Conjugation reaction with ferulic acid boosts the antioxidant property of arabinogalactan-protein and enhances its ability to form complex with β-lactoglobulin

• Published in: International journal of biological macromolecules 2021-01, Vol.167, p.587-594
• Main Authors: Mukherjee, Shuvam, Bera, Kaushik, Jana, Subrata, Pal, Saikat, Anand, Namrata, Ray, Bimalendu, Ray, Sayani
• Format: Article
• Language: English
• Subjects: Aegle - metabolism; Anti-oxidant activity; Antioxidants - chemistry; Antioxidants - pharmacology; Chemical feruloylation of arabinogalactan-protein; Chromatography, Gel; Complexation with β-lactoglobulin; Coumaric Acids - chemistry; Coumaric Acids - pharmacology; Hydrophobic and Hydrophilic Interactions; Hydrophobic microdomain formation; Lactoglobulins - metabolism; Magnetic Resonance Spectroscopy; Mucoproteins - chemistry; Plant Proteins - chemistry; Protein Binding; Spectroscopy, Fourier Transform Infrared
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.11.181

Ferulic acid was chemically grafted onto the arabinogalactan protein of Aegle marmelos fruit gum using 1,1′-carbonyldiimidazole as coupling reagent. Thus, grafted polysaccharides with different degrees of substitution were prepared and then characterized by gas chromatography/mass spectrometry, size exclusion chromatography, and ultraviolet-visible, infra-red, and nuclear magnetic resonance spectroscopic investigations. Fluorescence spectroscopic investigation showed hydrophobic microdomain formation in grafted polymers. The antioxidant activities of the derivatives, as determined by the 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl radical assay, were strong and increases with increasing the degree of feruloylation. Compared to parental arabinogalactan protein (K = 2.38 × 106 M−1), these grafted polymers bind more strongly with β-lactoglobulin (K = 11.4 × 106 M−1 and 8.19 × 106 M−1). Given that gum polysaccharides are valuable component in functional foods, synthesis of antioxidative graft polymer possessing good compatibility with β-lactoglobulin may have important implication. •Grafting of FA on AGP in different molar ratios was achieved by CDI activation.•Validation and quantification of grafting was accomplished.•Their dose-dependent antioxidant activity was guided by feruloylation degree.•They can form water-soluble complex with β-lactoglobulin more firmly than AGP.•Formation of hydrophobic clusters through intramolecular association observed.