Effect of pH and NaCl/CaCl2 on the solubility and emulsifying properties of sweet potato protein

摘要

BACKGROUND: The effects of NaCl and CaCl2 on the solubility and emulsifying properties, namely emulsifying activity index (EAI) and emulsion stability index (ESI) of sweet potato proteins (SPPs) at pH 1-10, were investigated.RESULTS: At lower NaCl (0.1 mol L-1) and CaCl2 (0.05 mol L-1) concentrations, the solubility profiles of the SPPs were very similar to those in distilled water, and the lowest solubility occurred at pH 4. Increased NaCl and CaCl2 concentration resulted in lower SPP solubility in most of the pH studied (P < 0.05). At pH < 3, NaCl improved the EAI of SPP while at pH > 7 it reduced the EAI of the SPP (P < 0.05). Moreover, addition of NaCl also resulted in reduction of ESI of the SPP in most of the pH studied (P < 0.05). On the other hand, the presence of 0.2 mol L-1 CaCl2 rendered the EAI and ESI of the SPPs independent of the influence of pH.CONCLUSION: The present studies show that pH and salts modified the emulsifying properties of the SPPs, and CaCl2 at a certain concentration could be used to improve the emulsifying properties of the protein. (C) 2068 Society of Chemical Industry