Reactions of Plant Phenolics with Food Proteins and Enzymes under Special Consideration of Covalent Bonds

Abstract

Secondary plant metabolites are important native food components, which are becoming more and more interesting due to their physiological effects on human beings. One of the largest groups of these compounds is represented by plant phenols. This review summarizes the structure, classification and distribution of the phenolic compounds in plant foods, their chemistry and signification with regard to food processing and -storage as well as their physiological effects. This work focuses mainly on such reactions of the phenolic substances with proteins and enzymes that lead to covalent bonds. The derivatives formed have been characterized in terms of changes in their physicochemical and structural properties. The effect on the proteolytic in vitro digestion has been also illustrated. Further aspects reported include the influence on enzyme activity and -kinetic parameters. The different aspects of the nutritional-physiological consequences of such reactions in food and body, especially considering their significance to food science and technology are discussed.

Plant polyphenols in cell-cell interaction and communication

“…For details see reviews. 8,12 Figure 2. Tannin (A) and a fragment of polymeric chain of gallate rich black tea pigment (B).…”

“…1) in presence of peroxidases, polyphenol oxidases, alkaline pH, or transition metals they could be involved in reactions with free nucleophilic functional groups such as sulfhydryl, amine, amide, indole and imidazole substituents; 11 and result in covalent binding with different residues including lysine, methionine, cysteine and tryptophane. 8,12 We expect that terminal amino groups of phosphatidylethanolamines or sulfolipids of biological membranes can also participate in covalent binding with quinones. The consequence of chemical derivatization of proteins may lead to changes in α-helix and random coiled constituents and be accompanied by modulation of protein physical properties and functioning.…”

“…[6][7][8][9] The polyphenolic compounds are generally not very active chemically and only electrostatic and hydrophobic forces are responsible for their interaction within cells. However, after oxidation of catechol and gallate 10 moieties to quinones ( Fig.…”

“…The consequence of chemical derivatization of proteins may lead to changes in α-helix and random coiled constituents and be accompanied by modulation of protein physical properties and functioning. 8 Among the polyphenolic compounds, tannins express the strongest influence on the lipid bilayer properties. The influence depends on the presence of numerous gallic moieties in the tannin molecule.…”

Digestion susceptibility of seed globulins isolated from different lupin species

“…Firstly, phenolic compounds cause changes in the physicochemical properties of proteins. The formation of such complexes may lead to lowering the nutritional value of proteins by changing of their solubility, thermal stability and digestibility [40,41]. Secondly, the fact of proteins complexes formation may substantially reduce the health-promoting potential of phenolic compounds by masking of their antioxidant properties [41,42].…”