Interactions between citrus pectin and Zn2+ or Ca2+ and associated in vitro Zn2+ bioaccessibility as affected by degree of methylesterification and blockiness

Abstract

Interactions between citrus pectin and Zn 2+ or Ca 2+ and associated in vitro Zn 2+ bioaccessibility as affected by degree of methylesterification and blockiness,

Influence of Pectin Structural Properties on Interactions with Divalent Cations and Its Associated Functionalities

“…In addition, Celus et al. (, ) established that for a given DM, the interaction between Zn 2+ , Ca 2+ , or Fe 2+ and enzymatically demethylesterified citrus pectin (higher DB abs ) was stronger than alkaline demethylesterified citrus pectin (lower DB abs ), which was based on the interaction energy estimated by modeling cation binding data (based on the Langmuir adsorption model). In other words, pectins with a comparable DM but higher DB/DB abs exhibit stronger interactions with cations, which can be explained by the formation of dimers between two pectin chains as described for pectin–cation interactions (see Section “Binding Mechanisms Between between Pectin and Divalent Cations”) (Braccini & Pérez, ; Fang et al., ).…”

“…Interactions between pectin and Cu 2+ or Pb 2+ are mainly of interest in the context of excretion of these toxic metals from the human body (Section “Role of pectin in the digestive tract”) or their removal from waste waters (Section “Other pectin functionalities”). With regard to the common food‐related cations, in general, pectin shows the highest affinity for Zn 2+ followed by Ca 2+ and Mg 2+ (Assifaoui et al., ; Celus et al., ; Dronnet et al., ; Haug & Smidsrød, ; Huynh et al., ; Renard & Jarvis, ; Schlemmer, ), although Surabhi, Williams, and Elzagheid () suggest higher affinities for Ca 2+ than Zn 2+ . In the case of Fe 2+ , which is an important cation in terms of lipid oxidation or biological functions, only scarce and contradictory information is available on its interaction with pectin.…”

“…(), and Celus et al. (, ) have determined the maximum Zn 2+ and Ca 2+ ‐binding capacity and associated interaction energy of citrus pectin samples with distinct DMs through equilibrium adsorption experiments and then modeled the results obtained based on the Langmuir adsorption model (Table ). The Langmuir adsorption model defines monolayer binding between a ligand (divalent cations) and a finite number of identical binding sites (GalA units) (Khotimchenko et al., ).…”

“…() are however expressed in other units than the results of Celus et al. (), as can be seen in Table . Given the anhydrogalacturonic acid content (%) of the pectin samples, the molecular weight of galacturonic acid (194.14 g/mol) and the molecular weight of Zn 2+ (65.38 g/mol), the maximum binding capacities (obtained by Khotimchenko et al., ) can be converted to mol Zn 2+ /mol GalA to allow comparison.…”

“…For instance, Celus et al. () reported maximum binding capacities of 0.31, 0.38, and 0.45 mol Zn 2+ /mol GalA for alkaline demethylesterified citrus pectins with DMs of 58, 36, and 20%, respectively. In line with this, results of Khotimchenko et al.…”