Sucralose

Sucralose is an artificial sweetener and sugar substitute. The majority of ingested sucralose is not broken down by the body, so it is noncaloric. In the European Union, it is also known under the E number E955. It is produced by chlorination of sucrose, selectively replacing three of the hydroxy groups to give a 1,6-dichloro-1,6-dideoxyfructose–4-chloro-4-deoxygalactose disaccharide. Sucralose is about 320 to 1,000 times sweeter than sucrose, three times as sweet as both aspartame and acesulfame potassium, and twice as sweet as sodium saccharin. Evidence of benefit is lacking for long-term weight loss with some data supporting weight gain and heart disease risks.
While sucralose is largely considered shelf-stable and safe for use at elevated temperatures (such as in baked goods), there is some evidence that it begins to break down at temperatures above 119 degrees Celsius. The commercial success of sucralose-based products stems from its favorable comparison to other low-calorie sweeteners in terms of taste, stability, and safety. It is commonly sold under the Splenda brand name. Canderel Yellow also contains sucralose, but the original Canderel and Green Canderel do not.
Uses.
Sucralose is used in many food and beverage products because it is a no-calorie sweetener, does not promote dental cavities, is safe for consumption by diabetics and nondiabetics, and does not affect insulin levels, although the powdered form of sucralose-based sweetener product Splenda (as most other powdered sucralose products) contains 95% (by volume) bulking agents dextrose and maltodextrin that do affect insulin levels. Sucralose is used as a replacement for, or in combination with, other artificial or natural sweeteners such as aspartame, acesulfame potassium or high-fructose corn syrup. Sucralose is used in products such as candy, breakfast bars, coffee pods, and soft drinks. It is also used in canned fruits wherein water and sucralose take the place of much higher calorie corn syrup-based additives. Sucralose mixed with maltodextrin or dextrose (both made from corn) as bulking agents is sold internationally by McNeil Nutritionals under the Splenda brand name. In the United States and Canada, this blend is increasingly found in restaurants, in yellow packets, in contrast to the blue packets commonly used by aspartame and the pink packets used by those containing saccharin sweeteners; in Canada, though, yellow packets are also associated with the SugarTwin brand of cyclamate sweetener.
Cooking.
Sucralose is available in a granulated form that allows for same-volume substitution with sugar. This mix of granulated sucralose includes fillers, all of which rapidly dissolve in water. While the granulated sucralose provides apparent volume-for-volume sweetness, the texture in baked products may be noticeably different. Sucralose is not hygroscopic, which can lead to baked goods that are noticeably drier and manifest a less dense texture than those made with sucrose. Unlike sucrose, which melts when baked at high temperatures, sucralose maintains its granular structure when subjected to dry, high heat (e.g., in a 350 °F or 180 °C oven). Furthermore, in its pure state, sucralose begins to decompose at 119 °C or 246 °F. Thus, in some recipes, such as "crème brûlée", which require sugar sprinkled on top to partially or fully melt and crystallize, substituting sucralose will not result in the same surface texture, crispness, or crystalline structure.
Health effects.
Sucralose has been accepted as safe by several food safety regulatory bodies worldwide, including the FDA, The Joint FAO/WHO Expert Committee Report on Food Additives, the European Union's Scientific Committee on Food, Health Protection Branch of Health and Welfare Canada, and Food Standards Australia New Zealand. According to the Canadian Diabetes Association, the amount of sucralose that can be consumed over a person's lifetime without any adverse effects is 900 mg per kg of body weight per day.
"In determining the safety of sucralose, the FDA reviewed data from more than 110 studies in humans and animals. Many of the studies were designed to identify possible toxic effects, including carcinogenic, reproductive, and neurological effects. No such effects were found, and FDA's approval is based on the finding that sucralose is safe for human consumption." For example, McNeil Nutritional LLC studies submitted as part of its U.S. FDA Food Additive Petition 7A3987 indicated that "in the 2-year rodent bioassays ... there was no evidence of carcinogenic activity for either sucralose or its hydrolysis products ..."
Results from studies in the FDA approval process indicated a lack of risk associated with eating sucralose. When the estimated daily intake (EDI) is compared to the intake at which adverse effects are seen (known as the "highest no-effects limit", or HNEL at 1500 mg/kg BW/day, a large margin of safety exists. The bulk of sucralose ingested is not absorbed by the gastrointestinal tract (gut) and is directly excreted in the feces, while 11–27% of it is absorbed. The amount absorbed from the gut is largely removed from the blood stream by the kidneys and eliminated in the urine, with 20–30% of the absorbed sucralose being metabolized. This means that only between 2–8% of sucralose consumed is metabolized, on average.
Animal studies suggest that there might be a link between sucralose and a reduction in beneficial gut bacteria, with concerns this could result in health issues. Both human and rodent studies indicate that sucralose may affect glucose and insulin levels and is not a biologically inert compound.
Research in 2019 revealed that when sucralose is heated to ≥248 °F (120 °C) it may dechlorinate and decompose into compounds that are harmful enough to risk consumer health. The risk and intensity of this adverse effect is suspected to increase with rising temperatures. The German Federal Institute for Risk Assessment (BfR) published an advisory warning that cooking with sucralose could possibly lead to the creation of potentially carcinogenic chloropropanols, polychlorinated dibenzodioxins and polychlorinated dibenzofurans. The BfR recommended that manufactures and the general public avoid baking, roasting, or deep frying any sucralose-containing foods until a more conclusive safety report is available. Furthermore, adding sucralose to food that has not cooled was discouraged, as was buying sucralose-containing canned foods and baked goods. Since the boiling point of water is 212 °F there is no advisory on boiled foods or sucralose-containing beverages.
A review article suggests there is a link between sucralose consumption and insulin resistance in susceptible individuals, due to sucralose changing the composition of gut microbiota.
The Center for Science in the Public Interest, a consumer advocacy group for food products, downgraded sucralose from "Safe" to "Caution" in June 2013, citing an unpublished study linking sucralose consumption with leukemia risk in rats. The study has been criticized as being poorly executed and reported. The study was published on 29 January 2016 in the peer-reviewed "International Journal of Occupational and Environmental Health," and the Center for Science in the Public Interest downgraded sucralose from "Caution" to "Avoid".
History.
Sucralose was discovered in 1976 by scientists from Tate & Lyle, working with researchers Leslie Hough and Shashikant Phadnis at Queen Elizabeth College (now part of King's College London). While researching novel uses of sucrose and its synthetic derivatives, Phadnis was told to "test" a chlorinated sugar compound. Phadnis thought Hough asked him to "taste" it, so he did. He found the compound to be exceptionally sweet.
Tate & Lyle patented the substance in 1976; as of 2008, the only remaining patents concern specific manufacturing processes.
A Duke University animal study funded by the Sugar Association found evidence that doses of Splenda (containing ~1% sucralose and ~99% maltodextrin by weight) between 100 and 1000 mg/kg BW/day, containing sucralose at 1.1 to 11 mg/kg BW/day, fed to rats reduced fecal microflora, increased the pH level in the intestines, contributed to increases in body weight, and increased levels of P-glycoprotein (P-gp). These effects have not been reported in humans. An expert panel, including scientists from Duke University, Rutgers University, New York Medical College, Harvard School of Public Health, and Columbia University reported in "Regulatory Toxicology and Pharmacology" that the Duke study was "not scientifically rigorous and is deficient in several critical areas that preclude reliable interpretation of the study results".
Sucralose was first approved for use in Canada in 1991. Subsequent approvals came in Australia in 1993, in New Zealand in 1996, in the United States in 1998, and in the European Union in 2004. By 2008, it had been approved in over 80 countries, including Mexico, Brazil, China, India, and Japan. In 2006, the US Food and Drug Administration amended the regulations for foods to include sucralose as a "non-nutritive sweetener" in food. In May 2008, Fusion Nutraceuticals launched a generic product to the market, using Tate & Lyle patents.
In April 2015 PepsiCo announced that it would be moving from aspartame to sucralose for most of its diet drinks in the US, due to sales of Diet Pepsi falling by more than 5% in the US. PepsiCo says its decision is a commercial one - responding to consumer preferences.
In February 2018 PepsiCo went back to using aspartame in Diet Pepsi because of an 8% drop in sales for the previous year.
Chemistry and production.
Sucralose is a disaccharide composed of 1,6-dichloro-1,6-dideoxyfructose and 4-chloro-4-deoxygalactose. It is synthesized by the selective chlorination of sucrose in a multistep route that substitutes three specific hydroxyl groups with chlorine atoms. This chlorination is achieved by selective protection of one of the primary alcohols as an ester (acetate or benzoate, followed by chlorination with an excess of any of several chlorinating agent to replace the two remaining primary alcohols and one of the secondary alcohols, and finally deprotection by hydrolysis of the ester.
Packaging and storage.
Pure sucralose is sold in bulk, but not in quantities suitable for individual use, although some highly concentrated sucralose–water blends are available online. These concentrates contain one part sucralose for each two parts water. A quarter teaspoon of concentrate substitutes for one cup of sugar. Pure, dry sucralose undergoes some decomposition at elevated temperatures. In solution or blended with maltodextrin, it is slightly more stable. Most products containing sucralose add fillers and additional sweetener to bring the product to the approximate volume and texture of an equivalent amount of sugar.
Effect on caloric content.
Though sucralose contains no calories, products that contain fillers, such as maltodextrin and/or dextrose, add about 2–4 calories per teaspoon or individual packet, depending on the product, the fillers used, brand, and the intended use of the product. The US Food and Drug Administration (FDA) allows for any product containing fewer than five calories per serving to be labeled as "zero calories".
One study suggests that artificial sweeteners may not fully activate the brain's "food reward pathways" as sugar does, stating that, because sweetener does not provide full satisfaction, the user may search for, and then eat, additional high-calorie foods leading to weight gain.
Environmental effects.
According to one study, sucralose is digestible by a number of microorganisms and is broken down once released into the environment. However, measurements by the Swedish Environmental Research Institute have shown sewage treatment has little effect on sucralose, which is present in wastewater effluents at levels of several μg/l (ppb). No ecotoxicological effects are known at such levels, but the Swedish Environmental Protection Agency warns a continuous increase in levels may occur if the compound is only slowly degraded in nature. When heated to very high temperatures (over 350 °C or 662 °F) in metal containers, sucralose can produce polychlorinated dibenzo-p-dioxins and other persistent organic pollutants in the resulting smoke.
Sucralose has been detected in natural waters. Studies indicate that this has virtually no impact on the early life development of certain animal species, but the impact on other species remains unknown.