Alternative sweeteners are simply alternatives to sucrose and other mono- and disaccharides that provide sweetness. Many have been developed to provide zero-calorie or low calorie sweetening for foods and drinks.
Because many of these provide little to no calories, these sweeteners are also referred to as non-nutritive sweeteners (FDA is using high-intensity sweeteners to describe these products3). Aside from tagatose, all of the sweeteners on the list below meet this criteria. Aspartame does provide calories, but because it is far sweeter than sugar, the small amount used does not contribute meaningful calories to a person's diet. Until the FDA allowed the use of stevia, this collection of sweeteners were commonly referred to as artificial sweeteners because they were synthetically or artificially produced. However, with stevia, the descriptor artificial can no longer be used to describe these sweeteners. More recently, Luo Han Guo Fruit extracts have also been allowed to be used as another high-intensity sweetener that is not synthesized or artificially produced. The table in the link below summarizes the characteristics of the FDA approved high-intensity sweeteners.
Web Link: FDA High-Intensity Sweeteners
Saccharin is the oldest of the artificial sweeteners. You do not want to use it in cooking or baking because it develops a bitter taste4.
Figure 2.131 Structure of saccharin5
Aspartame is made up of 2 amino acids (phenylalanine and aspartate) and a methyl (CH3) group. The compound is broken down during digestion into the individual amino acids. This is why it provides 4 kcal/g, just like protein4. Because it can be broken down to phenylalanine, products that contain aspartame contain the following message: "Phenylketonurics: Contains phenylalanine." Phenylketonuria (PKU) will be covered in greater detail in section 2.25. When heated, aspartame breaks down and loses its sweet flavor1.
Figure 2.132 Structure of aspartame6
Neotame is like aspartame version 2.0. Neotame is structurally identical to aspartame except that it contains an additional side group (bottom of figure below, which is flipped backwards to make it easier to compare their structures). While this looks like a minor difference, it has profound effects on the properties of neotame. Neotame is much sweeter than aspartame and is heat-stable. It can still be broken down to phenylalanine, but such small amounts are used that it is not a concern for those with PKU1,4.
Figure 2.133 Structure of neotame7
The newest, sweetest alternative sweetener approved by the FDA in 2014 is advantame. It is heat-stable and does not have a trade name yet3. Notice it also has a similar structure to aspartame and neotame. Like Neotame it can broken down to phenylalanine, but such small amounts are used that it is not a concern for those with PKU. However, it has a much higher acceptable daily intake than Neotame4, meaning there is less concern about adverse effects from consuming too much.
Figure 2.134 Structure of advantame8
Acesulfame-potassium (K) is not digested or absorbed, therefore it provides no energy or potassium to the body1. It is a heat-stable alternative sweetener.
Figure 2.135 Structure of acesulfame-potassium (K)9
Sucralose is structurally identical to sucrose except that 3 of the alcohol groups (OH) are replaced by chlorine molecules (Cl). This small change causes sucralose to not be digested and as such is excreted in feces1,4. It is a heat-stable alternative sweetener.
Figure 2.136 Structure of sucralose10
Stevia is derived from a South American shrub, with the leaves being the sweet part. The components responsible for this sweet taste are a group of compounds known as steviol glycosides. The structure of steviol is shown below.
Figure 2.137 Structure of steviol12
The term glycoside means that there are sugar molecules bonded to steviol. The two predominant steviol glycosides are stevioside and rebaudioside A. The structure of these two steviol glycosides are very similar13. The structure of stevioside is shown below as an example.
Figure 2.138 Structure of stevioside14
The common name for a sweetener containing primarily rebaudioside A is rebiana13. Stevia sweeteners had been marketed as a natural alternative sweeteners, something that has been stopped by lawsuits as described in the following link. Stevia is a heat-stable alternative sweetener.
Web Link: What is natural and who decides?
Luo Han Guo Fruit Extracts
Luo Han Guo (aka Siraitia grosvenrii Swingle, monk) fruit extracts are a newer, natural heat-stable alternative sweetener option derived from a native Chinese fruit. These extracts are sweet because of the mogrosides that they contain3. The structure of a mogroside is shown below.
Figure 2.139 Structure of a mogroside15
References & Links
- Whitney E, Rolfes SR. (2008) Understanding nutrition. Belmont, CA: Thomson Wadsworth.
- Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.
- Carakostas MC, Curry LL, Boileau AC, Brusick DJ. (2008) Overview: The history, technical function and safety of rebaudioside A, a naturally occurring steviol glycoside, for use in food and beverages. Food and Chemical Toxicology 46 Suppl 7: S1.
- FDA High-Intensity sweeteners - http://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm397725.htm
- What is natural and who decides? - http://www.nutraingredients-usa.com/Markets/Pure-Via-to-settle-class-action-suit-over-natural-claims