Sucrose crystalline

The marked advances made in the study of bacterial polysaccharides serve only to emphasize the vast amount of work still to be carried out in this field. The recent remarkable achievements in enzymic chemical synthesis (starch, crystalline sucrose, etc.) indicate the growing necessity for greater cooperation11 between enzymologist and chemist in the solution of many biological phenomena. 

Putnam and Boerio-Gates [19] have measured the heat capacity of pure, crystalline sucrose from 4.99 K to above 298.15 K. Their smoothed results up to 298.15 K are shown in Table 11.7. Use the Debye equation and numerical integration of the experimental data to calculate at 298.15 K. 

The density of sucrose is 1.5879 g/cm . The linear expansion coefficient ranges from 0.0028 to 0.0050 percent, depending on the axis. Characteristic infrared (IR) absorption bands occur at 1010, 990, 940, 920, 870, 850 cm (sharp), and at 680, 580 cm" (broad). The specific heat of crystalline sucrose is 415.98 J/mol at 20°C. The dipole moment is 2.8 x 10" cm (8.3D). Sucrose is readily soluble in water and the solubility increases with the rise in temperature. It is sparingly soluble in alcohol but moderately soluble in organic solvents, such as dimethyl formamide, p5nidine, and dimethyl sulfoxide. 

Granulated. Granulated sugar is pure crystalline sucrose. It can be classified into seven types of sugar based on the crystal size. Most of these... 

While the amorphous and crystalline solid forms of sucrose can be readily distinguished by XRD (Fig. 2A), the technique is also capable of revealing the presence of small amounts of crystalline sucrose in the presence of amorphous sucrose. This is evident from the XRD patterns of physical mixtures of amorphous and crystalline sucrose wherein the crystalline sucrose content ranged between 1 and 5wt% (Fig. 2B). 

The limits of detection and quantitation of crystalline sucrose were determined to be 0.9 and 1.8 wt% respectively. Water sorption and FT-Raman spectroscopy also appear to be very sensitive with detection possible down to levels of 1 wt%. ... 

Fig. 9 Plot of the sum of the intensities of the 12.7 and 13.1 20 peaks as a function of the weight percent of crystalline sucrose in mixtures of amorphous and crystalline sucrose. (From Ref. l)...

Flowability crystalline sucrose is free flowing, whereas powdered sucrose is a cohesive solid. 

Sugar spheres are prepared from crystalline sucrose, which is coated using sugar syrup and a starch dusting powder. 

Pregelatinized waxy maize starch (PregePlow CH 20 adipic acid-reticulated, acetic anhydre-stabilized and drum drying-gelatinized) was supplied by Roquette Freres (Lestrem, France) and crystalline sucrose by Merck. 

In many foods, the situation is more complicated. Often, the material, or an important component, may occur either in crystalline or in amorphous form. Figure 8.6a gives examples for sucrose crystalline, amorphous, and in solution. Crystalline sucrose, if pure, cannot contain water and any water present is adsorbed on the crystal faces, and this is a very small amount. Amorphous sucrose can take up water, because this means in fact dilution of an extremely concentrated solution. If sufficient water has been taken up, the diffusion coefficient of sucrose has become large enough for it to crystallize. This then leads to the release of water. The aw and the rate at which these changes occur greatly depend on temperature. 

Grinding crystalline sucrose and adding the aroma compounds will not work most of these compounds are somewhat hydrophobic and will not at all or only slightly adsorb onto sucrose. Even if sufficient aroma can be adsorbed, it soon will be lost by evaporation. 

Sucrose diffusion studies are reported by several authors (U2, 82, 119) and surface tension studies are now in the literature (12, 120). Sherrill recently gave information on the thermal expansion of crystalline sucrose (99). Thermal conductivity (92) and electrical conductivity (32) of sucrose solution recently have been reported. As research in food science continues it is felt these data may be of... 

Sugar beets are harvested in the fields, washed, and cut into small pieces. The beet chips are then soaked in water and pressed to extract the sweet juice in them. The juice is boiled and the liquid evaporated to obtain crystalline sucrose. The solid material remaining from this process can be used as animal feed. 

A weakness, common to all Karl Fischer-type methods, lies in the limitation that they measure the total water content of the sample, irrespective of the water distribution within the sample. In solids that are partially crystalline and partially amorphous, the residual water will be concentrated in the amorphous phase, thus depressing its Tg. This can accelerate or even promote the crystallisation of small molecule substances within the amorphous matrix. Take as an example crystalline sucrose that contains 0.5% of amorphous material and 0.17% of residual water. Since all the water is concentrated in the amorphous phase, the real water content will be 20% with a Tg of 9°C. It is also instructive to calculate the number of water molecule layers for differently sized sucrose particles. This is shown in Table 1. If the measured water content were to rise to 0.5%, corresponding to 50% in the amorphous phase, then Tg of the amorphous phase would be depressed to —70°C. It is therefore useful, if not essential, to have a reasonable estimate of the amorphous content of a preparation. Several more or less laborious methods for its determination hnd application, and they are... 

FIG. 6. Scanning electron micrograph of muscle fiber covered with a layer of crystalline sucrose (arrows). Starch cell fragments labeled C are also shown. Source Chang et aL (1991). Reproduced with kind permission from Elsevier Science Ltd. 

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