Superheated Steam-Mediated Multiscale Structural Reconfiguration of Starch: From Granule Architecture to Functional...

Starch is a widely used biopolymer, but native starch has several inherent limitations that restrict its industrial applications, including a broad and variable gelatinization temperature range, a strong tendency to retrograde, poor stability under shear as well as under acidic and thermal conditions, and limited freeze-thaw stability. Superheated steam (SHS) technology offers a green, physical route to mitigate these shortcomings. In the SHS process, secondary heating steam under low-humidity and oxygen-deficient conditions alters particle morphology, reduces crystallinity, and modifies chemical bond distribution through rapid heat transfer and its thermomechanical effects. Consequently, SHS typically increases the surface porosity and solubility of starch, reduces its relative crystallinity, and shifts the chain length distribution toward a higher proportion of shorter chains while decreasing the proportion of longer chains. Moreover, SHS can increase the content of resistant starch through V-type amylose-lipid complex formation at high temperatures. SHS technology reduces peak viscosity and disintegration values while enhancing final viscosity and thermal stability, thereby improving product texture and extending shelf life. Overall, quantitative control of SHS process parameters and mechanistic studies on different starch sources remain necessary for industrial conversion. SHS, as an energy-efficient and scalable physical modification technique, holds significant potential for the directional regulation of starch functionality in food applications.