Characterization and Bio-Accessibility Evaluation of Olive Leaf Extract-Enriched "Taralli"

Area of Science:

• Food Science
• Nutritional Biochemistry
• Plant Chemistry

Background:

• Olive leaves contain health-promoting compounds.
• By-products like olive leaves can be valorized into food ingredients.
• Taralli is a globally popular cereal-based food product.

Purpose of the Study:

• To incorporate olive leaf extract into taralli.
• To evaluate the impact of olive leaf extract on taralli's phenolic content and antioxidant capacity.
• To assess the bio-accessibility of polyphenols in olive leaf extract-enriched taralli during in vitro digestion.

Main Methods:

• Ultrasound-assisted extraction of olive leaf extract.
• Incorporation of extract into taralli, replacing white wine.
• In vitro digestion of taralli samples.
• Quantification of total phenols, flavonoids, and antioxidant capacity.
• High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD) analysis of key polyphenols (oleuropein, hydroxytyrosol, verbascoside).

Main Results:

• Olive leaf extract substitution increased total polyphenols, flavonoids, and antioxidant capacity in taralli.
• Oleuropein showed slight resistance after gastric digestion but degraded in the intestinal phase.
• Hydroxytyrosol and verbascoside were not resistant to digestion, degrading from the gastric phase onwards.

Conclusions:

• Olive leaf extract can enhance the nutritional profile of taralli.
• The bio-accessibility of major olive leaf polyphenols is limited during gastrointestinal digestion.
• Further research may be needed to improve polyphenol stability and absorption from fortified foods.