Effect of steam explosion treatments on the functional properties and structure of camellia (Camellia oleifera Abel.) seed cake protein

Abstract

The effect of steam explosion on the functional properties of camellia seed protein (CSP) was investigated, and the structural properties after the modified treatment were evaluated by fourier transform infrared spectroscopy (FTIR), near-UV circular dichroism (CD), thermogravimetric (TG), differential scanning calorimeter (DSC), glycosylation fluorescence, zeta potential (ζ) measurement and particle size measurement. After the steam explosion treatment, the content of simple sugars and free amino acids in the camellia seed cake (CSC) decreased, and the lightness of the CSP was reduced. The result showed that the solubility of treated CSP was significantly higher than those of untreated CSP in different pHs. The foaming and emulsifying properties of the treated CSP were higher than that of native CSP. Moreover, FTIR and DSC indicated a small change in the protein secondary structure after steam explosion, with a decrease in α-helix, random coil, β-turn contents and an increase in β-sheet content, the change of CSP tertiary structure has been confirmed by near-UV CD. In addition, steam explosion reduced the particle size and the zeta potential. Changes in protein glycosylation indicated Maillard reaction has been activated during steam explosion. These results concluded that CSP can be treated by steam explosion to modify the functional properties.