Influence of Dehydration Treatment on Intermolecular Interaction and Morphology of Pills Prepared from Proteins and Corn Starch
Résumé
Two series of partial confinement of hydrophilic and hydrophobic proteins, and corn starch were fabricated. The model system included corn starch and proteins i.e., zein, gliadin, gluten, soy protein, and rapeseed protein. The effects of different kinds of proteins and dehydration treatment on inner structure were characterized by scanning electron microscopy (SEM). Intermolecular interactions between proteins and corn starch were examined by Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Based on the solubility measurement results, almost all protein pills showed the similar solubility to the natural protein powders, resulting from the weak influence of different dehydration treatment on protein inner structure. The porous and compact morphology in the nonconfined and confined areas, respectively, were observed for both hydrophobic proteins and corresponding blend pills, which is highly dependent on the hydration rates. On the contrary, the hydrophilic proteins and corresponding blend pills had uniform and densely packed architecture both in nonconfined and confined areas. The FTIR results further confirmed that intermolecular interaction between corn starch and hydrophilic protein occurred both in confined and nonconfined areas, implying that corn starch granules dispersed into protein network to form the homogeneous morphology. No clear change of the characteristic peaks for hydrophobic protein blends when starch is added, attributing to no intermolecular interaction formed resulting in the micro-phase separation