Non-nutritive sweeteners are used to sweeten food products without adding calories. Learn how aspartame, sucralose, acesulfame K, saccharin, and neotame compare.
Non-nutritive sweeteners, artificial sweeteners, or sugar substitutes are used to sweeten foods and beverages without significant calories. Unlike natural sugars like sucrose and fructose, non-nutritive sweeteners are typically many times sweeter per unit of weight. They are often used in very small amounts to achieve the desired level of sweetness. They are commonly used by those who want to reduce their calorie intake, manage blood sugar levels, or avoid consuming too much sugar. This article will explore five common non-nutritive sweeteners: aspartame, sucralose, acesulfame K, saccharin, and neotame.
About Non-Nutritive Sweeteners
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Aspartame is the methyl ester of the aspartic acid / phenylalanine dipeptide.
Sucralose is the halogenated derivative of sucrose.
Acesulfame K belongs to the class of dihydro-oxathiazinone dioxides.
Saccharin belongs to the N-sulfonyl amide structural class.
Neotame is a derivative of aspartame.
Chemical Synthesis & Production
Aspartame
Synthesized by combining the amino acids L-phenylalanine and L-aspartic acid by methyl-ester linkage. The amino acids are then coupled either chemically or enzymatically, followed by a series of crystallization steps to remove impurities. The technique employed influences the type, size, shape, and other properties of the crystal formed, affecting the performance of the sweetener.
Sucralose
Synthesized by the selective replacement of three hydroxyl groups on the sucrose molecule by three chlorine atoms. The process includes selective protection of the essential hydroxyl groups, followed by chlorination, deblocking, and purification.
Acesulfame K
Synthesized by the oxidation of o-methyl-benzenesulfonamide is obtained by the chlorosulfonation of toluene with chlorosulfonic acid. Alternatively, diazotization of methyl anthranilate and treatment with sulfur dioxide, chlorine, and finally ammonia leads directly to saccharin.
Saccharin
Synthesized by the oxidation of o-methyl-benzenesulfonamide is obtained by the chlorosulfonation of toluene with chlorosulfonic acid. Alternatively, diazotization of methyl anthranilate and treatment with sulfur dioxide, chlorine, and finally ammonia leads directly to saccharin.
Neotame
Synthesized using aspartame and 3,3-dimethylbutyraldehyde react via reduction alkylation followed by purification, drying, and milling.
Typical Properties
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Solubility
Should be stored in an airtight container in a cool, dry place
28.2 g/100 mL at 20◦C
∼270 g/L at 20°C
1200g/ L in water at ambient temperature — solubility increases with temperature. Both sodium and calcium salts readily dissolve in water.
1.3% at 25°C — increases with rising temperature.
Molecular Weight
294.30 g/mol
397.6 g/mol
201.24 g/mol
183.18 g/mol
378.5 g/mol
Melting Point
246-247°C
130°C
250°C
228°C
81-84°C
pH
5.3 (0.8% aqueous solution)
5-6 (10% aqueous solution)
–
2.0 (0.35% w/v aqueous solution)
5.8 (0.5% w/w aqueous solution)
pKa
pKa1 = 2.96 (carboxyl); pKa2 = 7.30 (amine)
–
–
1.6
pKa1 = 3.66pKa2 = 9.22
Density
1.347 g/cm3
1.69 g/cm3
1.04 g/cm3
0.7–1.0 g/cm3
1.1±0.1 g/cm3
Storage Conditions
Should be stored in an airtight container in a cool, dry place
Should be stored in an airtight container in a cool, dry place
Should be stored in an airtight container in a cool, dry place.
Should be stored in an airtight container in a cool, dry place.
Should be stored in an airtight container, in a cool, dry place.
Typical Applications
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Compatibility
Aspartame is suitable for use in products that do not require high temperature and pH treatments. Ideal for use with low-moisture foods. Incompatible for foods with prolonged high-temperature heat treatment.
Acesulfame K is suitable for use in food products requiring high-temperature treatments for prolonged periods.
Neotame is suitable for use in products that do not require high temperature and pH treatments. Ideal for use in low-moisture foods.
Saccharin is suitable for use in foods with high-temperature treatment requirements. Not suitable for highly acidic foods.
Neotame is suitable for use in products that do not require high temperature and pH treatments. Ideal for use in low moisture foods.
The maximum sweetness possible for saccharin is equivalent to that of 10.1% sucrose. It isn’t easy to formulate food using saccharin only as a sweetener.
Sucralose works well when used as a solo sweetener in food products.
Has a clean, sweet taste similar to sucrose. Maximum sweetness intensity occurs at 15.1% SE and can be used as the sole sweetener in some applications. Neotame is also reported to mask off-tastes, even at sub-threshold use levels, associated with soy, vitamin and mineral fortification.
Unlike many other intense sweeteners, aspartame’s taste profile is good enough to stand alone. Its maximum sweetness intensity is 13-14% sucrose equivalence (SE), within the range of use as a sole sweetener in most applications. Its sweetness profile is much more similar to sucrose than any non-nutritive sweetener.
Has a clean, sweet taste similar to sucrose. Maximum sweetness intensity occurs at 15.1% SE and can be used as the sole sweetener in some applications. Neotame is also reported to mask off-tastes, even at sub-threshold use levels, associated with soy, vitamin, and mineral fortification.
Synergistic Usage
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Frequently blended with acesulfame K or saccharin. Used to modify the taste of acesulfame K, and saccharin. Aspartame also has some flavor-enhancing properties, especially in the case of fruit flavors.
Frequently blended with acesulfame K or saccharin. Used to modify the taste of acesulfame K and saccharin. Aspartame also has some flavor-enhancing properties, especially in the case of fruit flavors.
Acesulfame K enhances aspartame, sodium cyclamate, and sucralose. Brings the sweetness profile of aspartame, cyclamate, and sucralose closer to sucrose.Combines well with sugar alcohols.
Saccharin enhances aspartame and cyclamate. It enhances sweetness when combined with sugar alcohol. Sativoside and rebaudiosides work in synergy with saccharin.
Saccharin enhances aspartame and cyclamate. It enhances sweetness when combined with sugar alcohols. Sativoside and rebaudiosides work in synergy with saccharin.
Formulation Considerations
Sensory Properties
Non-caloric sweeteners differ in taste from carbohydrate sweeteners in several ways. Generally, they are more potent, enabling them to be used at significantly lower concentrations. In addition, many of them exhibit “off-tastes” such as bitter, metallic, cooling, or licorice-like. Finally, nearly all of them exhibit sweetness that is slower in onset, which lingers relative to carbohydrate sweeteners.
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Color
White
White
White
White
White
Odor
Odorless
Odorless
Odorless
Odorless
Odorless
Taste
Unique sugar-like taste
Pleasant sugar-like taste
Sweet taste
Sweet taste
The sucralose potency decreased slightly from the lowest to the highest sucrose concentration. Potency depends on factors such as the sweetness level, pH, temperature, and the presence of other ingredients.
Taste Characteristics
Onset time is slightly longer than sucrose, but it has a lingering tail.
Sucralose’s sweetness has a slightly longer duration than sucrose.
The sweetness of acesulfame K is perceived quickly and without any unpleasant delay. No lingering taste.
The onset and duration are somewhat similar to that of sucrose.
Neotame has a slightly slower onset time than aspartame and sucrose. It has a slightly lingering sweetness.
Off taste
No off-taste
No metallic notes
Perceivable at elevated levels
Metallic taste
No bitter or metallic taste
Aftertaste
No bitter aftertaste
No bitter aftertaste
Lingering bitter aftertaste
Bitter aftertaste
No aftertaste
Relative sweetness
Relative sweetness (RS) of aspartame varies with concentration, as with all intense sweeteners. At threshold sweetness (0.34%) in water, RS is 400 (where sucrose = 1), while at 10% SE, it falls to 130.
The bitterness is more pronounced at higher concentrations, flattening the sweetness function.
Relative sweetness (RS) of aspartame varies with concentration and all intense sweeteners. At threshold sweetness (0.34%) in water, RS is 400 (where sucrose = 1), while at 10% SE, it falls to 130.
The maximum sweetness possible for saccharin is equivalent to that of 10.1% sucrose.
The maximum sweetness intensity occurs at 15.1% SE, making neotame usable as a sole sweetener in some applications.
Temperature and pH Stability
A non-caloric sweetener must be stable to degradation from hydrolytic, pyrolytic, or photochemical processes encountered in food or beverage applications. Stability is critical for the following reasons:
The degradation rate must not be such that product shelf life is affected.
Degradation must not cause any off-taste or odor.
Any degradation products formed must also be safe.
Aspartame
Stable in dry form in elevated temperatures (<8% moisture level). Less stable in liquid systems. Maximum rate of conversion to degradation products is seen in a temperature range of 140-160°C.Degradation advances during prolonged heat treatment. It can be minimized using a high-temperature therapy for a short time (HTST) followed by rapid cooling. It is most stable in the range of pH 3-5. Stability decreases with increasing temperature and changes in pH.
Sucralose
Stable in dry form in elevated temperatures. Less stable in liquid systems. The hydrolysis of neotame to de-esterified neotame occurs slowly and depends on pH and temperature. The optimum pH for maximum stability is 4.5. Neotame takes a bell-shaped curve for pH stability.
Acesulfame K
Saccharin is mostly stable up to 150°C when the pH is maintained to neutral or near neutral. The degradation pathway is pH-dependent.At acidic pH, the exclusive hydrolysis product is 2-sulfobenzoic acid, while under alkaline conditions, the sole degradation product is 2-sulfonamidobenzoic acid.
Saccharin
Saccharin is mostly stable up to 150°C when the pH is maintained to neutral or near neutral. Degradation pathway is pH-dependent.At acidic pH, the exclusive hydrolysis product is 2-sulfobenzoic acid, while under alkaline conditions, the sole degradation product is 2-sulfonamidobenzoic acid.
Neotame
Stable in dry form in elevated temperatures. Less stable in liquid systems. The hydrolysis of neotame to de-esterified neotame occurs slowly and depends on pH and temperature. The optimum pH for maximum stability is 4.5. Neotame takes a bell-shaped curve for pH stability.
Metabolism, Absorption, Excretion
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Metabolism
The body does not metabolize sucralose.
The body does not metabolize AceK.
Humans do not metabolize Saccharin.
Neotame is broken down into de-esterified neotame methanol. The methanol produced is very small in quantity.
Neotame is absorbed rapidly (0.5 hours) and rapidly eliminated with a half-life (t1/2) ranging from 0.61 hours to 0.75 hours.
Absorption
The kidneys excrete AceK.
Aspartic acid and phenylalanine are absorbed in the intestinal lumen, essential in nitrogen and energy metabolism.
AceK is not absorbed.
~95% of the dosage is absorbed into circulation.
Neotame is absorbed rapidly (0.5 hours) and rapidly eliminated with a half-life (t1/2) ranging from 0.61 to 0.75 hours.
Excretion
The small amount of methanol produced is excreted from the body via urine.
∼85% of ingested sucralose is eliminated in the feces largely unchanged, while ∼15% of the dose is absorbed and eliminated through urine.
Neotame is absorbed rapidly (0.5 hours) and rapidly eliminated with a half-life (t1/2) ranging from 0.61 to 0.75 hours.
In humans, oral doses are excreted almost completely by the kidneys, with the balance in the feces.
Absorbed neotame and de-esterified neotame are excreted in the urine and feces.
Effects on Health
Aspartame
Sucralose
Acesulfame K
Saccharin
Neotame
Oral Health
Not cariogenic
Not cariogenic
Not cariogenic
Not cariogenic
It does not spike blood sugar levels, making it ideal for managing diabetes.
Weight Management
It does not spike blood sugar levels, making it suitable for managing diabetes.
It does not spike blood sugar levels, making it ideal for managing diabetes.
It helps manage weight as fewer calories contribute to the desired sweetness than sucrose.
It does not contribute calories, making it helpful in managing weight.
It does not contribute calories, making it useful for managing weight.
Diabetes Management
It does not spike blood sugar levels, making it ideal for managing diabetes.
It does not spike blood sugar levels, making it ideal for managing diabetes.
It does not spike blood sugar levels, making it ideal for managing diabetes.
It does not spike blood sugar levels, making it suitable for managing diabetes.
It helps in managing weight as fewer calories contribute to the desired sweetness than sucrose.
Low-calorie plant-based sweeteners are excellent alternatives to sugar. Compare stevia, monk fruit extract, and thaumatin, three of the most popular sweeteners.
