Utilization of supercritical CO2 as a processing aid in setting functionality of starch-based materials

Modification of native starch enables fabrication of a broad spectrum of technologically valuable products for food and non-food applications. Given the increased public concern about food safety and rigorous environmental regulations, a special attention is paid to non-thermal and organic solvent-free treatments of the starch-based materials. Supercritical carbon dioxide (scCO(2)) is considered to be an attractive processing aid for starch modification due to its unique physicochemical properties such as low viscosity, absence of surface tension, high diffusivity, tuneable density and controllable solvent strength, low critical parameters (7.38MPa, 31.1 degrees C), availability, and environmental acceptability. This is the first review on different use of scCO(2) as a processing aid in setting functionality of starch-based materials including scCO(2)-assisted gelatinization, fabrication of porous materials, impregnation, and chemical modification. In these processes, scCO(2) is used as a plasticizer, blowing agent, solvent, medium or anti-solvent to alter structural, and/or physicochemical properties of starch. The advantages of the scCO(2)-assisted processes for starch modification over the corresponding conventional techniques were discussed in detail.