Preparation and Structural Characterization of Different Starch-based Aerogels

Abstract

The micromorphology and functional properties of aerogels from rice, pea, potato or corn starch were characterized by a scanning electron microscope (SEM), an automatic surface area and pore size analyzer, an X-ray diffractometer, and a texture analyzer. The findings revealed that all the four starch aerogels had low density and high porosity. Under SEM observation, rice starch aerogel showed a lamellar structure, pea and potato starch aerogels showed a porous structure with uneven pore size distribution and thick pore walls in some zones, and corn starch aerogel presented a good three-dimensional network structure. The average pore sizes of the four starch aerogels were not much different, mainly distributed in the range of 5–13 nm, whereas there were differences in specific surface area, being smallest in pea starch aerogel (0.330 m2/g) and largest in corn starch aerogel (0.562 m2/g). The X-ray diffraction results showed that the crystallinity of these four starches declined after gelatinization and retrogradation, with corn starch experiencing the greatest decrease, from 30.71% to 8.13%. Compared with pea and potato starch aerogels, corn starch aerogel had higher solubility, water absorption rate, and Young’s modulus (6.233 MPa), and showed stronger deformation resistance, indicating excellent aerogel performance.

Keywords

• starch; aerogel; micromorphology; specific surface area; aperture; mechanical properties