TY - JOUR A1 - Einhorn-Stoll, U. A1 - Kastner, H. A1 - Hecht, T. A1 - Zimathies, Annett A1 - Drusch, S. T1 - Modification and physico-chemical properties of citrus pectin - Influence of enzymatic and acidic demethoxylation JF - Food hydrocolloids N2 - Aim of the present study was to investigate the effect of the method of demethoxylation on the particle structure and techno-functional properties of pectins with different degree of methoxylation and distribution of free carboxyl groups. Two groups of model pectins, one with 57% and one with 42% degree of methoxylation have been prepared from one single commercial pectin. Modifications were performed by an acidic and two enzymatic methods using fungal and plant-derived pectin methyl esterases. Thermal stability was investigated by thermal analysis and water uptake was determined by a sorption and a capillary sucking method. The enzyme-treated pectins were thermally less stable than the acid-treated. The water uptake of enzyme-treated pectins was higher than in acid-treated samples in the sorption method and lower in the capillary sucking tests. The different behaviour is explained by differences in pH during demethoxylation and a co-occurring variation in sodium content. Both parameters affected intermolecular interactions of the pectin macromolecules in solution, which resulted in differences in the particle morphology. The effect of the distribution of free carboxyl groups (statistical or block-wise) on the techno-functional properties was more pronounced in high-methoxylated pectins than in low-methoxylated pectins. KW - Pectin KW - Demethoxylation KW - PH-influence KW - Thermal stability KW - Water sorption PY - 2015 DO - https://doi.org/10.1016/j.foodhyd.2015.05.031 SN - 0268-005X VL - 51 SP - 338 EP - 345 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-33616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -