Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure

Ana Fernandes*, Joana Oliveira, Fátima Fonseca, Frederico Ferreira-da-Silva, Nuno Mateus, Jean Paul Vincken, Victor de Freitas

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The interaction between cyanidin-3-O-glucoside and four citrus pectic fractions was investigated using a combined molecular approach, including isothermal titration calorimetry (ITC), magnetic nuclear resonance (NMR) and UV–Visible spectrophotometry. These pectic fractions differed on their type and degree of esterification (amidated (AHG 30%), low (HG 30%) and high methyl esterified fractions (HG 70%)) and on the pattern of esterification (blockwise (HG-B 70%) vrs random (HG-R 70%)). The binding constant (Ka) and the associated thermodynamic parameters determined showed weak noncovalent interactions, particularly due to electrostatic interactions, hydrogen bonding and hydrophobic effect. The degree and the type of esterification of each pectic fractions had a significant effect on the binding constants determined by ITC and NMR experiments. The binding constants ranged from 102 to 104 M−1, with the highest Ka value observed for the interaction between cy3glc and low methylesterified fraction, followed by the amidated fraction. Pectic fractions with a higher degree of methyl esterification, resulted on lower binding affinities, with these interactions being mostly driven by hydrophobic effect compared to enthalpy. The different binding affinities could be correlated with anthocyanins colour impact, as a higher red colour intensity could be observed for a cy3glc model solution fortified with a low methylated fraction. However, this colour improvement was not observed for amidated fraction, presumably due to charge repulsive forces, lowering the stability of the flavylium cation.

Original languageEnglish
Article number105625
JournalFood Hydrocolloids
Volume102
DOIs
Publication statusPublished - May 2020

Fingerprint

Anthocyanins
Esterification
esterification
Polysaccharides
anthocyanins
polysaccharides
Calorimetry
Color
Nuclear magnetic resonance
calorimetry
titration
Titration
color
hydrogen bonding
electrostatic interactions
Citrus
Spectrophotometry
cyanidin
Hydrogen Bonding
enthalpy

Keywords

  • Anthocyanins
  • Cyanidin-3-O-Glucoside
  • ITC
  • NMR
  • Pectic polysaccharides
  • UV–Visible

Cite this

Fernandes, Ana ; Oliveira, Joana ; Fonseca, Fátima ; Ferreira-da-Silva, Frederico ; Mateus, Nuno ; Vincken, Jean Paul ; de Freitas, Victor. / Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure. In: Food Hydrocolloids. 2020 ; Vol. 102.
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title = "Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure",
abstract = "The interaction between cyanidin-3-O-glucoside and four citrus pectic fractions was investigated using a combined molecular approach, including isothermal titration calorimetry (ITC), magnetic nuclear resonance (NMR) and UV–Visible spectrophotometry. These pectic fractions differed on their type and degree of esterification (amidated (AHG 30{\%}), low (HG 30{\%}) and high methyl esterified fractions (HG 70{\%})) and on the pattern of esterification (blockwise (HG-B 70{\%}) vrs random (HG-R 70{\%})). The binding constant (Ka) and the associated thermodynamic parameters determined showed weak noncovalent interactions, particularly due to electrostatic interactions, hydrogen bonding and hydrophobic effect. The degree and the type of esterification of each pectic fractions had a significant effect on the binding constants determined by ITC and NMR experiments. The binding constants ranged from 102 to 104 M−1, with the highest Ka value observed for the interaction between cy3glc and low methylesterified fraction, followed by the amidated fraction. Pectic fractions with a higher degree of methyl esterification, resulted on lower binding affinities, with these interactions being mostly driven by hydrophobic effect compared to enthalpy. The different binding affinities could be correlated with anthocyanins colour impact, as a higher red colour intensity could be observed for a cy3glc model solution fortified with a low methylated fraction. However, this colour improvement was not observed for amidated fraction, presumably due to charge repulsive forces, lowering the stability of the flavylium cation.",
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Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure. / Fernandes, Ana; Oliveira, Joana; Fonseca, Fátima; Ferreira-da-Silva, Frederico; Mateus, Nuno; Vincken, Jean Paul; de Freitas, Victor.

In: Food Hydrocolloids, Vol. 102, 105625, 05.2020.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Molecular binding between anthocyanins and pectic polysaccharides – Unveiling the role of pectic polysaccharides structure

AU - Fernandes, Ana

AU - Oliveira, Joana

AU - Fonseca, Fátima

AU - Ferreira-da-Silva, Frederico

AU - Mateus, Nuno

AU - Vincken, Jean Paul

AU - de Freitas, Victor

PY - 2020/5

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N2 - The interaction between cyanidin-3-O-glucoside and four citrus pectic fractions was investigated using a combined molecular approach, including isothermal titration calorimetry (ITC), magnetic nuclear resonance (NMR) and UV–Visible spectrophotometry. These pectic fractions differed on their type and degree of esterification (amidated (AHG 30%), low (HG 30%) and high methyl esterified fractions (HG 70%)) and on the pattern of esterification (blockwise (HG-B 70%) vrs random (HG-R 70%)). The binding constant (Ka) and the associated thermodynamic parameters determined showed weak noncovalent interactions, particularly due to electrostatic interactions, hydrogen bonding and hydrophobic effect. The degree and the type of esterification of each pectic fractions had a significant effect on the binding constants determined by ITC and NMR experiments. The binding constants ranged from 102 to 104 M−1, with the highest Ka value observed for the interaction between cy3glc and low methylesterified fraction, followed by the amidated fraction. Pectic fractions with a higher degree of methyl esterification, resulted on lower binding affinities, with these interactions being mostly driven by hydrophobic effect compared to enthalpy. The different binding affinities could be correlated with anthocyanins colour impact, as a higher red colour intensity could be observed for a cy3glc model solution fortified with a low methylated fraction. However, this colour improvement was not observed for amidated fraction, presumably due to charge repulsive forces, lowering the stability of the flavylium cation.

AB - The interaction between cyanidin-3-O-glucoside and four citrus pectic fractions was investigated using a combined molecular approach, including isothermal titration calorimetry (ITC), magnetic nuclear resonance (NMR) and UV–Visible spectrophotometry. These pectic fractions differed on their type and degree of esterification (amidated (AHG 30%), low (HG 30%) and high methyl esterified fractions (HG 70%)) and on the pattern of esterification (blockwise (HG-B 70%) vrs random (HG-R 70%)). The binding constant (Ka) and the associated thermodynamic parameters determined showed weak noncovalent interactions, particularly due to electrostatic interactions, hydrogen bonding and hydrophobic effect. The degree and the type of esterification of each pectic fractions had a significant effect on the binding constants determined by ITC and NMR experiments. The binding constants ranged from 102 to 104 M−1, with the highest Ka value observed for the interaction between cy3glc and low methylesterified fraction, followed by the amidated fraction. Pectic fractions with a higher degree of methyl esterification, resulted on lower binding affinities, with these interactions being mostly driven by hydrophobic effect compared to enthalpy. The different binding affinities could be correlated with anthocyanins colour impact, as a higher red colour intensity could be observed for a cy3glc model solution fortified with a low methylated fraction. However, this colour improvement was not observed for amidated fraction, presumably due to charge repulsive forces, lowering the stability of the flavylium cation.

KW - Anthocyanins

KW - Cyanidin-3-O-Glucoside

KW - ITC

KW - NMR

KW - Pectic polysaccharides

KW - UV–Visible

U2 - 10.1016/j.foodhyd.2019.105625

DO - 10.1016/j.foodhyd.2019.105625

M3 - Article

VL - 102

JO - Food Hydrocolloids

JF - Food Hydrocolloids

SN - 0268-005X

M1 - 105625

ER -