Porous Starch-Based Material Prepared by Bioextrusion in the Presence of Zinc and Amylase–Magnesium Complex
2018
Xu, Enbo | Wu, Zhengzong | Long, Jie | Jiao, Aiquan | Jin, Zhengyu
A simple and sustainable preparation route for the creation of macropores in extruded starch was developed. Zinc ions were exogenously added into native corn starch, and then the Zn-modified starch was mixed with an enzyme (thermostable α-amylase)–magnesium complex as the biocatalyst prior to extrusion. The porous bioextrudates were characterized using SEM, XRD, FT-IR and water/oil absorption analyses. Results showed that the average pore numbers were increased (97 to 201 in the 160× SEM images), whereas the pore sizes (∼10–20 μm) were almost unchanged with the amylase concentration increased from 0.04 to 0.12%. The crystallinities of the porous extrudates were decreased to 7.9–10.2% compared to that of the native counterpart (21.1%), but their structures all exhibited traces of rigidification. Furthermore, the water absorption capacities were greatly increased (∼450–500%) while the oil absorption capacities were slightly increased (∼40%). Overall, it extends the preparation and the potential application of porous starch in the field of materials.
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