Classification of denatured starch, why does starch need to be denatured
There are many types of modified starch and their applications are widespread, so there are also many classification methods. According to the modification methods of modified starch, it can be divided into physical modification, chemical modification, enzymatic modification, and composite modification. According to the production route of modified starch, it can also be divided into dry method, wet method or organic solvent method, extrusion method, or drum drying method. It can also be classified according to the source of starch before denaturation, such as potato denatured starch, corn denatured starch, wheat denatured starch, and so on. According to the application or function of starch, there are also oxidized starch, acid hydrolyzed starch, cross-linked starch, cationic starch, phospholipid starch, carboxymethyl starch, carboxalkyl starch, etc.
Why does starch denature?
To understand why starch undergoes denaturation, it is first necessary to understand the properties of starch:
In terms of physical properties, starch has a certain adsorption capacity, which can adsorb many organic or inorganic compounds, and has different adsorption characteristics according to molecular structure; Starch has a certain solubility in hot water, but is insoluble in cold water; In addition, the gelatinization characteristics and retrogradation (aging) phenomenon are also important properties of starch.
In terms of chemical properties, starch is a polymer of glucose, so it has many similar properties to glucose, but also some unique properties. Generally, the methods for utilizing the chemical properties of starch are mainly hydrolysis and denaturation.
Then return to the topic of why starch denatures:
First of all, starch with different structures has different adsorbability, so modification can change the molecular structure of starch to provide it with adsorbability suitable for different situations.
Starch is generally insoluble in cold water, but some chemically modified starch can be soluble in cold water.
A large portion of the chemical properties of starch are applied using modified starch, which is modified by reacting with specific chemical reagents. For example, various chemical reactions such as oxidation, esterification, etherification, alkylation, and cross-linking can occur under certain conditions in the upstream free alcohol hydroxyl groups of glucose residues in starch molecules, resulting in various types of modified starch or starch derivatives.