component of bacterial polysaccharides. It is found in the LPS of Type 1 Neisseria gonorrhoeae strain" GC 6. L-Xylose and its 3-methyI ether are components of the LPS of Pseudomonas maltophila strain NCTC 10257, and are j -pyranosidic. The d- and L-sugars, and different methyl ethers of these, have also been found in the LPS of some photosynthetic bacteria."... 

A 3-deoxyheptulosaric acid has been found in the LPS from Acineto-bacter calcoaceticus NCTC 10305. Another acid of this class, 3-deoxy-o-/yxo-heptulosaric acid ° (30), is a component of a plant polysaccharide. One 4-deoxyhexulosonic acid, of unknown configuration, is known and is a component of the E. coli K3 capsular polysaccharide. "... 

J.F. Thibauit, M. Rinaudo, Proc. Int. workshop on "Plant Polysaccharides, Structure and Function" Nantes, France (1984) 214. 

In some cases pectinolytic enzymes have been associated with virulence and it is generally accepted that pectinolysis by these bacteria facilitates their entry and spread in plant tissue. In Rhizohium, these enzymes may play a role in the root infection process that precedes nodule formation (Hubbell et al 1978). A. irakense has never been reported to be pathogenic on plants. It can therefore be speculated that moderate and strictly regulated pectinolysis of A. irakense facilitates entry in the outer cortex of plants roots, since A. irakense has been isolated from surface-sterilized roots. It is likely that breakdown of plant polysaccharides by root colonizing bacteria can provide them with extra carbon source. 

The enzymic synthesis of D-Xylose isomerase has been found in Lactobacillus pento-... 

Nowadays there is scientific evidence that, besides plant polysaccharides and lignin, other indigestible compounds such as resistant starch, oligosaccharides, Maillard compounds, and phytochemicals—mainly polyphenols—can be considered DF constituents (Saura-Calixto and others 2000). Of these substances, resistant starch is a major constituent in cereals, whereas phytochemicals are the most important such substance in fruits and vegetables. Here, we address mainly polyphenols and carotenoids associated with DF in fruits and vegetables because of the important biological properties derived from them. 

This material is another plant polysaccharide. The source is the seeds of the carob tree (Ceratonia siliqua), also known as the locust bean tree. The trees grow around the Mediterranean and in California. An alternative name for the fruit is Saint John s Bread . An impure material called carob pod flour can be produced by just removing the hulls and milling the endosperms directly. An impure product like this will give a... 

Starch is one of the most abimdant plant polysaccharides and is a major source of carbohydrates and energy in the human diet (Zobel and Stephen, 1995). Starch is the most widely used hydrocolloid in the food industry (Wanous, 2004), and is also a widely used industrial substrate polymer. Total annual world production of starch is approximately 60 million MT and it is predicted to increase by additional approximately 10 million MT by 2010 (FAO, 2006b LMC International, 2002 S. K. Patil and Associates, 2007). Com/maize Zea mays L.), cassava (also known as tapioca—Manihot escu-lenta Crantn.), sweet potato Ipomoea batatas L.), wheat Triticum aestivum L.), and potato Solanum tuberosum L.) are the major sources of starch, while rice Oryza sativa L.), barley Hordeum vulgare L.), sago Cycas spp.), arrowroot Tacca leontopetaloides (L.) Kimtze), buckwheat Fagopyrum esculentum Moench), etc. contribute in lesser amounts to total global production. 

For monitoring the extent of polysaccharide hydrolysis, l.c. methods that sepeu ate and analyze the non-fermentable oligosaccharides (d.p. 3-30) derived from cellulose, hemicellulose, and pectins are useful, and have already been described (see Section III,l,c). For determination of the monosaccharide composition of completely hydrolyzed, plant polysaccharides, l.c. is especially useful and has been applied to the compositional analysis of hydrolyzed plant fiber,wood pulps,plant cell-walls,and cotton fibers.In these representative examples, the major sugars of interest, namely, glucose, xylose, galactose, arabinose, and mannose, have traditionally been difficult to resolve by l.c. The separa-... 

Dietary fibre was defined by Hugh TroweU as the plant polysaccharides and lignin which are resistant to hydrolysis by the digestive enzymes of humans . This definition lacks chemical precision, because non-flbrous pectins and gums are also present. The term nonstarch polysaccharide (NSP) is often preferred, although the term dietary fibre still persists. Unfortunately, NSP is also not satisfactory since some starch, known as resistant or par-... 

Phosphoric acid esters of the ketopentose D-ribulose (2) are intermediates in the pentose phosphate pathway (see p.l52) and in photosynthesis (see p.l28). The most widely distributed of the ketohexoses is D-fructose. In free form, it is present in fruit juices and in honey. Bound fructose is found in sucrose (B) and plant polysaccharides (e.g., inulin). 

Richards, G. N. Proc. Inti. Workshop on Plant Polysaccharides, Structure and Function Nantes, France, 9-11 July 1984, p.47-53. 

The important difference between a and 3 glycosidic bonds can be seen in the digestibility of the major plant polysaccharides cellulose and starch. 

Cox, G., and Feijo, J. 2004. Second harmonic imaging of plant polysaccharides. Proc. SPIE 5323 335-342. Microscopy in the biomedical sciences IV. 

The seven major flavonoids in these flours were isolated and identified as 3-0-glycosides of kaempferol and quercetin. The marked brown discoloration observed when LCP glanded cottonseed flour is used in a food product is caused by bound gossypol and at least two bound gossypol-like pigments. The brown color observed when glandless cottonseed flour is used in food is believed to be due to other phenolic constituents that are either insoluble polymers or are bound to the insoluble plant polysaccharides. 

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