Abstract: The effects of pH value and NaCl concentration on foaming properties and foam micromorphology of rice bran protein (RBP) were investigated. The relationships between bubble characteristics and foaming properties were established. The results indicated that although the foaming capacity of RBP solution without NaCl at pH 4 was poor, the form stability was up to (88.3 ± 7.3)%. At pH 10 and 12, the foaming capacity was significantly increased to (73.3 ± 0)% and (168.9 ± 10.2)%, respectively, and the foam stability was (74.7 ± 2.5)% and (68.5 ± 2.1)%. Moreover, the foaming capacity was increased to (77.8 ± 3.8)% and (90.0 ± 5.8)% at pH 4 and 7 respectively upon the addition of 1% NaCl. The micromorphology of RBM foams indicated that initial bubble size distribution was related to foam stability at all pH levels. Changes in the foaming capacity and foam stability caused by added NaCl were related to both bubble number and average bubble area.

Key words: rice bran protein, foaming properties, foam micromorphology