Sucrose sweetness-structure relationship

The relationship between structure and enhancement of sweetness in chlorodeoxysucroses was studied by Hough and Khan. Examination of a range of mono-, di-, tri-, and tetra-chlorodeoxy derivatives of sucrose and galacto-sucTOse suggested that C-4, C-1, and C-6 appear to be important in the enhancement of sweetness when substituted with chloro substituents. The increase in sweetness is substantial if a combination of two of these hydroxyl groups is replaced for example, the 4,l -dichloride (55) and the r,6 -dichloride (56) were reported to be respectively 120 and 76 times... 

A structure-sweetness relationship study has shown that the monoglucuronide of glycyrrhetic acid is about 5-times sweeter than 67 and ca. 1000-times sweeter than sucrose [120]. Replacement of the second glucuronic acid by, e. g., xylose or glucose resulted also in an improvement of the taste and enhancement of sweetness [120]. 

As a general rule, sweeteners are rather hydrophilic and bitter molecules have a predominantly hydrophobic character. Because of the close relationships of sweet and bitter tastes (Shallenberger and Acree, 1971) and the already demonstrated (Mathlouthi et al., 1973) role of water in sweet taste chemo-reception, it was decided to record the FT-IR spectra of caffeine, sucrose, and their mixtures in water and to analyze these spectra with the aim of interpreting the taste modalities of these molecules and the inhibition of caffeine bitterness by sucrose on a structural basis. 

The word alcohol immediately brings to mind ethanol, the intoxicating compound in wine and beer. But ethanol is just one member of a family of organic compounds called alcohols that abound in nature. Naturally occurring alcohols include 2-phenylethanol, the compound responsible for the intoxicating smell of a rose cholesterol, a tasty alcohol with which many of us have developed a love-hate relationship sucrose, a sugar we use to satisfy our sweet tooth and many others. In this chapter, we will discuss the structural and physical properties as well as the main chemical reactions of alcohols and their structural relatives, phenols and thiols. 

For a molecule to taste sweet, it must fit into a taste bud site where a nerve impulse can carry the message of sweetness from the tongue to the brain. Not all natural sugars, however, trigger an equivalent neural response. Some sugars, such as glucose, have a relatively bland taste, and others, such as fructose, taste very sweet. Fructose, in fact, has a sweeter taste than common table sugar or sucrose. Furthermore, individuals vary in their ability to perceive sweet substances. The relationship between perceived sweetness and molecular structure is very complicated, and, to date, it is rather poorly understood. 

In a workshop report, the evolution of the structural representation of sucrose from die establishment of its constitutional formula and conformational features to the present-day possibilities for interactive graphic di lay of its molecular geometry and for the computation of contact surface properties relevant for structure-sweetness relationship considerations has been presented. ... 

Sweeteners are natural or synthetic compounds which imprint a sweet sensation and possess no or negligible nutritional value ( nonnutritive sweeteners ) in relation to the extent of sweetness. There is considerable interest in new sweeteners. The rise in obesity in industrialized countries has established a trend for calorie-reduced nutrition. Also, there is an increased discussion about the safety of saccharin and cyclamate, the two sweeteners which were predominant for a long time. The search for new sweeteners is complicated by the fact that the relationship between chemical structure and sweetness perception is not yet satisfactorily resolved. In addition, the safety of suitable compounds has to be certain. Some other criteria must also be met, for example, the compound must be adequately soluble and stable over a wide pH and temperature range, have a clean sweet taste without side or post-flavor effects, and provide a sweetening effect as cost-effectively as does sucrose. At present, some new sweeteners are on the market (e. g., acesulfame and aspartame). The application of a number of other compounds will be discussed here. 

---