Generic terms ‘phenolic compounds’, ‘phenolics’ or ‘polyphenolics’ refer to more than 8,000 compounds found in the plant kingdom and possessing at least an aromatic ring with one or more hydroxyl substituents, including functional derivatives like esters, methyl ethers, glycosides, etc.
They contain benzene rings, with one or more hydroxyl substituents, and range from simple phenolic molecules to highly polymerized compounds.
Phenolic compounds mainly exist in: soluble phenolic compounds and bound phenolic compounds.
Most soluble phenolic compounds are synthesized in the intracellular endoplasmic reticulum of plants, and stored in vacuoles. Bound phenolic compounds, however, are formed by the transportation of soluble phenolic compounds to the cell wall.
Phenolic compounds possess numerous bioactive properties and, although they are not nutrients, dietary intake provides health-protective effects, therefore postharvest treatments have been used to enhance or preserve the contents of phenolic compounds in fruits and vegetables.
Plant phenolics are considered to have a key role as defense compounds when environmental stresses, such as high light, low temperatures, pathogen infection, herbivores, and nutrient deficiency, can lead to an increased production of free radicals and other oxidative species in plants.
The basic structure of a phenolic compound comprises of an aromatic ring with one or more –OH groups.
Phenolics found in food material can be divided into three major groups: simple phenols and phenolic acids, hydroxycinnamic acid derivatives and flavonoids.
Phenolic compounds
