Differences between sucrose and sucralose

Sucrose and sucralose are two very common examples of sweeteners, that is, chemicals that we add to foods and drinks with the intention of making them sweeter. While sucrose represents one of the carbohydrates best known to man and is also one of those responsible for the obesity epidemic that plagues countries like the United States, sucralose emerges as an ideal non-calorie alternative for those who wish to reduce as much as possible your sugar intake while still enjoying the sweet taste of your favorite desserts.

In this article we will discuss the differences and similarities between sucrose and sucralose, as well as the main characteristics of each one.

What is sucrose?

Sucrose, also called table sugar, corresponds to one of the most used natural sweeteners around the world. It is a disaccharide, that is, a carbohydrate formed by the union of two individual sugar molecules, namely glucose and fructose. The following figure shows the chemical structure of sucrose, a compound that has a molecular formula of C ₁₂ H ₂₂ O ₁₁ .

Sucrose is mainly produced through the evaporation and crystallization of sugar cane and sugar beet juice. Table sugar, along with another more powerful natural sweetener called high fructose corn syrup, are the most widely used sweeteners in all types of culinary preparations, especially desserts.

From soft drinks to restaurant desserts, many foods and drinks are loaded with sugar. This has contributed to the obesity of millions of people around the world, as well as the development of diabetes in many others. This has prompted the search for substitute sweeteners that provide the same typical sweet taste of sugar, but without the unpleasant side effects on people’s health. One of these alternative sweeteners is sucralose.

What is sucralose?

Sucralose is an artificial sweetener synthesized in the laboratory from sucrose. It is prepared by selectively replacing three hydroxyl groups (-OH groups) with chlorine (Cl) atoms. The structure of sucralose, whose molecular formula is C ₁₂ H ₁₉ O ₈ Cl ₃ , is presented in the following figure:

As can be seen by comparing the chemical structures of sucrose and sucralose, these compounds are very closely related to each other. For example, both are substances with abundant polar groups that are highly soluble in water. However, from a chemical point of view, small differences in structure give rise to very different macroscopic properties.

Differences between sucrose and sucralose

sweetening power

Despite being the most widely used sweetener in the world, sucrose is actually not particularly sweet. In fact, many other natural carbohydrates are considerably sweeter than table sugar. The latter happens with sucralose, which has been shown to be up to 600 times sweeter than sucrose.

What does this mean?

This means that 1 gram of sucralose is capable of sweetening the same as 600 g of sucrose. In other words, we can replace more than a pound of sugar with less than a tablespoon of sucralose in our preparations.

caloric content

As if reducing the amount of sweetener required from 600g to just 1g isn’t good enough, there’s another even more important factor that makes sucralose an excellent sugar substitute for dieters without sacrificing their favorite desserts and sweets.

The point is that the substitution of hydroxyl groups for chlorine atoms in sucralose alters the shape of the molecule and prevents it from being absorbed in the intestine. Furthermore, this substance cannot be broken down either by the enzymes that our body produces (such as amylase, which is an enzyme that breaks down carbohydrates) or by the enzymes of the bacteria that we have in our digestive system.

The consequence of the above is that the vast majority of the sucralose that we ingest with our food is excreted unchanged and does not provide any calories as part of our diet. For this reason, sucralose is often said to be a non-caloric sweetener.

Instead, sucrose is metabolized in the body, first breaking down into its constituent monosaccharides. These are metabolized through glycolysis to become pyruvate, which, through the Krebs cycle and oxidative phosphorylation, are completely oxidized, releasing 3.87 kcal (or 3.87 Cal, which is the same) for each gram of sucrose ingested.

Thermal stability

Many of us are familiar with sugar and even more so with the product that is formed by heating sugar to high temperatures, that is, caramel. When heated, sucrose undergoes a series of chemical transformations called, collectively, caramelization. These reactions consist of a series of oxidation, dehydration, and polymerization processes that begin to occur at 160 °C. If the reaction is allowed to progress for a long time, the carbohydrate ends up being completely dehydrated, leaving behind mostly elemental carbon, a process called carbonization.

On the other hand, the breakdown of sucralose is very different. For starters, it begins to decompose at a much lower temperature of just 125 °C. In addition, due to the fact that it has chlorine in its structure, during the thermal decomposition of sucralose, polychlorinated aromatic compounds are also formed, as well as gaseous hydrogen chloride.

health effects

We already mentioned the effects that excessive consumption of sucrose in the diet can have. This can lead to obesity, the development of type II diabetes and also the development of metabolic syndrome. The latter is a condition that comprises a set of concurrent medical conditions such as hypertension, cardiovascular disease, high levels of triglycerides and uric acid in the blood, and type II diabetes.

On the other hand, sucralose, since it is not absorbed or metabolized by the body, poses virtually no direct health risk, especially when considering the small amounts of this sweetener needed to sweeten our foods compared to sugar from table.

However, not everything is perfect with sucralose since, as mentioned in the previous section, if it is cooked for too long or at a very high temperature, it can break down producing carcinogenic organic compounds that are very dangerous for health.

Summary of the differences between sucrose and sucralose

References

• Campos, AV (2017, February 28). Types of sugar: differences between glucose, fructose and sucrose . elconfidencial.com. https://www.elconfidencial.com/alma-corazon-vida/2017-02-14/tipos-azucar-que-es-glucosa-fructosa-sacarosa_1331040/
• de Oliveira, DN, de Menezes, M., & Catharino, RR (2015). Thermal degradation of sucralose: a combination of analytical methods to determine stability and chlorinated byproducts . Scientific Reports, 5 (1), 95–98. https://www.nature.com/articles/srep09598
• Sweeteners and sugar substitutes . (2021, October 5). MedlinePlus. https://medlineplus.gov/spanish/ency/article/007492.htm
• Sucralose, another way to sweeten food . (2019, December 26). GaeaPeople. https://www.solucionesparaladiabetes.com/magazine-diabetes/sucralosa-diabetes/
• Sabaté, J. (2019, February 13). Is sucralose a dangerous sweetener? ElDiario.es. https://www.eldiario.es/consumoclaro/cuidarse/sucralosa-edulcorante-peligroso_1_1701614.html
• Stanhope, KL (2015). Sugar consumption, metabolic disease and obesity: The state of the controversy . Critical Reviews in Clinical Laboratory Sciences, 53(1), 52–67. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822166/