Antioxidant Activity of Dietary Polyphenols in Food Systems

Dietary polyphenols are a diverse group of plant-derived compounds characterised by multiple phenolic rings and varying degrees of polymerisation. Widely present in fruits, vegetables, tea, coffee and agro-industrial by-products, these molecules serve dual roles in food systems: stabilising food quality by inhibiting lipid and protein oxidation, and offering potential health benefits through mitigation of oxidative stress in vivo. The antioxidant action of polyphenols arises from their capacity to donate hydrogen atoms or electrons to reactive oxygen species (ROS), chelate pro-oxidant metal ions and modulate endogenous antioxidant enzymes. Structure–activity relationships dictate their efficacy: the number and position of hydroxyl groups, degree of conjugation and glycosylation can enhance radical-scavenging potential or influence bioavailability. In food matrices, factors such as pH, temperature, processing methods and interactions with macromolecules affect polyphenol stability and release. Functional food design is increasingly exploiting synergistic combinations of flavonoids and phenolic acids to achieve targeted antioxidant capacity, while novel extraction and encapsulation technologies help preserve activity through processing and digestion. Sustainable valorisation of fruit and vegetable by-products has revealed abundant non-extractable polyphenols with under-appreciated antioxidant potential, opening routes to circular-economy applications. Advances in realistic assessment methods, ranging from chemical assays to cell-based and simulated gastrointestinal models, are refining our understanding of polyphenol behaviour in complex food and biological environments. This body of research underpins the development of functional beverages, fortified dairy products and nutraceutical formats aimed at prolonging shelf life, ensuring sensory quality and supporting human health by attenuating oxidative damage.

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Antioxidant Activity of Dietary Polyphenols in Food Systems publication trend

The graph below shows the total number of articles in antioxidant activity of dietary polyphenols in food systems across all publications each year (not limited to Nature Index journals).

Technical terms

Polyphenol: A plant-derived compound with multiple aromatic rings bearing hydroxyl groups, responsible for antioxidant properties.

Reactive oxygen species (ROS): Highly reactive molecules containing oxygen, such as peroxides and free radicals, which can damage lipids, proteins and DNA.

Ferric reducing antioxidant power (FRAP): A chemical assay that measures the ability of antioxidants to reduce ferric (Fe³⁺) to ferrous (Fe²⁺) ions.

Cellular antioxidant activity (CAA): A cell-based assay quantifying the capacity of compounds to inhibit oxidation within living cells.

Bioaccessibility: The fraction of a compound released from the food matrix during digestion and available for absorption.

References

1. Conceptual functional-by-design optimisation of the antioxidant capacity of trans-resveratrol, quercetin, and chlorogenic acid: Application in a functional tea. Food Chemistry (2023).
2. Blackcurrant press cake by-product: Increased chemical bioaccessibility and reduced antioxidant protection after in vitro simulation of gastrointestinal digestion. Food Research International (2024).
3. Bridging the gap in antioxidant activity of flavonoids: Correlating the oxidation of human plasma with chemical and cellular assays. Current Research in Food Science (2024).
4. Next-generation analytical platforms for antioxidant capacity assessment: The urge for realistic and physiologically relevant methods. Biomedicine & Pharmacotherapy (2023).
5. By-Products of Fruit and Vegetables: Antioxidant Properties of Extractable and Non-Extractable Phenolic Compounds. Antioxidants (2023).