The gelatinized starch is also called α- Starch. Dehydrate and dry the freshly prepared gelatinized starch slurry to obtain an amorphous powder that is easy to disperse and cool, namely "soluble α- Starch ".
Determination methods of starch gelatinization:
Optical microscopy, electron microscopy, light propagation, viscosity measurement, swelling and solubility measurement, enzyme analysis, nuclear magnetic resonance, laser light scattering, etc. Viscosity measurement, swelling and solubility measurement are commonly used in industry. 2、 The product of acid modified starch is called acid modified starch when the starch is treated with inorganic acid and its properties are changed below the gelatinization temperature.
Reaction mechanism:
In the process of treating starch with acid, acid is used as a glycosidic bond to hydrolyze starch molecules, and starch molecules become smaller. Starch granules are composed of amylose and amylopectin. The former has α- 1, 4 keys, the latter is divided by α- 1, 4 keys, and a small amount α- 1, 6 bonds, the two glycosidic bonds are difficult to be hydrolyzed by acid. Due to the influence of the crystalline structure of starch granules, the amylose molecules are combined into crystalline structure through hydrogen bonds. It is difficult for acid to penetrate α- 1, 4 bonds are not easily hydrolyzed by acid. The amylopectin molecules in the amorphous region of the granules α- 1, 4 keys α- 1 and 6 bonds are easy to be infiltrated by acid and hydrolyzed.
Process and principle:
Generally, concentrated starch slurry with solid content of about 36%~40% is used to prepare acid modified starch, which is heated to the gelatinization temperature (usually 40~60 ℃), inorganic acid is added and stirred for one hour or several hours.