Evaluation of the phase composition of amylose by FTIR and isothermal immersion heats

Amylose, a linear component of starch, has been shown to be directly responsible for many of starchʹs physical properties. In this study isothermal DSC assisted by FTIR spectroscopy was used to determine the phase composition of amylose under various pH conditions and while shear was used to disrupt chain–chain interactions. The analysis was based on a three-phase model consisting of crystalline (type B and single helices), amorphous, and network (physical entanglements and hydrogen bonds related) environments. Varying the pH of the water present in the samples enables the detection of the presence of the networks. Such networks, preferentially located in the amorphous phase, were found to be more reactive to chemical and probably thermal modifications. However, when chain entanglements or hydrogen bond networks are found near or in the helix of the crystalline phase, the polymer becomes more resistant to chemical and physical modification. Furthermore, it was observed that pH and shear could be used to control the morphology, orientation and phase content of amylose, which had a significant impact on the biodegradability of the treated samples.