Waxy corn starch, with a amylopectin content of over 95%, is a type of polysaccharide substance with varying molecular weights, with a degree of polymerization between 600 and 6000 and a degree of polymerization between 20 and 25 for side chains. Starch particles are arranged radially by linear and branched starch molecules, with alternating structures of crystalline and amorphous regions. Waxy corn starch granules are composed of highly branched molecules arranged radially, in which side chains gather together to form a double helix structure, and the crystalline region of starch granules is formed through hydrogen bond association;
In addition, the branching part of the chain segment does not participate in the formation of microcrystalline bundles, which is an amorphous region. Compared with ordinary varieties of starch, the crystal regions of waxy corn starch particles are arranged loosely and not tightly, making it easier for hot gas, water, and other substances to enter the microcrystalline bundles. This reduces the bonding force of oxygen bonds between chains, changes the structure of the crystalline region of the starch powder, and reduces crystallinity, transforming some crystalline regions into amorphous regions, making it prone to biochemical reactions.
Waxy corn starch is widely used in various industries, but almost all require heating and gelatinization before use. The properties of the gelatinized starch, such as dot size, transparency, shear resistance, and retrogradation, have a significant impact on its application effect. Amylopectin in waxy corn starch exists in the form of double helix, forms crystal area through hydrogen bond association, and breaks the oxygen bond through heating, thus gelatinization occurs.
The gelatinization process can be seen as the melting process of starch microcrystals, where the particles undergo a phase transition from ordered to disordered. This process includes complex phenomena such as water absorption and heat absorption of starch particles, swelling and hydration, disappearance of crystalline state, and rapid increase in paste degree.