Cellulose water content

Commercial bakeries and doughnut shops normally use a system that extrudes a batter from a reservoir directly into the deep fat fryer (Figure 5). In such a system the rheology of the batter is vitally important. The batter must flow and spread as needed. The major influence on the batter viscosity is the water content, which is around 70% of the flour or around 40% of the dry mix. Various gums are sometimes added to the dry mix to bind water, reduce fat absorption, and control the viscosity. Examples of these gums are guar gum, locust bean gum and carboxymethyl cellulose. 

There have been a number of reports of the use of enzymes in the extraction of oils from sources such as fish, rape seed, yeast, palms, and soya beans. Celluloses and pectinases are used in pdm oil extraction. In soya bean and fish, much oil has been found to be associated with protein, so that addition of proteases increases the yield of oil and protein. Use of thermostable proteases is preferred, but m general the use of enzymes is limited by the minimal water contents of the various process streams. Trichoderma uride and A niger celluloses, hemicellulases and proteases have been used to extract hydrocarbons from Euphorbia plants 39 40) and similar enzymes used to extract sapogenins from Helleborus 41). 

There are three ways to obtain the total solid (1) determine the water content by Karl Fisher titration, (2) weigh an evaporate portion of product, or (3) sum up all the ingredients, including mometasone furoate and phenylethyl alcohol, which are stated (claimed) on the label. The combination of all three measurements generally gives quite an accurate estimation of the total solid and total cellulose ... 

The phase transfer catalyzed alkylation reaction of dodecyl phenyl glycidyl ether (DPGE) with hydroxyethyl cellulose (HEC) was studied as a mechanistic model for the general PTC reaction with cellulose ethers. In this way, the most effective phase transfer catalysts and optimum reaction concentrations could be identified. As a model cellulose ether, CELLOSIZE HEC11 was chosen, and the phase transfer catalysts chosen for evaluation were aqueous solutions of choline hydroxide, tetramethyl-, tetrabutyl-, tetrahexyl-, and benzyltrimethylammonium hydroxides. The molar A/HEC ratio (molar ratio of alkali to HEC) used was 0.50, the diluent to HEC (D/HEC) weight ratio was 7.4, and the reaction diluent was aqueous /-butyl alcohol. Because some of the quaternary ammonium hydroxide charges would be accompanied by large additions of water, the initial water content of the diluent was adjusted so that the final diluent composition would be about 14.4% water in /-butyl alcohol. The results of these experiments are summarized in Table 2. 

Because of the extraordinary supramolecular structure and exceptional product characteristics as high-molecular and high-crystalline cellulosics with a water content up to 99%, nanocelluloses require increasing attention. This review assembles the current knowledge in research, development, and application in the field of nanocelluloses through examples. The topics combine selected results on nanocelluloses from bacteria and wood as well as their use as technical membranes and composites with the first longtime study of cellulosics in the animal body for the development of medical devices such as artificial blood vessels, and the application of bacterial nanocellulose as animal wound dressings and cosmetic tissues. 

The MSC has been shown to work well in several empirical studies [9, 10], which showed an improvement in the performance of multivariate calibrations and a reduction in the number of factors in PCA. For example, NIR reflectance spectra of 20 powder samples of microcrystalline cellulose are shown in Figure 4.8a. Due to differences in particles size from sample to sample, there are significantly different baseline offsets. The same spectra are shown in Figure 4.8b after multiplicative scatter correction. The different baseline offsets observed in Figure 4.8a are so large that they mask important differences in the water content of these samples. These differences are revealed in the water absorption band at 1940 nm after the baseline offsets have been removed by MSC. 

Vanilla contains 25% of sugars, 15% fat, 15-30% cellulose and 6% minerals (Uhl, 2000). Water content is unusually high (35%). The nutritional content of vanilla extract in 34.4% ethanol is given in Table 15.2 (USDA National Nutrient Database for Standard Reference, 2002). 

Fig. 18 a, b. Typical permeabilities of various hydrogels to water and various solutes (a) Water permeability at pressures less than 7 x 107 dyne/cm2 531 (1) = polyelectrolyte complex of poly-(sodium styrenesulfonate) (NaSS)-poly(4-vinylbenzyltrimethylammonium chloride) (PVBMA), (2) = crosslinked hydrogel of poly(2-hydroxyethyl methacrylate), (3) - cellulose (b) Dialytic permeability of a polyelectrolyte complex composed of NaSS-PVBMA to solutes with various molecular weights541 (1) Water, (2) neutral polyelectrolyte complex (water content = 70%), (3) anionic polyelectrolyte complex (water content = 61%), (4) cellophane and cuprophane (water content = 57%)... 

Also the diffusivity of water in polymers is highly dependent on the polymer-water interaction. When a polymer contains many hydrogen-bonding groups (cellulose, poly (vinyl alcohol), proteins, etc., and to a lesser extent synthetic polyamides) the diffusivity increases with the water content. This is explained by the strong localisation of the initially sorbed water over a limited number of sites, whereas at higher water contents the polymer... 

The nitric acid concentration in the nitration acid mixture is usually 20-25%. The degree of nitration can be regulated by changes in the water content. Examples of the solubility and use of cellulose nitrates are given in Table 9-3. As a by-product in the nitration process some cellulose sulfate is also formed (see below). Because this results in instability of the cellulose nitrate, the sulfate groups must be removed by various treatments and the sulfuric acid formed removed by washing. 

Starch can also be modified by fermentation as used in the Rodenburg process. In this case the raw material is a potato waste slurry originating from the food industry. The slurry mainly consists of starch, the rest being proteins, fats and oils, inorganic components and cellulose. The slurry is held in storage silos for about two weeks to allow for stabilisation and partial fermentation. The most important fermentation process that occurs is the conversion of a small fraction of starch to lactic acid by mans of the lactic acid bacteria that are naturally present in the feedstock. The product is subsequently dried to a final water content of 10% and then extruded. 

The carboxymethylation of cellulose with sodium chloroacetate in an aqueous system generally showed that the 2-OH group was more reactive than the 6-OH group, whereas the 3-OH was the least reactive. A low water content medium resulted in a relatively more uniform reactivity than a high water content reaction [202]. Similarly, carboxymethylation in a nonaqueous system (SO2-DEA-DMSO) [79] resulted in a more uniform reaction and a higher reactivity of the 6-OH group as compared to an aqueous reaction. Interestingly, carboxymethylation with sodium iodoacetate substantially enhanced the reactivity of the 3-OH, which was found to be most reactive under this condition. 

In a Soviet study23,24 the mobility of cellulose macromolecular fragments was investigated by means of the paramagnetic label technique. Cellulose macroradicals serving as paramagnetic centres were obtained by irradiation of cellulose at —120° to —140 °C. The mobility of their fragments was found to increase sharply with the water content in the sample to reach a maximum at 10% water. It is this increase which appears to be responsible for the rapid decomposition of macroradicals in moist cellulose. 

Figure 15. Specific rotation dependence at 25 C on the water content and on storage time 25.5/74.5 ( ), 23.0/75.0/2.0 (o), cellulose concentration, 12g/100mL DP, 210.

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