Polyphenols are a diverse group of naturally occurring compounds found abundantly in plants. They are characterized by multiple hydroxyl groups attached to aromatic rings and are classified into four main categories: flavonoids, phenolic acids, lignans, and stilbenes. Polyphenols are present in a wide variety of foods, including fruits, vegetables, tea, coffee, chocolate, and wine, with common examples like quercetin, resveratrol, and catechins.
Known for their antioxidant properties, polyphenols play a significant role in reducing oxidative stress and inflammation, contributing to heart health, reducing diabetes risk, and supporting immune function. Some polyphenols may also possess anticancer properties. Though they are considered beneficial for human health, certain polyphenols can act as antinutrients by inhibiting the absorption of essential minerals like iron. Their sensory properties, such as bitterness and astringency, are determined by their molecular structure and degree of polymerization.