Research and innovation network on food and nutrition sustainability, safety and security – Working ON Foods

The project proposal aims to valorize by-products of the olive oil supply chain, such as spent pomace and olive leaves, in order to produce innovative foods and products with high health potential. The primary objective involves optimizing the extraction of bittering compounds from olive leaves and spent pomace to create an enriched olive oil that is more functional and stable over time, and a dietary supplement with high antioxidant potential for blood sugar and body weight control. The optimization of the extraction process will be carried out using the Response Surface Methodology (RSM) in order to determine the optimal extraction conditions and generate an optimized extract with the highest content of phenolic compounds, mainly oleuropein (OLE), tyrosol (TYR) and hydroxytyrosol (HT), and with the highest antioxidant activity evaluated using spectrophotometric tests (TPC, DPPH, FRAP). Phytochemical analysis will be performed by HPLC-DAD and/or MS chromatography.

The optimized extracts will be added in different concentrations (such as, in combination and incorporated within liposomes) to olive oil to obtain a stable food with high nutritional value. To evaluate the stability of the oil and understand the right concentration of optimized extract and liposomes to add, various parameters will be examined, including peroxide value, acidity value, specific extinction values at 232 and 270 nm and fatty acid composition, as well as increased levels of OLE, HT and TYR.

The optimized extract will also be used to develop a new dietary supplement product for blood glucose and body weight control thanks to the presence of bittering metabolites such as OLE, TYR and HT. Several preclinical and clinical studies have indeed demonstrated the ability of bitter secondary metabolites to stimulate the secretion of gastrointestinal hormones and slow gastric emptying through interaction with bitter receptors (T2Rs) expressed at the gastrointestinal level. These activities will be investigated by in vitro studies on intestinal cell lines (STC-1) and in silico studies aimed at understanding the interaction modes of OLE, TYR and HT with T2Rs (e.g. T2R46 and T2R38).

To date this constitutes the first study regarding the potential ability of OLE, TYR and HT to activate T2Rs and by means of them to exert an antiobesogenic activity and hypoglycemic due to increased secretion of anorexigenic hormones.

The entire process, from the extraction of by-products to the production of finished product prototypes, will be carried out ensuring their safety thanks to the implementation of tests to evaluate microbial contamination of the starting plant material and toxicity tests on cellular models.

In conclusion, the project aims to produce foods and dietary supplements rich in specialized metabolites that are beneficial to human health and stable over time, offering the food and pharmaceutical industries the opportunity to offer new healthy products in line with the needs of increasingly health-conscious consumers. The entire project will be conducted following protocols in line with the concept of circular economy and green chemistry, allowing new life to be given to by-products of the olive oil industry, spent pomace and olive leaves, which, if inadequately disposed of, would lead to environmental pollution.

WP1 Coordination and management of the UNIBAS-DIS project
Oleifici Masturzo SRL
Sveba SRL

WP2 Contamination assessment and optimization of UNIBAS-DIS extraction processes
Oleifici Masturzo SRL

WP3 Application of extraction parameters on pilot scale and formulation of UNIBAS-DIS liposomes
Sveba SRL

WP4 Production of enriched oils, stability tests and UNIBAS-DIS sensory analysis
Oleifici Masturzo SRL

WP7 Production of biocompost and biomaterials and life cycle assessment (LCA) UNIBAS-DIS

WP8 UNIBAS-DIS disclosure
Oleifici Masturzo SRL
Sveba SRL

Executive summary of key findings

Optimized extraction processes (WP2): defined “optimal” operating parameters for extraction from leaves and pomace, obtaining 4 extracts (FO, FOM, S, SM) and demonstrating that:

FO (maltodextrine-free leaves) is the sample with the highest phenolic richness and antioxidant activity.

The addition of maltodextrins systematically reduces the “potency per gram” (dilution/microencapsulation effect), which is more marked in the leaves.

Antioxidant activity (WP2): With TPC, FRAP, DPPH, ABTS assays a clear general hierarchy is observed: FO > (FOM/S) > SM, with test-dependent differences.

Phytochemical profile (WP2): LC-MS/MS highlights profiles rich in secoiridoids and phenols (e.g. oleuropein/derivatives, oleoside, hydroxytyrosol, salidroside, verbascoside, flavonoids). The pomace maintains a significant share of recoverable bioactives (by-product valorization).

Enzymatic antidiabetic activity (WP2): No detectable inhibition of α-amylase and α-glucosidase → action on glucose metabolism (if present) could involve other pathways.

Gastro-protected liposomes (WP3):

Liposomes ~74 nm (uncoated) → ~100–105 nm after coating with Eudragit® L100.

Positive (+7/+8 mV) to negative (~-17 mV) zeta potential after coating (confirmation of polymer adsorption).

In antioxidant assays, liposomes with extract show increased activity compared to the free extract (e.g. DPPH 93% vs 52%).

Cellular studies (WP3):

No cytotoxicity at the concentrations tested (leaves: 10–0.1 μg/mL; pomace: 100–1 μg/mL).

Leaves: ROS reduction in hyperglycemia; liposomes more effective up to lower doses; glucose uptake reduction; modulation of GLP-1 secretion (interpreted as homeostatic restoration).

Sansa: GLP-1 increase (more marked with liposomes) and intracellular Ca²⁺ increase consistent with GLP-1 secretion.

Enriched EVO oils (WP4): All enriched formulations improve oxidative stability; 1% is the best concentration; Mix leaves+pomace 1% performs best on oxidative markers and maintains a sensory “harmonic” profile.

OLEACTIVA supplements (WP5): developed 12 formulas, produced in pilot 4 references (capsules, tablets, stickpack, liquid). Good T0 data on oleuropein and microbiology; criticality highlighted: compressed disintegration test failed (0/6).

Waste valorization and LCA (WP7): use of exhausted matrices for breeding Hermetia illucens with promising preliminary results (highest performing sansa). LCA shows that enhancing pomace reduces the impacts attributed to oil; in particular Climate change: −83.30% in the energy allocation scenario (0.33511 → 0.05596 kg CO₂ eq).

Disclosure (WP8): Posters, oral presentations, scientific articles and final event (27/10/2025).