Starch cellulose complexes

Most of the biomass used for energy is burned, either directly to provide heat or in a power station to provide electricity. Although biomass is a complex mixture of starch, cellulose, etc., in simple terms the burning process can be viewed as being represented by Equation 6.1. The CO2 output can be considered as being essentially neutral since a similar amount of CO2 is consumed in growing the biomass. 

Biomass is complex in composition, consisting of starch, cellulose, hemicellu-lose and lignin and small amounts of fats. In the past, typically only one of these constituents of the biomass was converted, and the rest discarded. The operations were thus highly inefficient when compared with fossil hydrocarbon refinery. 

In 1945, Ken, who was now Lecturer at Bristol University, was again invited by Hirst to move with him to Manchester University, this time as Senior Lecturer in Organic Chemistry. Once more, it became necessary for Hirst to concentrate his efforts on University and Government committee work. Ken Jones, therefore, took charge of the carbohydrate-research group, and supervised the completion of the explosives work. During this interval, Ken enjoyed the able collaboration of Dr. T. G. Halsall in studies on the structures of starch, cellulose, and glycogen, and on the oxidation of carbohydrates by periodate. The close association of Ken with Professor Hirst, which continued at Manchester University until 1948, was a tremendously fruitful one over 50 joint publications resulted from their research on complex polysaccharides. 

Several observations indicate the formation of starch-protein complexes. For instance, starch precipitates serum proteins of rabbit, horse, sheep, and chicken.962 This observation seemingly indicates that the complexation has a rather universal character. On the other hand, the type of bonding of proteins from Triticum durum and Triticum sativum is specific for each of these varieties.963 The observed effects may not be associated with complex formation, but they can instead be attributed to the destruction of micelles by dehydration, followed by agglomeration.964 As in the case of starch complexes with sugars, the effect of proteins and cellulose derivatives on starch gelation can be assumed to be the result of the competition for water in solution. As a consequence, swelling is perturbed.965-968... 

Solid-state cellulose can also be noncrystalline, sometimes called amorphous. Intermediate situations are also likely to be important but not well characterized. One example, nematic ordered cellulose has been described [230]. In most treatments that produce amorphous cellulose, the whole fiber is severely degraded. For example, decrystallization can be effected by ball milling, which leaves the cellulose as a fine dust. In this case, some crystalline structure can be recreated by placing the sample in a humid environment. Another approach uses phosphoric acid, which can dissolve the cellulose. Precipitation by dilution with water results in a material with very little crystallinity. There is some chance that the chain may adopt a different shape (a collapsed, sixfold helix) after phosphoric acid treatment. This was concluded because the cellulose stains blue with iodine (see Figure 5.12), similar to the sixfold amylose helix in the starch-iodine complex. 

Plants, in fact, can be viewed as a natural laboratory that synthesizes organic nutrition materials. Formaldehyde is produced in photosynthesis as a primary product. However, as formaldehyde is a poisonous compound, plants polymerize it into starch, cellulose and other complex compounds thereby transforming it into useful, non-toxic substances. The general equation of photosynthesis is sunlight... 

Besides a source of energy, organisms require a source of materials for biosynthesis of cellular matter and products in cell operation, maintenance and reproduction. These materials must supply all the elements necessary to accomplish this. Some microorganisms utilize elements in the form of simple compounds, others require more complex compounds, usually related to the form in which they ultimately will be incorporated in the cellular material. The four predominant types of polymeric cell compounds are the lipids (fats), the polysaccharides (starch, cellulose, etc.), the information-encoded polydeoxyribonucleic acid and polyribonucleic acids (DNA and RNA), and proteins. Lipids are essentially insoluble in water and can thus be found in the nonaqueous biological phases, especially the plasma and organelle membranes. Lipids also constitute portions ofmore complex molecules, such as lipoproteins and liposaccharides. Lipids also serve as the polymeric biological fuel storage. 

Complex side-reactions, including overoxidation, are likely to occur in the oxidations, and information on the mechanism of periodate oxidation and the periodate-oxidation products of starch, cellulose, xylan, and other polysaccharides have been discussed. Thus, the limit of periodate oxidation is not always that expected, and the formation of interresidue hemiacetal structures during the oxidation can cause an early halt. - It is not until these structures have been reduced that oxidation can proceed once more. Other oxidants, such as dichromate-sulfuric acid, dichromate-oxalic acid, and sodium hypochlorite (which cause more extensive reactions), have been investigated with respect to cellulose and periodate-oxidized cellulose. Further oxidation of 2,3-dialdehydocel-lulose with halogen peroxy acids gives 2,3-dicarboxycellulose. ... 

Carbohydrates Carbohydrates are a major source of energy for humans and are present in all foods (grains, vegetables, fruits, and milk), and vary in form from simple monosaccharides (fructose, glucose, galactose, sorbitol) to oligosaccharides (maltose, sucrose, lactose, raffinose, stachyose, ver-bascose), and more complex polysaccharides (starch, cellulose, etc.). 

Dietary carbohydrates are often classified as simple or complex. Simple carbohydrates are the sugars we classified earlier as monosaccharides and disaccharides (Chapter 17). Complex carbohydrates consist essentially of the polysaccharides amylose and amylo-pectin, which are collectively called starch. Cellulose, another polysaccharide, is also a complex carbohydrate however, because it cannot be digested by humans, it serves a nonnutritive role as fiber. 

The enzyme-catalysed reactions that living organisms use to generate the energy they need and to prepare the molecules they require, are collectively termed metabolism . In anabolism, enzyme-catalysed reactions are used to make large complex molecules, for example the synthesis of starch, cellulose and proteins. Photosynthesis is an example of an anabolic reaction. These processes require an input of energy from ATP. In catabolism, nutrient molecules are hydrolysed under enzyme control to provide smaller and simpler molecules for synthesis and also to supply energy (to convert ADP back to ATP). 

Elution of parafHn oil-impregnated starch thin-layer with acetone-conc. acetic acid (30 20, by vol) resulted in a separation of all the above mentioned compounds except K3, K4, and K5, which migrated as a single spot with the front. Under these conditions, untreated talc and impregnated starch, cellulose, or talc were complementary systems for the separation of this complex mixture of fat-soluble vitamins. 

Similarly, the biodegradation process affects more complex organic molecules such as natural polymers (starch, cellulose and so on) and some man-made polymers. This is indeed the case of biodegradable polymers used for the production of plastic articles that have been designed with the aim of being biodegraded in the soil or in composting plants. 

In beer production process, barley is transformed into malt by steeping the grains in water and allowing them to germinate to break the complex molecules of starch, cellulose, and protein inside each grain so they can be used in the brewing process. This reduces the enzyme activity but increases color and flavor, and small quantities of these darker malts are used to provide the color and flavor of the final beer. 

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