Extraction of broad bean protein and effects of NaCl concentration and pH value on its solubility and emulsibility

Broad bean protein, with the eight essential amino acids and high levels of trace elements, is valuable for development. This work was aimed to investigate the suitability of water extraction and a method i.e ultrasonic method for extraction of broad bean protein and to study its functional properties. Broad bean protein was prepared from broad bean and the extraction rate, precipitation and functional properties of broad bean protein were investigated under the influence of variable ranges of pH value and NaCl concentration. The maximum yield of extractable protein, both by ultrasonic and water extraction methods could be achieved at the range of pH value 8-12. The isoelectric point of broad bean protein was found to be at pH 4.0-4.2. Solubility and emulsification of the protein increased, as the pH value increased from 4 to 12, with the least solubility and emulsification of protein at pH 4 and the maximum at pH 12. The solubility and emulsification of broad bean protein increased in NaCl as concentration increased from 0 to 1.0 mol/L, while further increase of NaCl concentration caused solubility and emulsification of the protein to decline both at pH 4 and pH 7. So the ultrasonic assisted extraction resulted in higher solubility and emulsification of protein than those by water extraction at the same pH value and NaCl concentration. This result with the protein extraction process and the influence of some?extracting factors lay the foundation for the development and utilization of broad bean protein.