Sea fennel: the natural preservative that comes from the sea
In the Mediterranean, a plant grows that has gone unnoticed for centuries, although not by everyone: sea fennel, or Crithmum maritimum. Traditionally used in pickles and coastal garnishes, this wild plant is now beginning to attract scientific attention… because of what it is often discarded: its old stems, withered leaves, and dried flowers.
Recent research published in Foods (2025) has shown that these crop residues, until now considered waste, can be converted into powerful functional ingredients with antioxidant and antimicrobial properties, useful for naturally preserving food.
What was found in the "waste"?
Researchers used two types of extraction, one with water and the other with food-grade ethanol (both considered safe), to obtain active compounds from sea fennel.
The extracts detected:
- Polyphenols (such as chlorogenic acid, quercetin, apigenin, and diosmin).
- Flavonoids, powerful natural antioxidants.
- Lutein and tocopherols (vitamin E), with benefits for visual and cellular health.
The hydroethanolic extract (water + ethanol) was the richest in these bioactive compounds, while the aqueous extract had a higher overall yield but a lower concentration of antioxidants.
Antioxidants to Extend Food Shelf Life
The extracts demonstrated a significant ability to:
- Prevent lipid oxidation (such as that which spoils oils or sausages).
- Reinforce stability against oxidative deterioration, comparable even to the synthetic antioxidant BHT.
This positions sea fennel as a potential natural preservative, useful for extending the shelf life of products without adding artificial additives.
Does it also fight bacteria?
Yes, but with nuances. The hydroethanolic extract showed antimicrobial activity against:
- Staphylococcus aureus (a bacteria common in food poisoning).
- Listeria innocua (a model for the dangerous Listeria monocytogenes).
However, it was not effective against Escherichia coli, another common bacteria. The aqueous extract, on the other hand, did not show antimicrobial activity against any of the strains tested.
This suggests that the composition of the extract and the extraction method are key to achieving effective preservative effects.
A clean and sustainable alternative
This study not only points to technological innovation, but also to a change in agricultural approach. Reusing sea fennel waste, which accounts for up to 40% of the plant:
- Reduces agricultural waste.
- Adds economic value to sustainable crops.
- Avoids the use of toxic or polluting solvents.
- Meets the consumer trend toward "clean label" products.
And it is not alone. Other halophytic plants, such as salicornia, have also been shown to contain polyphenols like quercetin and rutin, with antioxidant and anti-inflammatory properties. These species, which grow in saline environments without the need for intensive irrigation, represent a plant resource of high biotechnological value and low environmental impact.
Conclusion
Sea fennel, especially its neglected byproducts, offers a promising field of research and development for the sustainable food industry. Thanks to its richness in antioxidant and antimicrobial compounds, it can become a natural ally for preserving food, reducing chemical additives, and, at the same time, making better use of agricultural resources.
And if we add to this the potential of other coastal plants like salicornia, it is clear that coastal biodiversity could play a key role in the future of cleaner, more functional, and sustainable food.
Written by Sara Montaner. We rely on AI technology.