Tailoring the morphology and properties of starch aerogels and cryogels via starch source and process parameter

Porous starch materials with various morphology and properties were made via starch dissolution, retrogradation and drying either with supercritical CO2 (aerogels) or lyophilisation (cryogels). Their properties were correlated with the rheological response of retrograded starch gels and crystallinity of aerogels and cryogels. All starch cryogels possess very low density (0.07 - 0.16 g/cm(3)), very large macropores and low specific surface area (around 3-13 m(2)/g). Their morphology is mainly the replica of sublimated ice crystals. The properties of starch aerogels strongly depend on starch source: the lowest density (around 0.1 g/cm(3)) and highest specific surface area (170-250 m(2)/g) was recorded for pea starch aerogels and the highest density (0.3-0.6 g/cm(3)) and lowest specific surface area (7-90 m(2)/g) for waxy maize starch aerogels. The morphology and properties of starch aerogels are interpreted by amylose and amylopectin evolution during retrogradation.

Automated summary

Porous starch materials were prepared via starch dissolution, retrogradation, and drying with supercritical CO2 or lyophilisation, with properties correlating to the rheological response of starch gels and crystallinity of aerogels and cryogels. Starch cryogels exhibited low density, large macropores, and low specific surface area, resembling sublimated ice crystals, while starch aerogels showed varied properties depending on starch source, with pea starch aerogels having the lowest density and highest specific surface area. The morphology and properties of starch aerogels are explained by the evolution of amylose and amylopectin during retrogradation.