1. Gelatinization
Gelatinized starch is generally surrounded by cell walls and exists in granular form. Such granules are insoluble in water and are not affected by amylase. However, starch granules will quickly absorb water and swell after heating. When the temperature rises to a certain level, the cell walls rupture, starch molecules dissolve, and form a viscous paste. This process is called "gelatinization". In short, gelatinization is the process of starch granules swelling and rupturing in a hot solution.
After starch is gelatinized, the amylase in the liquid can decompose it well, while the decomposition of ungelatinized starch takes a long time.The critical temperature at which starch granules quickly absorb water, swell and rupture to form a paste is called the gelatinization temperature.
The gelatinization temperatures of different excipients are different, which is caused by the different sizes and chemical compositions of starch granules of different grains. For example, the gelatinization temperature of rice starch is 80-85°C, the gelatinization temperature of corn starch is 68-78°C, and the gelatinization temperature of wheat starch is 57-70°C.
(ii) Liquefaction
Liquefaction, α-amylase rapidly decomposes the long starch chains (amylose and amylopectin) composed of glucose residues into short chains to form low molecular weight dextrins, thereby rapidly reducing the viscosity of the gelatinized mash. This process is called "liquefaction", and the liquefaction process is a biochemical reaction process.
The meaning of liquefaction is to reduce the viscosity of the gelatinized starch liquid through the action of α-amylase. Although liquefaction cannot form a lot of sugars, its action products are conducive to the further action of saccharifying amylase. Good liquefaction creates conditions for saccharification.
(III) Saccharification
