Sucrose concentrations

Polarization is the most common method for the determination of sugar in sugar-containing commodities as well as many foodstuffs. Polarimetry is apphed in sugar analysis based on the fact that the optical rotation of pure sucrose solutions is a linear function of the sucrose concentration of the solution. Saccharimeters are polarimeters in which the scales have been modified to read directiy in percent sucrose based on the normal sugar solution reading 100%. 

Polarimetric determination of the sucrose concentration of a solution is vaUd when sucrose is the only optically active constituent of the sample. In practice, sugar solutions are almost never pure, but contain other optically active substances, most notably the products of sucrose inversion, fmctose and glucose, and sometimes also the microbial polysaccharide dextran, which is dextrorotatory. Corrections can be made for the presence of impurities, such as invert, moisture, and ash. The advantage of polarization is that it is rapid, easy, and very reproducible, having a precision of 0.001°. 

Density. Measurement of density is widely used in the sugar industry to determine the sugar concentration of symps, Hquors, juices, and molasses. The instmment used is called a hydrometer or a spindle. When it is graduated in sucrose concentration (percent sucrose by weight), it is called a Brix hydrometer or a Brix spindle. Brix is defined as the percent of dry substance by hydrometry, using an instmment or table caUbrated in terms of percent sucrose by weight in water solution. Hydrometers are also graduated in °BaumH, stiU in use in some industries. The relationship between °BaumH and density, ing/cm, is °Baumn Baum e = 145(1 — 1/d). 

The specific rotation ia water is [0 ] ° — +66.529° (26 g pure sucrose made to 100 cm with water). This property is the basis for measurement of sucrose concentration ia aqueous solution by polarimetry. 100°Z iadicates 100% sucrose on soHds. 

Acesulfame-K is a white crystalline powder having a long (six years or more) shelf life. It readily dissolves in water (270 g/L at 20°C). Like saccharin, acesulfame-K is stable to heat over a wide range of pH. At higher concentrations, there is a detectable bitter and metallic off-taste similar to saccharin. Use of the sodium salt of feruHc acid [437-98-4] (FEMA no. 3812) to reduce the bitter aftertaste of acesulfame-K has been described (64). The sweetness potency of acesulfame-K (100 to 200x, depending on the matching sucrose concentration) (63) is considered to be about half that of saccharin, which is about the same as that of aspartame. 

Density gradients to stabilize flow have been employed by Philpot IT> Yin.s. Faraday Soc., 36, 38 (1940)] and Mel [ j. Phys. Chem., 31,559 (1959)]. Mel s Staflo apparatus [J. Phys. Chem., 31, 559 (1959)] has liquid flow in the horizontal direction, with layers of increasing density downward produced by sucrose concentrations increasing to 7.5 percent. The solute mixture to be separated is introduced in one such layer. Operation at low electrolyte concentrations, low voltage gradients, and low flow rates presents no cooling problem. 

A 5 ml sample is adequate to analyse optical density, glucose/sucrose concentration and ethanol concentration. For sugar analysis you may dilute 1 ml of sample and 9 ml of distilled water to have a suitable concentration range for DNS analysis. 

Thus, the increase in concentration needed to match the effect of a 10-fold increase in sucrose concentration is 0.154/2.44 x 10 = 630-fold. Crosby and coworkers suggested that this is close to the situation that occurs with saccharin, and it is doubtless responsible for the differences in perceived sweetness intensity (200-700 times that of sucrose) for sensory determinations conducted at different concentrations. 

The gel/sol transitions cannot be distinguished for pectins extracted by after acid treatment and water-soluble pectins after extrusion. A minimal pectin concentration of 0.2% is required for gelation and no gels can be obtained below a sucrose concentration of 45 %. Commercial pectin (Hercules) with a dm 73 % has a lower phase transition line with a minimal pectin concentration of 0.1 % and sucrose concentration of 40 %. 

Whatever the concentration, commercial pectins formed the strongest gels followed by the acid-extracted pectins and the pectins from the extruded fibres. More differences have be seen when the storage moduli were measured as a function of the sucrose concentration (Figure 7). 

Figure 7 Evolution of the storage moduli of the gels (pH 3, 20°C, 0.6% pectin) with the sucrose concentration.

It is therefore possible to obtain gels with the pectins in the same conditions as other HM pectins. When these pectins are compared to the commercial pectins, it can be observed that higher pectin concentrations were needed and that the gelation was more dependent on the sucrose concentration this fact can be ascribed to a higher purity of the commercial pectins (17,18). 

It was very simply composed by two perpendicular straight lines. No gels can be obtained for fibre concentration lower than 0.5 % and sucrose concentration lower than 50 %. 

FIGURE 5. Effects of varying sucrose concentration on [ H]MDA and [ HJwater incorporation into rat brain synaptosomes... 

A wider problem exists with the possible role of liquid medications in dental caries formation [63], The extent of acid production in the oral cavity is closely related to caries formation. In a study of liquid medication, investigators have observed that medications with sucrose concentrations higher than 15% were able to significantly lower pH there was an inverse relation between sucrose content and a decrease in oral cavity pH [64], In a comparison of sorbitol and sucrose-sweetened liquid iron preparations, only sucrose-containing products produced a significant decrease in oral cavity pH [65],... 

Tzannis and Prestrelski [144,145] showed a concentration-dependent protective effect of sucrose and residual moisture on the activity and stability of tryp-sinogen during spray-drying. They found protein protection even at low carbohydrate concentrations, but they observed some destabilization at very high sucrose concentrations. They hypothesized that phase separation occurs at high sucrose concentrations, resulting in... 

In the presence of sucrose alone as the single substrate, initial reaction rates follow Michaelis-Menten kinetics up to 200 mM sucrose concentration, but the enzyme is inhibited by higher concentrations of substrate.30 The inhibitor constant for sucrose is 730 mM. This inhibition can be overcome by the addition of acceptors.31,32 The enzyme activity is significantly enhanced, and stabilized, by the presence of dextran, and by calcium ions. 

Consider a sucrose concentration gradient across a membrane with 50 mM inside the cell and 500 mM outside the cell at 298 K the transfer from outside to inside is ... 

The chances of a water molecule reaching dendritic ice decrease as sucrose concentration increases, and the distance between the points of the ice stars increases. The addition of polymers reinforces this effect. 

Add 30 mL of 15-50% (w/w) gradient solution to the ultracentrifuge tubes of the swinging bucket rotor (max vol 40 mL). Sucrose concentrations increase from the top to the bottom of the tube. 

Assay the sucrose concentration in each fraction in a perfectometer. 2.1.3.6. Comments... 

Sucrose acrylate derivatives, 23 480 Sucrose concentration, polarimetric determination of, 23 473 Sucrose derivatives, 23 480 Sucrose esters, 23 480 Sucrose hydrolysis, 23 462 Sucrose monoesters (SMEs), 23 480, 481 Sucrose polyester, 23 481 Sucrose separation... 

The formation of the biopolymer dextran is a complex process, where the fructose is known to inhibit the polymer chain growth. Consequently, the separation of the fructose from the reaction zone results in a higher molecular mass of the dextran even at high initial sucrose concentration [173]. In a first investigation, a fixed-bed chromatographic reactor was filled with calcium charged polystyrene. Fructose was retarded on this matrix while the dextran was prevented... 

Starting with a sucrose concentration AO = 1.0 millimol/liter and an enzyme concentration Ceo = 0.01 millimol/liter, the following kinetic data are obtained in a batch reactor (concentrations calculated from optical rotation measurements) ... 

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