Sugar and Sugar substitutes

Artificial Sweetners

For a nice overview of artificial sweeteners, see the Wikipedia site. The following table shows the relative sweetness of sugar and several artificial sweetners.

	Relative sweetness	Date of Discovery	Synonyms/Products
Sucrose	1	? (Natural)	Table sugar
Glucose	0.6-0.7	? (Natural)	Blood sugar
Fructose	1.4	? (Natural)	Fruit sugar
Sorbitol	0.6	? (Natural)	Sugar alcohol
Saccharin	300	1879	Sweet'N Low
Aspartame	180	1965	Nutrasweet, Equal
Sucralose	500-600	1976	Splenda

Polarity of atoms

Being able to classify bonds (and by extension, molecules) as polar or non-polar is important in order to predict how molecules will interact. Polar molecules are strongly attracted to other polar molecules, but polar molecules and non-polar molecules (like oil and water) tend to not mix. Based on the rules given below, sucrose is known to be very polar. This is consistent with the observation that it is very soluble in water. Artificial sweeteners are also expected to be polar. If they weren't, then they would probably not interact with the sweet receptors in our bodies like sugar does, and we would not recognize them as "sweet".

To determine to polarity of a chemical bond, relative ability of each atom to attract electrons (the atom's electronegativity) must be compared. While this is most commonly done by comparing electronegativy values, a simpler approach that works for most molecules is to look at each atom's position on the periodic table (a portion of which is shown below). Atoms that share an edge have similar electronegativity values, and bonds between these atoms are non-polar. Most other bonds are polar.

	H
B	C	N	O	F
-	Si	P	S	Cl

Common Polar Bonds		Common Non-polar Bonds
O-H		C-C
N-H		C-H
C-O
C-Cl

The structures of several common sweetners are shown below.

Sucrose	Sucralose
3 O-H groups replaced by Cl (1 Chlorine in different geometry than O-H it replaced).
Aspartame	Saccharin
Glucose	Sorbitol
Sorbitol obtained from reduction of glucose. However, it is only slowly digested in the body. Large amounts of sorbitol can cause health problems.