Starch acid-modified

In industrial production of acid-modified starches, a 40% slurry of normal com starch or waxy maize starch is acidified with hydrochloric or sulfuric acid at 25—55°C. Reaction time is controlled by measuring loss of viscosity and may vary from 6 to 24 hs. For product reproducibiUty, it is necessary to strictly control the type of starch, its concentration, the type of acid and its concentration, the temperature, and time of reaction. Viscosity is plotted versus time, and when the desired amount of thinning is attained the mixture is neutralized with soda ash or dilute sodium hydroxide. The acid-modified starch is then filtered and dried. If the starch is washed with a nonaqueous solvent (89), gelling time is reduced, but such drying is seldom used. Acid treatment may be used in conjunction with preparation of starch ethers (90), cationic starches, or cross-linked starches. Acid treatment of 34 different rice starches has been reported (91), as well as acidic hydrolysis of wheat and com starches followed by hydroxypropylation for the purpose of preparing thin-hoiling and nongelling adhesives (92). 

Acid-modified starches are used in the manufacture of gum candies because they form hot concentrated pastes that form strong gels on cooling. ThermaUzed starches are used in foods to bind and carry flavors and colors. Sweetening agents (com symp, HFCS) are made from starch by enzymatic or acid treatment as previously noted. 

Polysaccharides (e.g., dextran, inulin, hyaluronic acid, modified starch) [255-259] ... 

Converted starches, also called thin-boiling starches, are produced by degradation of the starch chains into small segments. They can be cooked in water at higher concentrations than native starches. Low-viscosity starches are needed in applications where a high solid starch paste with a pumpable and workable viscosity is required. There are four classes of commercial converted starches dextrins (hydrolysis in solid-state) acid-modified starches (hydrolysis in a slurry) oxidized starches and enzymically depolymerized starches. 

Acid-modified starches are made by heating and stirring concentrated starch slurry with an acid at a temperature which is below the gelatinization temperature. When the desired viscosity or degree of conversion is reached, the acid is neutralized. Acid-modified starches are used in the food industry (candy). 

Depolymerization (Thin-Boiling, or Acid-Modified Starch) This treatment results in partial depolymerization, causing a reduction in viscosity. Any of these treatments may be used in combination with the other treatments that follow. 

Acid-Insoluble Ash, 748 Acidity Determination by Iodometric Method (Flavor Chemicals), 565 Acid-Modified Starch, 159 Acid Number (Rosins and Related Substances), 832... 

Poly(vinyl alcohol) may also be added if water resistance is required. Another formulation that does not require cooking to develop its adhesive characteristic is based on the cold, caustic conversion of an acid-modified starch (75 fluidity) (fi). Clay filler may be added to any case or carton sealing adhesive if the board being glued is too porous. 

The ease with which the ETHYLEX Gums can be slurried and cooked is another important property. They gelatinize over a significantly shorter and lower temperature range than acid modified 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. 

The X-ray diffraction analysis indicated that during chemical modification process, several crystalline structures of native starch were destroyed, and a new structure of organic acid-modified starch was formed (Figure 7.3). The diffraction peaks for StM and CMSt look like a V-type crystalline structure. According to the literature data [92], there can be observed a typical A-style crystallinity in the native corn starch. This... 

According to the X-ray diffraction analysis, organic acid modified starch microparticles CMSt presented an amorphous characteristic, but some crystalline peaks at around 20 = 20 were also evidenced. 

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