Sweet Taste Structural Requirements

B). This also suggests that the AH-B concept represents only a first approximation in the case of peptides. Certainly, the AH-B system is required in the molecule. However, the structural characteristics of the second amino acid sometimes may completely mask any AH-B effect. To test the above hypothesis, we have synthesized a number of peptides with or without a sweet taste. 

The search for new substances that can serve as sweeteners continues. There is a great deal of interest in substances that are naturally occurring and that can be isolated from various plants. In addition, research, including molecular modeling studies and spectroscopic investigations, is attempting to clarify exactly what structural features are required for a sweet taste. Armed with that information, chemists will then be able to synthesize molecules that will be designed specifically for their sweet taste. 

A first requirement for a substance to produce a taste is that it be water soluble. The relationship between the chemical structure of a compound and its taste is more easily established than that between structure and smell. In general, all acid substances are sour. Sodium chloride and other salts are salty, but as constituent atoms get bigger, a bitter taste develops. Potassium bromide is both salty and bitter, and potassium iodide is predominantly bitter. Sweetness is a property of sugars and related compounds but also of lead acetate, beryllium salts, and many other substances such as the artificial sweeteners saccharin and cyclamate. Bitterness is exhibited by alkaloids such as quinine, picric acid, and heavy metal salts. 

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