Interactions between Pectic Compounds and Procyanidins are Influenced by Methylation Degree and Chain Length

Abstract

The interactions between procyanidins and pectic compounds are of importance in food chemistry. Procyanidins with low (9) and high (30) average degrees of polymerization (DP9 and DP30) were extracted from two cider apple varieties. Commercial apple and citrus pectins, as well as three pectin subfractions (homogalacturonans, partially methylated homogalacturonans with degree of methylation 30 and 70) at 30 mM galacturonic acid equivalent, were titrated with the two procyanidin fractions (at 30 mM (-)-epicatechin equivalent) by isothermal titration calorimetry and UV-vis spectrophotometry. Slightly stronger affinities were recorded between commercial apple or citrus pectins and procyanidins of DP30 (Ka = 1460 and 1225 M(-1) respectively, expressed per monomer units) compared to procyanidins of DP9 (Ka = 1240 and 1085 M(-1), respectively), but stoichiometry and absorbance maxima differed between apple and citrus pectins. It was proposed that methylated homogalacturonans interacted with procyanidins DP30 mainly through hydrophobic interactions. The stronger association was obtained with the longer procyanidin molecules interacting with highly methylated pectins.

Climate Influences the Content and Chemical Composition of Foliar Tannins in Green and Senesced Tissues of Quercus rubra

“…While we cannot be certain of the exact complexation of the tannins, some of them may be in association with cellulose and pectin (Le Bourvellec et al, 2009; Padayachee et al, 2012a,b; Jakobek, 2015) in the cell walls and middle lamellae. A high affinity of PCs binding to pectin has been observed (Le Bourvellec et al, 2009; Watrelot et al, 2013; Jakobek, 2015), meaning that tannins in the Wet treatment with the highest percentage of PCs and greater chain-length could have a greater complexation capacity with cell wall components. Alternatively, the greater chain-length and higher proportion of PC units would have resulted in lower extractability of tannins from the leaf tissues, resulting in the observed lower content of tannins in Wet treatments.…”

Decoupling the direct and indirect effects of climate on plant litter decomposition: Accounting for stress‐induced modifications in plant chemistry

“…In addition to their abundance, the localization of tannins can also influence tissue decomposition. For example, tannins that form complexes with the cell wall through tannin–pectin complexes (Jakobek, ; Watrelot, Le Bourvellec, Imberty, & Renard, ) may decrease the decomposition susceptibility of senesced litter compared with vacuolar tannins that are susceptible to leaching losses during early stages of decomposition (Schofield, Hagerman, & Harold, ). Thus, the decomposition susceptibility of senesced litter is often robustly correlated with the proportion of fiber‐bound tannins than with total tissue tannins.…”

Effect of maturity on the phenolic compositions of pear juice and cell wall effects on procyanidins transfer

“…Arabinogalactan had the lowest affinity for procyanidins (Watrelot, Le Bourvellec, Imberty, & Renard, 2014). Watrelot, Le Bourvellec, Imberty, and Renard (2013) showed also that the strongest association was obtained with highly polymerized procyanidins and highly methylated pectins. The adsorption mechanism involves the establishment of non-covalent interactions, hydrogen bonds and hydrophobic interactions (Le Bourvellec, Bouchet, & Renard, 2005;Le Bourvellec, Guyot, & Renard, 2004;Lea & Arnold, 1978).…”