Sugar beet pectins (SBP) were precipitated from a purified extract in a 75% v/v ethanol solution at an
initial extract pH (I-pH) ranging from 2.0 to 4.5. The effects of I-pH on pectin yield and pectin-cation
interactions were studied. No simple correlation between pectin yield and I-pH was observed. The
lowest pectin yield was obtained by precipitating the acidic pectin extract with ethanol at I-pH 4.5. Pectin
yield increased to a maximum value as I-pH decreased from 4.5 to 3.0. These results indicated that
decreased electrostatic repulsion between pectin chain segments enhanced pectin chainechain interactions,
thereby improving the precipitation effect. A decrease in pectin yield was observed as I-pH
decreased below 3.0. The cation content of various samples was measured by high-performance cationexchange
chromatography in order to determine the content of SBP-bound cations during precipitation.
Cation content and degree of cation binding were measured for pectins precipitated at I-pH 3.0, 2.5, and
2.0, and the results revealed that a decrease in pectin yield accompanied a decrease in cationepectin
interactions. These results suggest that the precipitation of SBP from an aqueous extract involves complex
interactions between cations, solvent molecules, and pectin chain segments. The larger precipitation
effect observed with divalent ions compared to monovalent ions may be due to enhanced inter-chain
interactions between pectin molecules, probably via the formation of intermolecular bonds.