Non-covalent interaction between procyanidins and apple cell wall material. Part III: Study on model polysaccharides

Area of Science:

• Food Chemistry
• Polymer Science
• Biochemistry

Background:

• Condensed tannins, or procyanidins, are polyphenolic compounds found in plants.
• Polysaccharides serve diverse roles in biological systems and material science.
• Understanding tannin-polysaccharide interactions is crucial for food, pharmaceutical, and material applications.

Purpose of the Study:

• To quantify the adsorption of procyanidins on different solid polysaccharide substrates.
• To investigate the influence of procyanidin polymerization degree and galloylation on adsorption.
• To determine the relationship between polysaccharide structure and procyanidin binding affinity.

Main Methods:

• Preparation of insoluble polysaccharide gels (pectin, xyloglucan) via cross-linking.
• Utilized commercially available insoluble polysaccharides (cellulose, starch).
• Quantified procyanidin adsorption using Langmuir isotherms to determine apparent affinity constants and saturation levels.

Main Results:

• Apparent affinity constants followed the order: pectin >> xyloglucan > starch > cellulose.
• Affinity increased with procyanidin molecular weight, except for cellulose.
• Pectin showed high affinity due to its gel network and hydrophobic pockets; cellulose and xyloglucan exhibited higher saturation levels, suggesting cooperative binding.

Conclusions:

• Polysaccharide structure significantly impacts procyanidin adsorption.
• Pectin's unique network structure enhances procyanidin binding affinity.
• Cellulose and xyloglucan's structures may promote cooperative binding and stacking of procyanidins.