D-Фруктоза

Химические свойства

White Cyrstalline Solid

История

Despite this ubiquity, fructose remained a noncommercial product until the 1980s because of the expense involved in its isolation and the care required for its handling. The development of technologies for preparing fructose from glucose in the isomerized mixture led to a greater availability of pure, crystalline fructose in the 1970s. However, the price for pure fructose was high enough in 1981 that the product was not competitive with sucrose and corn syrups as a commercial sweetener. With the entry of corn wet-milling companies into the crystalline fructose market in the late 1980s, raw material economies and enlarged manufacturing scale led to a nearly 10-fold production increase within a five-year period, making fructose prices competitive with other sweeteners for specific applications.

Использование

D-Fructose occurs in a large number of fruits, honey, and as the sole sugar in bull and human semen

Методы производства

Fructose, a monosaccharide sugar, occurs naturally in honey and a large number of fruits. It may be prepared from inulin, dextrose, or sucrose by a number of methods. Commercially, fructose is mainly manufactured by crystallization from high-fructose syrup derived from hydrolyzed and isomerized cereal starch or cane and beet sugar.

Определение

A sugar found in fruit juices, honey, and cane sugar. It is a ketohexose, existing in a pyranose form when free. In combination (e.g. in sucrose) it exists in the furanose form.

Общее описание

Fructose is a monosaccharide. It is present in fruits and vegetables. Fructose is the major carbohydrate in the diet. It binds with glucose to form sucrose. Excessive intake of fructose is associated with obesity, type 2 diabetes and cardiovascular disease.

Безопасность

Although it is absorbed more slowly than dextrose from the gastrointestinal tract, fructose is metabolized more rapidly. Metabolism of fructose occurs mainly in the liver, where it is converted partially to dextrose and the metabolites lactic acid and pyruvic acid. Entry into the liver and subsequent phosphorylation is insulinindependent. Further metabolism occurs by way of a variety of metabolic pathways. In healthy and well regulated diabetics, glycogenesis (glucose stored as glycogen) predominates.
Excessive oral fructose consumption (>75 g daily) in the absence of dietary dextrose in any form (e.g. sucrose, starch, dextrin, etc.) may cause malabsorption in susceptible individuals, which may result in flatulence, abdominal pain, and diarrhea. Except in patients with hereditary fructose intolerance, there is no evidence to indicate that oral fructose intake at current levels is a risk factor in any particular disease, other than dental caries.

хранилище

Fructose is hygroscopic and absorbs significant amounts of moisture at relative humidities greater than 60%. Goods stored in the original sealed packaging at temperatures below 25°C and a relative humidity of less than 60% can be expected to retain stability for at least 12 months.
Aqueous solutions are most stable at pH 3–4 and temperatures of 4–70°C; they may be sterilized by autoclaving.

Методы очистки

Dissolve D(-)-fructose in an equal weight of water (charcoal, previously washed with water to remove any soluble material), filter and evaporate under reduced pressure at 45-50o to give a syrup containing 90% of fructose. After cooling to 40o, the syrup is seeded and kept at this temperature for 20-30hours with occasional stirring. The crystals are removed by centrifugation, washed with a small quantity of water and dried to constant weight under a vacuum over conc H2SO4. For higher purity, this material is recrystallised from 50% aqueous ethanol [Tsuzuki et al. J Am Chem Soc 72 1071 1950]. [Beilstein 31 H 321, 1 IV 4401.]

Несовместимости

Incompatible with strong acids or alkalis, forming a brown coloration. In the aldehyde form, fructose can react with amines, amino acids, peptides, and proteins. Fructose may cause browning of tablets containing amines.

Регуляторный статус

Included in the FDA Inactive Ingredients Database (oral solutions, syrup, and suspensions; rectal preparations; intravenous infusions). Included in the Canadian List of Acceptable Non-medicinal Ingredients.