Porous starch materials via supercritical- and freeze-drying

The production of porous materials based on starch has been explored with supercritical drying - yielding aerogel - and freeze-drying. The two drying procedures were applied on the same gelling solution of amylomaize starch pasted at 140 °C and for two concentrations (5 and 10 wt.%). After gelation and retrogradation, water from the samples to be supercritically dried was exchanged to ethanol. The resulting starch aerogel presented high specific surface area (197 m2/g). Freeze-drying was assessed by investigating the effect of the gelation, retrogradation, freezing temperature, and sublimation pressure. The resulting starch materials were macroporous, with limited specific surface area and limited mechanical integrity. Cohesive open cell foam with pore size of ~20 µm was produced by quenching the hot starch melt in liquid nitrogen. The highest specific surface area obtained with freeze-drying was 7.7 m2/g for the hot starch melt frozen at −20 °C.

Schlagworte

freeze-drying

supercritical drying

aerogel

starch

open cell foam

cryogel

cryogelation

DDC Class

530: Physik

540: Chemie

660: Technische Chemie

More Funding Information

Nestlé Product Technology Centre York

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

gels-05-00012-v2.pdf

Size

5.72 MB

Format

Adobe PDF

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Porous starch materials via supercritical- and freeze-drying