Maize dextrins from

Smith and coworkers - have subjected starch dextrins to the classical techniques of structural carbohydrate chemistry. In one study, four commercial maize-dextrins were fractionated from aqueous ethanol to obtain a sub-fraction which was the most resistant to periodate oxidation. This material was then methylated, the product hydrolyzed, and the resulting methylated sugars analyzed by column chromatography. Table II shows the results. The complexity of the dextrin structure is shown by the fact that only components 1, 2, and 5 arise in any large proportion from the methylation of maize starch. It is of interest that no traces of a methyl... 

The only example of this technique applied to the amylose component is that already described, of the action of Z-enzyme on the /3-limit dextrin. In the case of amylopectin, enzymic methods enable a distinction to be made between the proposed laminated and highly ramified structures (I and III, in Fig. 1, page 352). The method used by Peat and coworkers101 involves the successive action of /3-amylase and R-enzyme on waxy maize starch. /3-Amylolysis will degrade A-chains down to two or three units from the 6 —> 1-a-D interchain linkages. These latter linkages will protect the... 

There have been several examinations of the structure of Nageli dextrin,405407 which is prepared by the prolonged action of acid on granular starch. In one study,405 there was separated from waxy maize a branched fraction that was resistant to pullulanase action. As this fraction contained some molecules having two branch points that were in close proximity, it was considered that this may have hindered hydrolysis, and that it could be of relevance to studies on the structure of the original amylopectin. 

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). 

The best dextrins, derived from good potato starch, exhibit a shining reflection, those which appear opaque being usually obtained from wheat or maize starch. 

Manufacture Dextrine is obtained by heating starch from wheat, corn (maize), potato or sweet potato in powder form to 200 270 0 Or 0 15. /... 

Dextrin is prepared by the incomplete hydrolysis of starch by heating in the dry state with or without the aid of suitable acids and buffers moisture may be added during heating. The PhEur 2005 specifies that dextrin is derived from maize (com) or potato starch. A specification for cassava is included in the USPNF 23. 

The specific rotation,, of the products of dextrinization is randomly estimated. This index is not of any special interest. As reported for a maize starch, [a] (and its variation) is nonuniformly dependent on the temperature of dextrinization. After a given time of heating, it increases together with temperature ofdextrinization (from about +160° at 120°Cto+198° at 230°C). Only dextrinization at 210°C causes a drastic decrease of [aJo as a function of the time of dextrinization in other cases, the variation of this index is small. The decrease of [a]o is interpreted as the result of the formation of new yS-D bonds by D-glucosyl residues. 

Fig. 22.— Relationship between Amylolytic Index, Reducing Sugars, and Solubility of Dextrin, and Time of Dextrinization of Maize Starch in the Process Involving Alum. [Curves from 1 to 5 correspond to temperatures of the process which decrease regularly from 180 to 140 ° in decimal ranges, respectively.]...

Manufacture. Dextrine is obtained by heating starch from wheat, corn (maize), potato or sweet potato in powder form to 200 270°C. Or 0.15-0.3% of nitric acid or 0.4-0.5% hydrochloric acid is added to the starch uniformly, which is well dried and heated to 100 120°C. The former product is called calcinatory dextrine and is brownish the latter is called acid process dextrine and white or yellowish. 

Dextrins may be produced from all of the commercial grain and tuber starches, but maize, potato, and tapioca starch are most commonly used. When conversions are carried out in the presence of an acid catalyst, hydrochloric acid is most often employed, because it is a strong acid, disperses uniformly through the starch, and tends to volatilize during the last stages of dextrinization, so that neutralization of the product may not be necessary. In the preparation of British Gums, an alkaline catalyst, such as sodium carbonate may sometimes be used. Details of the industrial processes have been described. ... 

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