Interactions between Polyphenols and Macromolecules: Quantification Methods and Mechanisms

Abstract

Non-covalent and covalent associations of polyphenols with food macromolecules are two of the most fundamental factors affecting the quality of polyphenol-rich food products. This review therefore describes the biochemical bases of associations between polyphenols and macromolecules, that is, proteins and polysaccharides. Our intent is to provide a level of understanding that can be used to underpin future research directions. This will help to resolve existing issues that limit organoleptic and nutritional qualities of polyphenol-rich foods and drinks. It will also allow a better understanding of the functional consequences of these interactions on food/biological systems. The methods used to study non-covalent and covalent interactions are described, and the limiting factors of each method are emphasized. The biochemical mechanisms of interaction between polyphenols and macromolecules are also described. In processed food, non-covalent polyphenol/macromolecule interactions are largely due to weak associations, and result from a combination of hydrogen bonds and hydrophobic interactions. The biochemical mechanisms for covalent interactions involve oxidation of phenolic compounds, whether enzymatically mediated or not, with the formation of o-quinones or o-semi-quinones, or the cleavage of procyanidin interflavanic bonds in acid medium with the formation of carbocations. The effects of factors such as polyphenol structure, macromolecule structure, relative concentrations of both polyphenol and macromolecule, solvent composition, ionic strength, temperature, and pH are discussed.

Soluble polysaccharides reduce binding and inhibitory activity of tea polyphenols against porcine pancreatic α-amylase

“…Indeed, the consistency in the slopes of correlations between the inhibition constants (K ic and IC 50 in Table 4 and K FQ and 1/K ic in Table 6) in the absence and presence of polysaccharides suggests that these constants were affected to a similar degree by the presence of polysaccharides, and that the inhibitory activity, inhibition kinetics and fluorescence quenching methods can be collectively and reasonably applied to characterize the effects of soluble polysaccharides on PPA inhibition by polyphenols. In previous studies, polyphenols have been reported to interact with polysaccharides through a combination of hydrogen bonds and hydrophobic interactions (Le Bourvellec & Renard, 2012;Renard, Watrelot, & Le Bourvellec, 2017). Polyphenols can bind with both a-amylase and polysaccharides (two different macromolecules) (Miao et al, 2013;Renard et al, 2017), and there is a competitive relationship between the two binding interactions (Soares et al, 2012;Soares et al, 2009).…”

The role of condensed tannins in ruminant animal production: advances, limitations and future directions

“…Experimental evidence suggests that tannins bind to proteins, forming a tannin coating of the protein through a surface adsorption mechanism and this can lead to precipitation of the tannin-protein complex (Dobreva et al, 2011). With high tannin-to-protein ratio, the protein is coated in tannin and leads to its precipitation, whereas a low tannin-to-protein ratio encourages interlinking of soluble tannin/protein complexes, promoting aggregation of the complexes (Spencer et al, 1988;Le Bourvellec and Renard, 2012) and, ultimately resulting in precipitation of the complex.…”

β‐cyclodextrin encapsulated polyphenols as effective antioxidants

“…[74] Certain quinones are subjected to 1,4-Michael addition by the amine groups of proteins resulting in protein cross linkages and the process is somewhat similar for a free thiol group. [75] Since RNase A is a basic protein and it does not have any free thiol group. Thus, protein polyphenol cross-linkage can be attributed to the covalent bond formation between the amine containing residues such as Lys of RNase A and polyphenol.…”