Effect of molecular structure on emulsifying properties of sugar beet pulp pectin

To investigate the impact of each functional group on the emulsifying properties of sugar beet pulp pectin (SBPP), seven enzymes were studied in a particular order. Compositions of SBPP and enzymatically modified SBPPs were determined, and the structures of SBPPs were characterized by FT-IR. In addition, the contribution of each functional group was evaluated based on the variation in emulsion characteristics. The results showed that protein, ferulic acid-araban/galactan-protein complexes and ferulic acid played important roles in improving the surface activity, emulsifying capacity and emulsifying stability of SBPP and the extent of the decrease in the emulsifying activity followed the order: ferulic acid > ferulic acid-arabinogalactan-protein complexes > protein. The decrease of methyl ester groups mainly affected the particle sizes of the emulsion. In addition to particle sizes, the cream index of the emulsion increased with the hydrolysis of acetyl groups. Arabinose and galactose less affected emulsifying properties than other functional groups. (C) 2015 Elsevier Ltd. All rights reserved.