Abstract

Pectin, a complex polysaccharide known for its gelling, thickening, and stabilizing properties, is an essential ingredient in various industries, including food, pharmaceuticals, and cosmetics. Its functional characteristics are highly dependent on its molecular structure, which can be influenced by extraction and purification methods. This study investigates the impact of different extraction and purification techniques—specifically ultrafiltration (UF) and alcohol precipitation with and without maltodextrin (MD) addition—on the structural and dynamic properties of pectin. To characterize the molecular dynamics and structural heterogeneity of pectin samples, time-domain nuclear magnetic resonance (TD-NMR) methods including solid echo (SE), double-quantum (DQ) build-up experiment, saturation-recovery (SR), and Goldman-Shen (GS) sequences were employed in combination with Fourier-Transform Infrared (FTIR) spectroscopy. The results demonstrated that the molecular composition of pectins is influenced by the choice of extraction and purification methods. MD treatments result in increased solid content and higher averaged spin–lattice relaxation times, indicative of a more rigid and densely packed structure. The addition of maltodextrin not only enhances the dry matter content but also stabilizes the pectin network through cross-linking and reduced water mobility, which is vital for achieving desired textural properties. The Goldman-Shen sequence provided insights into spin diffusion, revealing that treatments involving isopropanol (IPA) and UF modify the structural domains organization of pectin without significantly altering solid content. This suggests an enhancement in molecular order and flexibility. Correlation analysis of TDQ values with various models (Pake, Abragamian, Gaussian, Polynomial) further elucidates distinct molecular interactions and relaxation behaviors among different pectin samples. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.