Dextrin diastase

Starch -f Diastase Dextrin + Diastase Cellulose + Cellulase (Cytase)... 

Anselme Payen (Paris 17 January 1795-13 March 1871), at first director of a beet-sugar factory, was also professor of industrial chemistry in the Conservatoire des Arts et Metiers. He introduced the name cellulose (1839), published on starch (measuring the sizes of the granules of different kinds), dextrin, diastase, and many other subjects. His lectures were published. ... 

Diastase (or amylase) liver, etc., malt starch (amylum) maltose and dextrin 6-0 (liver) 5-2 (malt)... 

Diastase or amylase is formed when malt is produced by the germination of barley grains. Malt is therefore a good source of the enzyme. Diastase is also secreted by the salivary glands (when it is known as ptyalin), and also by the pancreas. Its function is to hydrolysef starch to a mixture of maltose and dextrin ... 

Dextrin is a hydrolysis product intermediate betw starches and sugars, such as dextrose (see next item). It does not give the blue iodine reaction of starch and is not fermentable, but is changed to maltose by the action of enzymes (diastase) and to dextrose by the action of acids... 

The temperature of the mixture must be maintained at 120° or 140° until all the stsrch is redissolved, when it should be suddenly elevated to 167°, as nearly as possible, in order to cause the most powerful action of which the diastase is capable. The thorough agitation of the mixture is then requisite, until the decomposition is almost complete this maybe ascertained liy the deep blue tint which the mixture acquires, and also by the action of iodine, which will communicate to the dextrin a purple or violet tint. 

This results from the transformation of starch by means of heat or by the action of dilute acid or diastase. It is prepared principally from potato, wheat or maize starch and rarely from rice or other exotic starches. Many varieties of dextrin, made in diverse ways, are sold under different names. It occurs as a fine powder, either wliite, dirty white, yellowish or light brown as granules, similar in appearance to gum arabic and as a thick syrup, more or less highly coloured and opaque. In general dextrin has a special odour and taste, which are particularly marked in the pulverulent varieties. It is soluble in water, but insoluble in alcohol. Its solution is strongly dextro-rotatory the value of [a]D varies from 173° to 2250,but is mostly about 200°. With iodine different dextrins give bluish violet to brownish red colorations (the colour is observed by adding the iodine solution drop by drop if the mass is mixed after the first drops are added, the colour disappears). 

Maltose is put on the market in the solid form, and as syrup, which usually contains also other sugars (especially glucose) and dextrin. Of this type, too, are malt extracts, including those which are used industrially —owing to the enzymes (diastases) they contain—to render starch soluble, e.g., Diamalt, Diastojor, etc. 

The above-mentioned substance was called diastase (Greek separation ) because of its ability to separate soluble dextrin from insoluble envelopes of starch grains. Diastase became a generally applied term for these enzyme mixtures until 1898, when Duclaux suggested the use of -ase in the name of an enzyme this classification procedure still holds today. 

Taka-diastase). After two months about 75% of the o-glucosidic linkages were ruptured. Fermentable sugar was removed and the dextrins were fractionated after concentration of the filtrate (Table XXI). Fractions III and IV contained amorphous disaccharides (non-fermentable or... 

Aspergillus oryzee is a yellowish-green to brown mold which secretes diastase, a valuable digestive ferment, having the power of converting starch into sugar and dextrin. For centuries the Japanese have employed this species in the preparation of rice mash for... 

An alternative view of the process is that the stable dextrin stage is reached when the whole of the amylose of starch is converted into maltose, and the amylo-pectin, which forms one-fiftli of the starch, is left, and this is only slowly converted into maltose by another ferment, dextri-nase, also present in diastase. 

Nature of the Changes during Mashing<—During the niaslihig process the. starch of the grist is acted upon by the diastase and the starch molecule broken down (page 6) into maltose, dextrin and intermediate malto-dextrins, one of the... 

In the early stages of fermentation there is a rapid development of yeast, for which the best temperature is about 17° to 21° C. the temperature rises as the operation proceeds, and the main fermentation in which the maltose and dextrose are transformed into alcohol occurs best at 26° to 30° C. At this temperature a secondary reaction also occurs, any dextrins which remain are acted upon by the diastase and gradually converted into fermentable sugars, which are then attacked by the yeast. The chief fermentation is over in about 48 hours, but the wort, now known as wash, is allowed to remain another day at 25° to 26° C. to complete the process. 

Conversion.—The conversion of starch results first in the so-called soluble starches, then in dextrin, then in maltose and finally in dextrose. The earlier stages of the process are not sharply defined from a chemical point of view and they are controlled entirely with a view to the special qualities desired in the product. As the conversion continues, mixtures of an unfer-mentable gum, dextrin, with varying proportions of maltose and dextrose are obtained. By carrying the process further, a yield of almost pure dextrose can be secured. This, of course, is the object in the processing of starch for the fermentation industry. The conversion of starch results either by the action of the enzyme, diastase, by boiling with dilute acids or by gentle roasting. The first two methods are used in the fermentation industry, often in conjunction with each other. 

Becent investigations have shown that by the action of diastase upon starch, four dextrins are produced 1st, Erythrodextrin which is colored red by iodine, and which is easily attacked by diastase 2d, Achto6dexlrin a, not colored by iodine partially convei d into sugar by diastase ... 

Diastase of Malt. Maltin. A mixture contg amy-lolytic enzymes obtained from malt. Converts at least 50 times its wt of potato starch into sugars (dextrin and maltose) in 30 minutes. 

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