Fractionation and physicochemical characterization of peach gum polysaccharides

Crude Chinese peach tree gum exudates were fractioned by water extraction at 80 °C, followed by alkaline extraction with 0.1 M and 0.5 M NaOH to give 3 fractions (WE, AE01 and AE05 respectively). All fractions exhibited acidic arabinogalactans structures and homogenous HPSEC profile with molecular weight of 4.60 ± 0.37 × 106 g/mol. According to rheological tests, peach gum polysaccharides exhibited typical shear thinning flow behavior properties, the moduli of gum solutions were highly dependent on frequency, concentration and temperature. Water extractable fraction was more likely to form weak gel structure than alkaline fractions when concentration was higher than 4%; alkaline extraction led to the weaker rheological response. Two alkaline extractable fractions exhibited similar intrinsic viscosities while water extractable fraction aggregate at low concentration. Peach gum polysaccharide exhibited better emulsification properties than gum arabic and fenugreek; it could be used as surfactant in food industry especially for gum arabic substitution.