Fructose relative sweetness

The high sweetness of fructose combined with that of glucose means invert sugar is sweeter than sucrose, so it provides a cheaper, less calorific sweetener than sucrose. The relative sweetness figures for sucrose, glucose and fructose are 1.0, 0.7 and 1.7 respectively. Honey is also composed mainly of invert sugar. 

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). 

Sweetness is an important and easily identifiable characteristic of glucose- and fructose-containing sweeteners. The sensation of sweetness has been extensively studied.80-82 Shallenberger83 defines sweetness as a primary taste. He furthermore asserts that no two substances can have the same taste. Thus, when compared to sucrose, no other sweetener will have the unique properties of sweetness onset, duration and intensity of sucrose. It is possible to compare the relative sweetness values of various sweeteners, as shown in Table 21.17,84 but it must be kept in mind that these are relative values. There will be variations in onset, which is a function of the chirality of the sweetener,85 variations in duration, which is a function of the molecular weight profile and is impacted by the viscosity, and changes in intensity, which is affected by... 

Table IV Relative sweetness of fructose and other sugars.

Most tests have shown D-fructose to be the sweetest of the sugars, although the actual ratios between the various sugars depend to a considerable extent on the taster and on the methods and conditions adopted for the comparison. Compared to a sweetness value for sucrose of 100, that for D-fructose has been reported as varying from 103 to 173. The alleged relative sweetnesses of some sugars and other organic compounds can be found in Ref. 1. 

Cameron reported that in 10% solution of sucrose as a basis of comparison, dextrose had a relative sweetness of 68.5% and fructose or levulose was 20.5% sweeter than sucrose (1). The most widely accepted sweetness for anhydrous dextrose is 70 to 75% that of sucrose. Calculating resultant sweetness of a 10% sucrose solution converted to invert sugar based on equivalent dextrose sweetness, we get from Cameron s figures ... 

Raman and i.r. spectra of crystalline D-fructose, L-sorbose, 5-deoxy-D-threo-hexulose (1.e., 5-deoxy-D-fructose), and D-arablnose In the 3100-3650, 2800-3000, and 200-1600 cm regions and the Raman spectra in the 10-200 cm region have been reported. Bands due to OH stretching were correlated with 0H.H distances and results discussed In relationship to relative sweetness. The hydrogen-bond system In crystalline a-D-glucopyranose has been... 

The relative sweetness of a number of sugars and artificial sweeteners is given in Table 23.3. Somewhat lower thresholds than those given in Table 23.2 were obtained for sucrose (0 017 %), fructose (0 016 %), glucose (0-132 %), and lactose (0-0160%) when expressed as the concentration at which 50% of the responses correctly distinguished the sugar solution from a distilled water blank [23]. 

The taste sense and the relative sweetness of sugars and other sweet substances have been critically reviewed (77). At certain concentrations mixtures of isosweet solutions of sucrose and corn sirup are slightly sweeter than either parent solution. a-D-Glucose is somewhat sweeter than jS-D-glucose. Therefore, fresh a-D-glucose solutions are sweeter than those in which there is an equilibrium between the a- and j3-forms. Because fructose is almost twice as sweet as glucose, it would seem that inversion of sucrose ought to increase its sweetness. This occurs, but it is not noticeable at concentrations below 10%. 

By use of the semi-empirical molecular orbital method AMI, the optimised geometries and energies of the pyranoid forms of D-fructose (14), L-sorbose (15), 5-deoxy-D-rhreo-hexulose (16), and carba-D-fmctose (17) have been determined. The findings that a low-energy conformation exists for each of the three sweet compounds (14), (16), and (17) [but not for the non-sweet analogue (15)] in which HO-2 is hydrogen-bonded to 0-3, is thought to provide an explanation for the relative sweetness of these compounds. ... 

Table 10.16. Relative sweetness of saccharose, glucose, fructose and lactose ...

Acid or enzymatic hydrolysis of sucrose, inversion, produces an equimolar mixture of n-glucose and n-fructose known as invert sugar. Invert sugar is used as a food additive substance, usually in the form of syrup (relative sweetness is 95-105% of saccharose sweetness). It also serves as a starting material for obtaining d-glucose and D-fructose, the sweeteners mannitol and glucitol and other substances. 

The role of fructose as a food and in the food processing industry in the United States is not yet clear. Although its desirable physical and chemical characteristics are well documented, its basic attractiveness appears to be related to its relative sweetness when compared with sucrose. In theory, substitution of fructose for sucrose in foods (especially soft drinks) would permit a reduction in the caloric content of a food because of the greater relative sweetening power of fructose. 

The most commonly used sweeteners are sucrose, glucose, fructose, sorbitol, and glycerin. Using sucrose (sugar) as a standard, with 100 units of sweetness. Table 6 lists the relative intensities of other sweeteners. Sweetness intensity changes with concentration. It has been estimated that the sweetness of glucose relative to cane sugar is 53 at a concentration of 8% but... 

In recent years, crystalline D-fructose has been produced and offered not only as an unusually sweet sugar but as a beneficial sweetening agent for people with certain ailments or, because of its claimed ease of metabolism, for athletes in whom it is said to provide quick energy. A review of the voluminous literature on the metabolism of D-fructose presents relatively clear information, and an attempt is made in this article to set forth a useful summary. 

Sucrose is produced in a high state of purity on an enormous scale—more than 80 million tons per year. About 40% of the world s sucrose production comes from sugar beets and 60% comes from sugarcane. A comparison of the sweetness of common sugars and artificial sweeteners relative to sucrose is given in Table 15.1. Honey, which is a mixture of the monosaccharides glucose and fructose, has been used for centuries as a natural sweetener for foods and is sweeter than sucrose, or cane sugar (Table 15.1). To convert cane... 

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