Acid-Treated Starches

Acid modified, corn starch Acid-treated starch Corn flour, hydrochloric acid modified Starch, acid hydrolyzed Starch, acid-modified Starch, acid-treated Starch, thin-boiling Wheat starch, acid modified. 

Treated with starch. b Treated with ascorbic acid. 

To nitrate starch, Hugh treated it with an anhydrous mixture of nitric acid, sulphuric acid and oleum to obtain a product that very probably contained 13.3-13.5% N. Hugh s plant was destroyed as the result of an explosion, and the manufacture and application of Hugh s powder was abandoned. Further development of nitrostarch was then taken up by du Pont [25]. In 1905 this company introduced a low-freezing explosive Nyalite . A similar low-freezing explosive material Arctic , introduced by the same firm in 1907, was manufactured for the next decade. Both contained nitrostarch. 

Further, the hydrolysis of starch nitrate in acids containing little or no sulphuric acid does not proceed to such a large extent as is usual when starch is treated with mixtures of high sulphuric acid content. 

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... 

If a dilute solution of starch is treated at a suitable temperature with dilute mineral acid and the degree of hydrolysis a is calculated from the number of reducing groups set free, we find that the values of... 

Acid conversions when starch is treated with an acid such as HCI or H2SO4 at 40-60°C (commonly a starch slurry with 35-40% solids is treated with 0.2-0.5 N HCI for a few hours). Following the acid conversion, the acid is neutralized. In this process, the DP value decreases (and several physical properties are modified). Although chemical studies show that the a-D-(1- 4) links are more sensitive to hydrolysis than a-D-(1->6) links, it was determined that due to starch crystallinity more a-D-(1->6) links are hydrolyzed [55]. This happens because the a-D-(1 6) links are in the amorphous regions and they are more accessible to the reagent (less hydrogen bonds). This explains why the DP of amylose is reduced less than that of the amylopectin component. 

When starch is treated with hot alkaline solutions, it behaves in the manner to be expected of a material composed of an alkali-labile fraction and an alkali-stable fraction. Starches from different sources vary in the relative amounts of these two components, and, therefore, starches can be characterized by their alkali lability. Alkali lability of a starch can be expressed as its alkali number, which is an empirical expression of the acids produced from the terminal, reducing group by the action of alkali. The alkali number (and, therefore, the alkali lability) increases progressively during acid hydrolysis. - Hence, the alkali number is an index of molecular size for linear molecules. 

Hexa-nitro-starch is the product chiefly formed when 40 grms. of dry starch are treated with 400 grms. of nitric acid, specific gravity 1.501, and allowed to stand in contact for twenty-four hours 200 grms. of this mixture are then poured into 600 c.c. of sulphuric acid of 66° B. The result of this manipulation is a white precipitate, which contains 13.52-13.23 and 13.22 per cent, nitrogen and consists, therefore, of a mixture of penta- and hexa-nitro-starch. 

Hydroxy ethylated, acid-treated, oxidized starch Bondagel E-1000 + E-125 or SynChropak lOOOA-(-2 X 500A DMSO and H O mixture with or without buffer MW, operatii study... 

Products obtained by the action of oxidizing agents on raw starches are of considerable industrial importance, particularly as sizing materials, but their chemical natures are still unknown. Because of the increased fluidity of dispersions of oxidized starches as compared with untreated starches, they are classified with acid-treated ( acid-modified O starches as Hhin-boiling starches. In addition they produce clearer solutions with a lower... 

Transfer 5 ml of test solution to a 50 ml beaker and add a few drops of starch solution. Mix the solution and then acidify with dilute sulfuric acid. Treat the blank in a similar manner. When iodine is present in the sample, the characteristic blue colour of starch iodide will be developed in the test solution compared with the colourless blank solution. 

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