Structure-function characterization of fractionated sugar beet pectin

Abstract

Sugar beet pectin (SBP) has good emulsifying capacity but does not provide good stability as compared to gum arabic. It was thus fractionated using successive isopropanol increments to produce fractions (F1-F6), unique with respect to protein, ferulic acid, uronic acid, relative fluorescence intensity, particle size, ζ-potential and % degree of esterification. Unfractionated SBP was used as control. F1 and F4 were high (209±13 µg/mg alcohol insoluble solids (AIS); 93±20 µg/mg AIS) and low (77±9 µg/mg AIS; 14±6 µg/mg AIS) respectively in protein and ferulic acid. The surface hydrophobicity (S₀) was nearly 1.3 to 230 times higher in F1 than control or F4, respectively. Thus lower amount of isopropanol produced fractions with greater S₀. Medium chain triglyceride (MCT) emulsions showed lower D[4,3] values with F4 (0.67-0.93 µm) as compared to F1 (1.28-1.42 µm) and thus there was no simple relationship between protein content and emulsifying properties. The emulsions were also analyzed for rheological properties.