Bio-based sweet potato starch cryogels: Linking hydrogel rheological properties to cryogel structure-functionalities

Area of Science:

• Materials Science
• Biomaterials Engineering
• Sustainable Chemistry

Background:

• Starch-based cryogels offer biodegradable and tunable solutions for environmental and industrial needs.
• Sweet potato starch is an abundant, low-cost, and underutilized resource with economic and sustainability advantages.

Purpose of the Study:

• To develop novel starch-based cryogels using sweet potato as a sustainable starch source.
• To investigate the impact of starch concentration and gelatinization degree on cryogel properties.
• To correlate hydrogel rheology with the structural, mechanical, and thermal characteristics of the resulting cryogels.

Main Methods:

• Preparation of starch-based cryogels from sweet potato starch.
• Rheological analysis of hydrogels.
• Characterization of cryogel structure, mechanical strength, and thermal properties using techniques like DSC.
• Evaluation of water and oil absorption capacities.
• Measurement of thermal conductivity.

Main Results:

• Higher starch concentrations led to more elastic hydrogels, lower gelation temperatures, and improved cryogel integrity, resulting in stronger, less deformable cryogels.
• Optimized gelatinization times (7 and 15 min) produced denser cryogel networks with smaller, continuous pores.
• Sweet potato starch exhibited rapid gelatinization (86% at 90°C/15 min).
• Water absorption increased with starch concentration and gelatinization time (up to 9.79 g/g), while oil absorption was higher at lower starch concentrations (19 g/g).
• Low thermal conductivity (0.035-0.037 W/m·K) indicated good insulation properties.

Conclusions:

• Sweet potato starch-based cryogels offer a sustainable and functional alternative to conventional materials.
• The developed cryogels demonstrate potential for applications in the food, nutraceutical, and packaging industries.
• Tunable properties achieved through controlled starch concentration and gelatinization present opportunities for material design.