Крахмал

Химические свойства

Starch occurs as an odorless and tasteless, fine, white to off-white powder. It consists of very small spherical or ovoid granules or grains whose size and shape are characteristic for each botanical variety.

Использование

corn starch is used as a thickener in cosmetics and in face powders. Corn starch absorbs water and is soothing to the skin. It can cause allergic reactions such as inflamed eyes, stuffy nose, and perennial hay fever. A natural material obtained from corn kernels.

Определение

A polysaccharide that occurs exclusively in plants. Starches are extracted commercially from maize, wheat, barley, rice, potatoes, and sorghum. The starches are storage reservoirs for plants; they can be broken down by enzymes to simple sugars and then metabolized to supply energy needs. Starch is a dietary component of animals.
Starch is not a single molecule but a mixture of amylose (water-soluble, blue color with iodine) and amylopectin (not water-soluble, violet color with iodine). The composition is amylose 10–20%, amylopectin 80–90%.

Методы производства

Starch is extracted from plant sources with specific processes according to the botanical origin. Typical production steps are steeping (corn), wet milling (corn, potato), dry milling (wheat), or sieving and physical separation with hydrocyclones. The last production step is usually a centrifugal separation from the starch slurry followed by drying with hot air. The starch separation process may use sulfur dioxide or peroxides as a processing aid, improving the separation process and the microbial quality of the final product.

Общее описание

Fine, white, odorless powder. Note that granules from different vegetable sources vary in shape, size, and general appearance. A mixture of the carbohydrate polymers amylose amylopectin varying according to the vegetable source. Principally used for food.

Профиль реактивности

Starch is combustible. Presents a dust explosion hazard if dispersed as a fine dust in air in sufficient concentrations. Granules swell greatly in water and produce a colloidal suspension. Incompatible with oxidizing agents, acids, iodine, bases. Reacts with nitric acid/sulfuric acid mixtures to give nitroStarch, an explosive.

Опасность

Dermatitis. Questionable carcinogen.

Профиль безопасности

A nuisance dust. Mildly toxic by intraperitoneal route. A skin irritant. An allergen. Flammable when exposed to flame; can react with oxidizing materials. Moderately explosive when exposed to flame.

Безопасность

Starch is an edible food substance, considered a food ingredient and not a food additive. It is regarded as an essentially nontoxic and nonirritant material. Starch is therefore widely used as an excipient in pharmaceutical formulations.
Both amylose and amylopectin have been evaluated as safe and without limitation for daily intake. Allergic reactions to starch are extremely rare and individuals apparently allergic to one particular starch may not experience adverse effects with a starch from a different botanical source. The wheat proteins (gluten) are problematic for conditions such as celiac disease.
Contamination of surgical wounds with the starch glove powder used by surgeons has resulted in the development of granulomatous lesions.
LD50 (mouse, IP): 6.6 g/kg

хранилище

Dry starch is stable if protected from high humidity. Starch is considered to be chemically and microbiologically inert under normal storage conditions. Starch solutions or pastes are physically unstable and are readily metabolized by microorganisms; they should therefore be freshly prepared when used for wet granulation.
Starch should be stored in an airtight container in a cool, dry place.

Несовместимости

Starch is incompatible with strongly oxidizing substances. Colored inclusion compounds are formed with iodine.

Регуляторный статус

GRAS listed. Included in the FDA Inactive Ingredients Database (buccal tablets, oral capsules, powders, suspensions and tablets; topical preparations; and vaginal tablets). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.