Structural features and emulsifying stability of a highly branched arabinogalactan from immature peach (Prunus persica) exudates.

An acidic polysaccharide was isolated from immature peach (Prunus persica) exudates (designated as PGP). The primary structure and conformational properties were characterized by methylation and GC-MS analysis, NMR spectra, and high performance size exclusion chromatography (HPSEC) coupled with multiple detectors. Results showed that PGP was mainly consisted of arabinose (48.5%, w/w) and galactose (33.8%, w/w), with small amount of xylose (4.0%, w/w), glucuronic acid (4.3%, w/w) and galacturonic acid (2.3%, w/w) as well as trace mannose. A β-(1 → 6)-galactan backbone with branches of long α-(1 → 3)-arabinan at O -4 position of galactose, and α-(1 → 5)-Ara f at O -3 position of galactose terminated by α-Ara f and occasionally β-4-OMe-Glc p A was proposed to PGP. Conformational studies revealed that PGP presented as hyper-branched compact spherical conformation, with weight average molecular weight (Mw) of 1.40 × 104 kDa, radius of gyration (R g) of 223.4 nm, and intrinsic viscosity ([ η ]) of 2.76 dL/g in aqueous solution. High concentrations of PGP (5% and 10%, w/v) demonstrated good emulsifying stability on the O/W emulsion by inhibiting coalescence and flocculation, stabilizing the particle size, and increasing the zeta-potential of emulsion system, suggesting it could be an alternative material as emulsion stabilizer used in food industry. Image 1 • A hyper-branched β-(1. → 6)-galactan-core arabinogalactan was proposed for PGP. • PGP presented as compact spherical conformation with high Mw in aqueous solution. • High concentration of PGP showed good emulsifying stability on O/W emulsion. • The highly branched and spherical structure were the pivotal factors for its emulsifying function. [ABSTRACT FROM AUTHOR]