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Effect of pH and NaCl/CaCl 2 on the solubility and emulsifying properties of sweet potato protein
Author(s) -
Mu TaiHua,
Tan SzeSze,
Chen JingWang,
Xue YouLin
Publication year - 2008
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.3457
Subject(s) - solubility , chemistry , distilled water , emulsion , protein isolate , aqueous solution , chromatography , nuclear chemistry , food science , biochemistry , organic chemistry
BACKGROUND: The effects of NaCl and CaCl 2 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 CaCl 2 (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 CaCl 2 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 CaCl 2 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 CaCl 2 at a certain concentration could be used to improve the emulsifying properties of the protein. Copyright © 2008 Society of Chemical Industry