A-Dextrins

Maltodextrins [9050-36-6] are mixtures of saccharides with average DE values of <20 (12). They are rather soluble, have a bland taste, and are widely used in foods. A dextrin is a product obtained by depolymerization of a polysaccharide. 

This enzyme [EC 3.2.1.41] (also known as a-dextrin endo-1,6-o -glucosidase, pullulan 6-glucanohydrolase,... 

More exotic effects call for more exotic materials, and considerable effort has gone into formulating compositions that are both spectacular in effect and safe to produce and handle. Thus a 30 mm fountain might contain mealed (or hue) gunpowder, potassium nitrate, sulfur, charcoal, antimony trisulhde, barium nitrate, hue aluminium and flitter aluminium with a dextrin binder. This composition is certainly a good deal more complicated than that used for sparklers but is relatively safe to produce and gives a good burst of white sparks. 

Preparation of Anhydrous Chromium(III) Chloride. Perform the experiment in a fume cupboard Grind 5 g of charcoal into a fine powder in a mortar, mix it with 12.5 g of chromium(III) oxide, add a thick starch size or a dextrin solution in cold water, and make beads about 5 mm in diameter from the mixture. Put the beads onto a clay dish and dry them in a drying cabinet at 110-120 °C. Next put them into an iron crucible, cover them with the charcoal powder and a lid, and roast them. 

After the acid w are evaporated, the dried product is powdered and sieved. It can also be prepd by careful heating of dry starch. (Refs 6, 7, 8 10). If starch is hydrolyzed with Bacillus macerans, some crystalline products, such as a-dextrin, (CgHjQOj) are obtd (Ref 7). Crystallized products may also be prepd by decolorizing dextrin soln with animal charcoal and evaporating the product (Ref 10, p 346)... 

A) Dextrinated Lead Azide (abbrd as DLA), known also as Type l LA((/S). Its prepn and props are described under Lead Azide... 

Dextrins lodine/potassium iodide Blue-black spots (a-dextrins) 53... 

The rotations of the Schardinger dextrins were calculated from data of ref. 43. According to currently accepted nomenclature tetraamylose is Schardinger s a-dextrin, or cyclohexaamylose diamylose is an alcohol-containing complex of a-dextrin hexa-amylose is Schardingers /J-dextrin, or cycloheptaamylose. 

Maltotriose, III, 254 from arrow-root Starch, III, 274 from a-dextrins, III, 277 from soluble starch, III, 272 from starch, III, 288, 291, 308 Mandelic acid, effect on conductivity of boric acid, IV, 195... 

Takata, H., Takaha, T., Okada, S., Hizukuri, S., Takagi, M., and Imanaka, T. 1997. Production and some properties of a dextrin with anarrow size distribution by the cyclization reaction branching enzyme. J. Ferment. Bioeng.,84,119-123. 

Pullulanase carbohydrase Bacillus acidopullulyticus a-dextrin-6-glucanohydrolase 3.2.1.41... 

The latest International Union Biochemicals report includes an enzyme 3.2.1.41 a-dextrin endo-l,6-a-glucosidase, other names limit dextrinase, amylopectin 6-glucanohydrolase, pullulanase. 

Methylcyclopropene has also been prepared by reacting 3-chloro- or bromo-2-methylpropene with sodium amide or lithium di-isopropylamide in mineral oil and the product trapped in an a-dextrin matrix (3). In addition, it has been prepared in mineral oil using catalytic amounts of hexamethyldisilazane (4) as described below ... 

L-Iditol, f(j/o-inositol (m. p. 225°), stachyose, Schardinger a-dextrin Lactose... 

In the following experiment a thin paste of arrow-root starch was treated with malt a-amylase. The degree of hydrolysis was ascertained by titration with hypoiodite and n-glucose and maltose were determined by fermentative methods. After the fermentation, the average chain lengths of the a-dextrins was determined by titration with hypoiodite before and after complete hydrolysis with sulfuric acid. In Fig. 4, curve... 

Fig. 4.—Hydrolysis of arrow-root starch by malt a-amylase, 1, hydrolysis as calculated from reduction value II, average chain length of a-dextrins III, formation of maltose (and maltotriose) IV, formation of n-glucose.

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