The heteropolysaccharide of Mangifera indica fruit: Isolation, chemical profile, complexation with β-lactoglobulin and antioxidant activity

A 91 kDa heteropolysaccharide (F2) was isolated from Mangifera indica fruit via extraction with H₂O, purification by C₂H₅OH, starch removal and ion exchange chromatography. This polymer was made up mostly of Ara, Gal, Glc, Rha, Xyl, and GalA in a 37: 29: 9:3:2:19 molar proportion. It inherited a small backbone containing GalpA and Rhap units substituted with very large side chains containing differently linked Ara and Gal units plus esterified gallic acid (GA) residue. Several enzymes generated oligosaccharides including (i) Ara_2-10Ac_6-22, (ii) Gal_1-8Ac_5-26 and (iii) GA₁Gal₁Ac₇ were characterized. This polysaccharide, which showed dose dependent antioxidant activity, exhibited synergism with gallic acid, and formed a complex (K = 1.2 × 10⁶ M^-1) with β-lactoglobulin. Accordingly, H₂O treatment produces a polysaccharide with desired biochemical properties; this could be effective in designing innovative functional food with flexible makeup.

Keywords: Antioxidant activity; Complexation with β-lactoglobulin; Isolation and characterisation; Mangifera indica fruit heteropolysaccharide.