Tailoring structural, rheological and gelling properties of watermelon rind pectin by enzymatic treatments

In this work, pectin extracts from watermelon rind (WRP) were enzymatically treated to evaluate their potential for preparing hydrogels with the addition of CaCl 2 . Based on a previous two different conditions selected obtain WRP according 1) highest yield (OP) or 2) without negatively affecting branching and native structure (OPA). Firstly, both modified using treatments (de-esterification and/or de-branching galacturonic arabinose side chains, deproteinization), impact esterification degree, monosaccharide composition changes structural properties (linearity degree) deeply analysed. Then, effect resulting rheological behaviour nanostructure was investigated. The presence long branched chains high methyl-esterified acid promoted formation weaker whereas de-esterification original enabled intermolecular association giving rise stronger ordered densely packed structures (as deduced SAXS results). However, small arabinogalactans in de-branched de-esterified acted as reinforcement agents, inducing more networks than less-branched counterpart. These results demonstrated hydrogel-forming capacity. • Two modified. Enzymes acting neutral sugar did not significantly de-branch structure. Weaker gels obtained when pectins enzymes. Stronger produced de-esterified. strongest enzymes combined.