Structure of the zein protein as treated with subcritical water

In the present study, we investigated the structure and selected functional properties of zein protein as treated with subcritical water. The results showed that subcritical water treatment, with different time (20-120min) and temperatures (110-170 degrees C), increased the solubility, foam capacity, and foam stability of zein protein significantly (p < 0.05). Analyses of particle size analysis, differential scanning calorimetry, circular dichroism spectra, scanning electron microscopy, and atomic force microscopy indicated that subcritical water treatment improved the thermal stability and the denaturation temperature of zein protein, as well as increased slightly in the percentage of ordered structural elements within the protein molecule. In addition, the particle size of zein protein increased and the surface became rough significantly. All these suggested that subcritical water is a potential green chemical, which could highly be used to change the structure and improve the functional properties of zein protein.