Physicochemical, rheological and antioxidant properties of an arabinogalactan protein fraction from Chrysanthemum morifolium Ramat

An arabinogalactan proteins fraction (AGPF) was successfully isolated from C. morifolium. • The structural features and rheological properties of AGPF were characterized. • AGPF exhibited potential for serving as natural antioxidants in food applications. Plant-derived arabinogalactan proteins (AGPs) have attracted increasing attention due to their multifunctional bio-activities and potential applications in food, health, and biotechnology. This study provides the systematic characterization of an AGP fraction (AGPF) isolated from Chrysanthemum morifolium . The isolated AGPF was characterized as macromolecular glycoprotein complexe composed of 97.3 ± 2.8% total sugars and 1.6 ± 0.3% protein, with an apparent molecular weight of 17.5 kDa. Monosaccharide analysis revealed arabinose (Ara) and galactose (Gal) as the predominant constituents, with an Ara-to-Gal molar ratio of 2.36. Amino acid profiling showed high levels of serine, alanine, glycine, threonine, and hydroxyproline, suggesting a highly glycosylated protein backbone. Methylation and spectroscopic analyses indicated a highly branched type II arabinogalactan architecture, consisting of a β -(1 → 3)-galactan backbone substituted mainly at O -6 with arabinofuranosyl side chains. X-ray diffraction (XRD) revealed an amorphous structure, and scanning electron microscopy (SEM) showed a rough, porous morphology, consistent with their polysaccharide-rich and highly glycosylated nature. Rheological analysis demonstrated concentration-dependent shear-thinning behavior, with viscoelasticity increasing as the concentration increased from 1 to 10% ( w / v ), indicating enhanced intermolecular interactions at higher concentrations. AGPF exhibited moderate dose-dependent antioxidant activity, as demonstrated by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assays (IC 50  = 1.27 ± 0.04 mg/mL) and ferric reducing antioxidant power (FRAP) assays. Overall, these results highlight the structural features and concentration-dependent rheological behavior of an AGP fraction from C. morifolium and suggest its potential as functional hydrocolloid ingredients. Further studies in complex food systems are required to evaluate their application performance and structure–function relationships. Download: Download high-res image (394KB) Download: Download full-size image