alpha-Cyclodextrin

alpha-Cyclodextrin (α-dextrin, α-cyclodextrin, α-CD, alphadextrin, alpha cyclodextrin (dietary fiber)) is a polysaccharide of six glucose units that are covalently attached end to end via α-1, 4 linkages. This fiber is sold under the brand names, "Alpha-Fibe" and "Calorease". Alpha-Fibe is the original product that contains this unique fiber, introduced to the worldwide nutritional supplement market by Bio-Form Essentials in 2007. Soho Flordis International became the patent Assignee as of March 30, 2012 and launched the brand Calorease in 2013.

FBCx is not an ingredient, only an abbreviation, and is not part of the scientific name. The abbreviation FBCx, stands for "Fat Binding Complexer" and can be associated with the brand names, "Alpha-Fibe" and "Calorease". There are two other naturally occurring cyclodextrins, β (beta) - and γ (gamma) -, which contain seven and eight glucose units respectively. In water, these fibers take on a toroid or truncated cone configuration. In aqueous medium, the exterior surface of cyclodextrins is hydrophilic while the interior core is hydrophobic. This allows for the formation of guest-host relationships with small hydrophobic molecules. McGowan et al., for example, demonstrated that α-cyclodextrin was very effective at solubilizing the free fatty acids that are generated in the colorimetric determination of triglycerides. Shimada et al. have demonstrated that at an oil:water interface α-cyclodextrin “threads” onto fatty acids in a manner analogous to threading beads onto a string. According to these authors, the number of cyclodextrin molecules per fatty acid appears to be dependent upon the length of the fatty acids that are involved. Due to the small pore size it was generally believed that α-cyclodextrin could not form a complex with triglyceride. However, Artiss et al. demonstrated that α-cyclodextrin could complex triglyceride and at ratios that are significantly different from the 1:1 that is typical for dietary fibers. The ratio for α-cyclodextrin is actually closer to 1:9 (fiber:fat ratio). Trichard et al. have demonstrated that α-cyclodextrin and soybean oil can form porous beads that may find utility in delivering water-insoluble pharmaceuticals.

Applications

α-Cyclodextrin is a multifunctional, soluble dietary fiber marketed for use as a fiber ingredient, an odor or flavor masking agent as well as for emulsification applications. It is registered as a dietary fiber in the European Union since 2008.

α-Cyclodextrin is marketed for a range of medical, healthcare and food and beverage applications which rely on its ability to bind to fats and reduce their bioavailability both in the body and in food and beverage products. As a fiber dietary supplement,α-cyclodextrin binds to fat when taken with a meal and is a natural alternative to other synthetic anti-obesity medications. α-Cyclodextrin has the unique ability among known fibers to bind nine times its own weight in fat. Although many dietary fibers appear to bind fat on a 1:1 ratio α-cyclodextrin is the only one that binds on a 1:9 (fiber:fat) ratio. As the molecular weight of the fiber and triglycerides are about the same, it would appear to follow that the cyclodextrin is actually forming a layer on the surface of the fat droplets. Bochot et al.. have lent evidence to this theory by demonstrating that it is possible to produce “beads” with oily compartments by mixing an aqueous solution of the fiber with soybean oil albeit under somewhat more vigorous conditions than occur in the human stomach. This high ratio of binding makes α-cyclodextrin practical as a weight loss supplement.

In order for fat or triglyceride to be absorbed it must first be digested by the pancreatic enzyme lipase. If the lipase activity is decreased then the dietary triglyceride passes through to the large bowel without being absorbed. There are, however, side effects to the use of lipase inhibitors: if dietary fat is not restricted, the free fat that passes into the large bowel will precipitate side effects. Unlike lipase inhibitors alpha-cyclodextrin forms a stable complex with the dietary fat which prevents lipase from digesting the triglyceride and the normal gut flora from using it as a carbon source, thus preventing the side effects of the lipase inhibitors.

There are no known negative side effects except for gas since it is a dietary fiber, if you take it without having fat in your meal.

Animal and human studies are consistent with each other in demonstrating the positive benefits of taking alpha-cyclodextrin fiber.

• Lower blood (LDL or bad) low-density lipoprotein cholesterol levels
• Lower blood triglyceride levels
• Preferentially lowers blood saturated fat and trans fat levels
• Increased insulin sensitivity
• Increased leptin sensitivity – increased satiety
• Improved glycemic index of foods and improved glycemic control

Due to its surface active properties, α-cyclodextrin can also be used as an emulsifying fiber, for example in mayonnaise. It stabilizes oil-in-water emulsions very efficiently. The three-dimensional, donut-shaped cyclodextrins have a hydrophobic cavity inside and a hydrophilic cover on the outside. A fatty acid tail of triglycerides is attracted by the cavity and encapsulated there. This leads to the build-up of a surfactant-like structure which has emulsion-stabilizing properties. Depending on the oil-to-water ratio and the amount of α-cyclodextrin used, the viscosity, and therefore the organoleptic properties, of the emulsion are altered. From ketchup-like viscosity to icing-like viscosity, all grades can be adjusted. Often with significant less fat content and thus reduced calories. Furthermore, stable emulsions are feasible even at elevated temperatures.

α-Cyclodextrin can also be used as whipping fiber, for example in desserts and confectionery applications. Tests showed that alpha cyclodextrins can cause a volume effect in various different food compositions with or without fat and at a very broad pH range. This can be used for fat free or fat containing dessert compositions and for the reduction or the replacement of egg white in confectionery and bakery applications.

Structure

α-Cyclodextrin is a naturally occurring, cyclic oligosaccharide, enzymatically produced from starch. It is a well-defined, chemically pure substance consisting of six linked glucose units.

Synthesis

Cyclodextrins are natural starch-conversion products. For industrial use, they are manufactured by enzymatic degradation from vegetable raw materials, such as corn or potatoes. First the starch is liquified either by heat treatment or using α-amylase. Then cyclodextrin glycosyltransferase (CGTase) is added for enzymatic conversion. CGTases can synthesize all forms of cyclodextrins, thus for the production of the α-cyclodextrin, one specific enzyme must be used.