Fractionation and physicochemical characterization of peach gum polysaccharides

One kind of Chinese peach gum was fractionated by different solvent extraction (water followed by alkaline solutions). Chemical analysis showed peach gum polysaccharides were acidic arabinogalactans, mainly composed of arabinose (∼50%), galactose (∼37%) and uronic acid (13–14%), with the molecular weight of ∼4.60 × 106 g/mol according to high performance size exclusion chromatography (HPSEC) analysis. Peach gum solution exhibited typical shear thinning flow behavior properties, K (consistency index) values increased while n (flow index) values decreased with the increasing of concentration. Dynamic sweep tests showed that moduli of peach gum solutions were highly dependent on frequency, concentration and temperature. Water extractable fraction was able to form gel network when concentration was higher than 4%. Alkaline extracted peach gum gave weaker rheological responses, such as lower viscosity at same concentration when compared to the water extractable fraction. Two alkaline extractable fractions exhibited similar intrinsic viscosities of 21.18 dl/g (0.1 M NaOH extractable, AE01) and 21.76 dl/g (0.5 M NaOH extractable, AE05), respectively, while water extractable fraction (WE) formed aggregate in water at low concentration. All fractions extracted from peach gum exudates showed better emulsion capacity and stability than gum arabic and fenugreek, which could be used in food industry to replace or partially replace gum arabic.