Acid-thermal-induced formation of rice bran protein nano-particles: foaming properties and physicochemical characteristics

The purpose of this study was to expound on the correlation between foaming properties and physicochemical characteristics of rice bran protein (RBP) samples. RBP nano-particles (RBPNs) were prepared by acidic-thermal treatment under different RBP solution concentrations and treated times at 90 degrees C, and then the foaming properties were measured at pH 7.0 and pH 2.0. Compared to RBP, the foaming properties of RBPNs were increased at pH 7.0, and RBPNs could have better foam capacity but have no obvious changes in foam stability at pH 2.0. The results of Pearson correlation showed that the foaming properties were closely correlated with zeta potential, contact angle, and surface hydrophobicity for RBP and RBPNs, and a strong correlation between foaming capacity and surface hydrophobicity was shown for RBPNs. Additionally, the result of TEM images confirmed that RBPNs were inclined to form associated aggregates which may affect the physicochemical characteristics of RBPNs.