Sucralose

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 ways to use sucrose and its synthetic derivatives for industrial use, 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.

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.

Production

Sucralose is manufactured by the selective chlorination of sucrose in a multistep synthesis, which substitutes three of the hydroxyl groups of sucrose with chlorine atoms. This chlorination is achieved by selective protection of a primary alcohol group, followed by chlorination of the partially acetylated sugar with excess chlorinating agent, and then by removal of the acetyl groups to give the desired sucralose product. A company realignment announced April 21, 2015 moved sucralose production from Tate & Lyle's plant on Jurong Island, Singapore to the recently reopened plant in McIntosh, Alabama.

Product uses

Sucralose is found in many food and beverage products, used because it is a no-calorie sweetener, does not promote dental cavities, is as safe for consumption by diabetics and nondiabetics, and does not 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 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 a highly heat-stable noncaloric sweetener, allowing it to be used in many recipes with little or no sugar. It 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 liquids. 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 baking 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.

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".

Health, safety, and regulation

Sucralose has been accepted as safe by several national and international food safety regulatory bodies, 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 9 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 ..."

Safety of consumption

Results from over a hundred animal and clinical studies in the FDA approval process unanimously indicated a lack of risk associated with sucralose consumption. When the estimated daily intake (EDI) is compared to the intake at which adverse effects are seen (known as the highest no adverse 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 (GI) tract and is directly excreted in the feces, while 11–27% of it is absorbed. The amount absorbed from the GI tract 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.

Potential effects on health

Despite being generally recognized as safe by regulatory agencies based on information from a multitude of large-scale and clinical studies, sucralose has been the subject of a few small-scale or animal studies attempting to determine yet-unknown effects on illnesses such as obesity, diabetes, and cancer.

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".

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 finally published on January 29 in the peer-reviewed International Journal of Occupational and Environmental Health. One study linked large doses of sucralose, equivalent to 11,450 packets (136 g) per day in a person (i.e., ~360 times the ADI of 5 mg/kg BW/day), to DNA damage in mice. Sucralose has not shown any DNA-damaging properties in DNA repair assays at normal consumption levels, and no evidence of carcinogenicity.

In a small-scale study of 17 obese test subjects, sucralose was found to affect glycemic and insulin responses, leading to an increase in peak plasma glucose concentration and insulin secretion rate. In a 2014 study, sucralose limited the growth of Bacteroides bacteria in vitro.

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 in the resulting smoke polychlorinated dibenzo-p-dioxins and other persistent organic pollutants.

Sucralose has been detected in natural waters. Studies indicate that this has virtually no impact on the early life development of certain animal species.