Characterization of Water-soluble Pectic Polysaccharides in Peach (Prunus persica (L.) Batsch) Fruit

Abstract

Water soluble pectin in peach (Prunus persica (L.) Batsch) fruit, which is well known to increase with fruit maturation, was isolated and characterized. The water soluble polysaccharides were extracted from crude cell walls of immature and over-ripe fruits and separated on an ion exchange column (DEAE-Agarose 2.5 × 30 cm). By eluting with 50 mM phosphate buffer (pH 6.0) and then the buffer containing 0.1 and 0.5 M NaCl, the water soluble polysaccharides from unripe and ripe fruits were separated into fraction I and II, and fractions I, II and III, respectively. The polysaccharides in fractions II and III (pectic polymers) were applied to the gel filtration column (Sepharose CL-4B 1.5 × 40 cm) to determine their molecular weights. The data reveal that the molecular weight of fraction III was heavier than that of II. The sugar composition analysis, using gas liquid chromatography, indicated that the two dominant neutral sugars in fraction II were galactose (30-40%) and arabinose (40-48%), whereas in fraction III, it was arabinose (more than 65%). These data show that fractions II and III have different neutral side chains of pectic polysaccharides.