INTEGRATED AND SUSTAINABLE STRATEGY FOR THE INVESTIGATION AND VALORIZATION OF EXTRA VIRGIN OLIVE OIL EXTRACTS AND BY- PRODUCTS

Nutrition allows to ensure the intake of energy and nutrients that guarantee growth, development, and good health. The use of foods that can promote health or delay the onset of disease are receiving a lot more attention. A group of essential components of the human diet are the bioactive molecules present in plant foods. The scientific community has given polyphenols a lot of attention due to their possible preventive effect against several complex diseases. Extra virgin olive oil (EVOO) is one naturally polyphenol-rich food that has been thoroughly researched and characterized. Apart from their antioxidant properties, they have also demonstrated a cardioprotective role, given their capacity to protect low-density lipoproteins (LDL) from oxidative stress, decrease triglycerides, and maintain normal blood levels of high-density lipoproteins (HDL) cholesterol. The promising beneficial effects of olive oil polyphenols are heavily affected by the degree of bioavailability of these molecules. Furthermore, polyphenol metabolism studies focus on the absorption of single compounds and not on assessing the behavior of a complex mixture. For example, it is known that some polyphenols present in olive oil, such as hydroxytyrosol and tyrosol, are well absorbed and metabolized leading to the formation of metabolites with different biological activities and bioavailability. Protein hydrolysates obtained from food are being used increasingly in the field of nutrition. Hydrolyzed proteins are suggested to reduce the risk that consuming proteins in their original form could trigger allergies (such as allergy to milk) and are more tolerated at the gastrointestinal level. Hydrolysates may contain bioactive peptides, which are protein fragments showing beneficial effects on human health i.e. antioxidant, hypocholesterolemic, anticoagulant, antimicrobial, hypotensive, anti-inflammatory, antitumor activity. Given the constant growth of the population and the excessive consumption of resources, the demand for low-cost proteins and peptides, obtained by considering environmental sustainability, is rapidly increasing. In addition to the population, the production of waste has grown rapidly with consequent damage to the ecosystem. Therefore, a recycling/reuse outlook is needed to allow for the decrease of the quantity of waste generated and the related socio-economic costs. The introduction of the circular economy which aims to recover materials directly from waste and by-products to re-enter then in a new production cycle could be a solution to the problem. In the Mediterranean area, olives and olive oil by-products have a substantial consequence for the environment. Olive and olive oil by-products such as pomace, leaves, stones and oil vegetation water can be fostered. Based on these considerations, the aim of my PhD thesis was to assess the antioxidant activity and intestinal trans-epithelial transport of extra virgin olive oil phenolic extract using in vitro and cellular techniques. Furthermore, a purpose of my thesis was the use of sustainable strategies that allow the valorization of by-products of the olive and oil supply chain to obtain products with high added value. To achieve this objective, the hypocholesterolemic properties of olive-vegetation water polyphenols complex was evaluated using biochemical and cellular tools. Additionally, the protein from olive seeds by-product were extracted, deeply characterized, and use to obtain protein hydrolysates by enzymatic reactions. These hydrolysates were further investigated using multidisciplinary approaches involving peptidomic techniques to profile the peptide sequences and in vitro and cellular techniques to assess their bioactivities.