New insights into the functionality of protein to the emulsifying properties of sugar beet pectin

Protein plays an important role in the emulsifying properties of sugar beet pectin (SBP). The present work was carried out to investigate the role of protein content and the combination mode between proteins and pectins on the emulsifying properties of SBP. It was found that protein contents and structural differences of SBPs affected the stability of emulsion. As the protein content increased from 0.5 to 3.0%, droplet size of emulsion stabilized by SBP decreased sharply. It turned to be stable when the protein content increased to a high level (from 3.0 to 6.0%). Thermal gravimetric analysis confirmed the structural differences among SBP samples. In order to study the functionality of protein/pectin combination mode to emulsifying properties, modification of SBP was conducted by depleting a portion of proteins, and electrostaticly or covalently binding BSA to the de-proteinized SBP. Results showed that Maillard induced conjugates exhibited the best emulsifying stability, as compared with original SBP, deproteinized SBP and the electrostatic bonding complex. These results suggested that both protein content and the combination mode between protein and pectin could affect the emulsifying properties of SBP. (C) 2016 Elsevier Ltd. All rights reserved.