The influence of PEG molecular weight on the structural changes of corn starch in a starch/PEG blend

Poly(ethylene glycol) (PEG) is a nonvolatile plasticizer used for starch gelatinization. Blends of starch and PEG at a fixed ratio of 50:50 (based on wt%) were prepared by varying the molecular weight of PEG. Interaction of the PEG and starch was investigated as a function of the PEG molecular weight via FT-IR and DSC experiment. The starch chain conformation changed when the molecular weight of PEG was less than 8,000. Additionally, a decrease of both the melting enthalpy and melting temperature was observed due to the miscibility change of the starch/PEG blend originating from the hydroxyl–hydroxyl interactions with the PEG molecular weight. Therefore, PEG with a molecular weight less than 8,000 can be effectively used for starch gelatinization.