Fructose solution

The fructose solution was decolorized by treatment with activated charcoal and concentrated under vacuum to a thick syrup. Two volumes of hot 95% ethyl alcohol were added, and the solution was heated to a boil and filtered to remove a small amount of insoluble material. After cooling, three volumes of ethyl ether were added, and the solution was allowed to stand overnight in the refrigerator. Fructose separated from the solution as a thick syrup and was... 

The PMBV/PVA hydrogel containing ES cells was dissociated by the addition of 0.2 M D-fructose solution after 3 days. After dissociation of the PMBV/PVA hydrogel, the recovered ES cells were cultured on gelatin-coated TCPS in the culture medium as usual, and the differentiation characters of recovered ES cells were estimated by alkaline phosphatase (ALP) staining (Fig. 14). 

Fig. 1.48. Results of annealing (thermal treatment) on the formation of ice in a 60 % fructose solution (1) and in a 60 % glucose solution (2).

Fig. 1.55.2. Dimension change as a function of temperature for 30 % fructose solution during freezing at 5 °C/min down to -80 °C.

Several products were also detected in base-degraded D-fructose solution acetoin (3-hydroxy-2-butanone 62), l-hydroxy-2-butanone, and 4-hydroxy-2-butanone. Three benzoquinones were found in the product mixture after sucrose had been heated at 110° in 5% NaOH these were 2-methylbenzoquinone, 2,3,5-trimethylbenzoquinone, and 2,5-dimethyl-benzoquinone (2,5-dimethyl-2,5-cyclohexadiene-l,4-dione 61). Compound 62 is of considerable interest, as 62 and butanedione (biacetyl 60) are involved in the formation of 61 and 2,5-dimethyl-l,4-benzenediol (63) by a reduction-oxidation pathway. This mechanism, shown in Scheme 10, will be discussed in a following section, as it has been proposed from results obtained from cellulose. 

No nucleatlon occurs provided the supersaturation is kept below a value equivalent to 35 C of subcooling. There Is a size spread effect, but it decreases with high ethanol contents. The results Indicate that a practical process Is feasible to grow large fructose crystals by the addition of ethanol to aqueous fructose solutions. 

Properties of EthanolIc Fructose Solutions. Published information on the properties of aqueous ethanolic fructose solution is very limited. As a result, solubility data from 25 to 60 °C was measured (Figure 1) and will be published separately. The equilibrium fructose/water mass ratio for zero alcohol, ranges from over 4 at 25 C to over 8 at 60 C (7,8). It can be seen that reasonable yields will only result with high alcohol additions (E/W at least 2). This is the range used in this study. Aqueous ethanolic solutions have a wide range of viscosities. These were measured at operating conditions using a Rheomat concentric cylinder viscometer. 

Limiting Supersaturation for Nucleation. Like sucrose, D-fructose solutions can tolerate a high degree of supersaturation without nucleating, even in the presence of seed crystals. This is the metastable region on the Miers supersolubility diagram (9). 

Figure 2. Limiting subcooling before aqueous fructose solutions nucleate.

Stock fructose solution, 1000 pg mh of fructose - dissolve 1.0000 g fructose in saturated benzoic acid solution and make up to 1 I in a volumetric flask and mix. 

To accommodate these facts, the earliest mechanisms proposed for degradation of D-fructose assumed that it was present in the furanose form, and that the ring remained intact. It was assumed that the initial reaction was the elimination of water, to form the 1,2-enolic form of 2,5-anhydro-D-mannose, and that further dehydration resulted in 2-furaldehyde. The necessity for D-glucose to isomerize to D-fructose was assumed to account for the much lower reaction-rate of D-glucose. This mechanism does not account for the observation that 2,5-anhydro-D-mannose is less reactive than D-fructose, nor is there any evidence that 2,5-anhydro-D-mannose is present in reacting D-fructose solutions. Nevertheless, similar mechanisms have since been proposed.13-16 Because of the ease of mutarotation of D-fructose... 

Fructose is unique among known sugars in being sweeter than sucrose. In solution, fructose can exist as four or five isomers, and the relative sweetness of a solution is dependent upon the equilibrium between the sweeter pyranose isomers and the less sweet furanose isomers, which is in turn dependent on such conditions as pH and temperature. In cold conditions the pyranose form predominates and, therefore, fructose solutions are sweeter (Danisco Sweeteners, 2003). Fructose has a clean, sweet taste it is also synergistic with many bulk and intense sweeteners and is often used at low levels to improve the taste profile of some intense sweeteners. It is very soluble and also relatively hygroscopic, compared with sucrose (Danisco Sweeteners, 2003). 

The fructose solution was decolorized by treatment with activated charcoal and concentrated under vacuum to a thick syrup. Two volumes of hot 95% ethyl alcohol were added, and the solution was heated to a boil and filtered to... 

Answer Straight-chain fructose can cyclize to yield either the pyranose or the furanose structure. Increasing the temperature shifts the equilibrium in the direction of the furanose form, reducing the sweetness of the solution. The higher the temperature, the less sweet is the fructose solution. 

The drugs were administered for 11 days. Two hours after treatment on the 10 th day blood samples were taken retroorbitally100 and analyzed for total cholesterol 101 Then the animals received 10% fructose solution in place of drinking water for the next 24 h. After the last administration of the test compound or mixture the rats were killed, blood samples were taken, and the serum obtained was analyzed for triglycerides102. ... 

Youn, K.-S. and Rao, M. A. 2003. Rheology and relationship among rheological parameters of cross-linked waxy maize starch dispersions heated in fructose solutions. J. FocxlSci. 68 187-194. 

Collins J. Metabolic disease. Time for fructose solutions to go. Lancet 1993 341(8845) 600. 

Evidence has also been educed for the formation of two constituents, re-ductone and l,3-dihydroxy-2-propanone, by symmetrical scission of the D-fructose molecule these constituents are mainly responsible for the peak at 285-290 m/u in the ultraviolet absorption spectrum of the D-fructose solutions. 

There is evidence for the presence of slow post-irradiation processes when sugar solutions are irradiated in oxygen and under vacuum. When n-glu-cose solutions are irradiated under vacuum, the absorption at 265 m/ increases steadily and attains a maximum at 20-30 hr. after irradiation has ceased. " Similarly, for D-fructose solutions irradiated in oxygen and under vacuum, the absorption maxima continue to increase for several days after irradiation has ceased. This process may be associated with the postirradiation decrease in concentration of hydrogen peroxide at a rate of 3-4 X 10 molecules min. ml. in irradiated n-fructose " and o-glucose " solutions. The occurrence of post-irradiation reactions is further demonstrated in these systems by a liberation of g9.s for 24-30 hr. after irradiation is terminated. " Further detailed examination of these interesting reactions is necessary, before it will be possible to speculate about their association with several important post-irradiation processes encountered when biological systems are irradiated. ... 

Table II Physical properties of aqueous fructose solutions at 20°C.

If a 20% fructose solution is selected. Young [17] shows in diagram (Fig. 2.63), that pure ice freezes out from this mixture at appr. -2.5°C this is a result of the known phenomenon of freezing point reduction in solutions. The freezing-out of pure ice, however, causes an increase in the sugar concentration and thus a further freezing point depression. This continues until a mixture of ice and fmctose dihydrate is present at -10°C. This lowest common solidification point is called eutectic point . 

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