Nanocarriers for nutraceutical molecules from sustainable sources: development and characterization

More than one-third of food is wasted alongside the food chain. Despite national policies trying to reduce its production through laws, incentives, sensibilization, and education campaigns, food waste is a persistent issue with notable ethical, environmental, and economic repercussions. Polyphenols are a large class of organic compounds involved in several biological mechanisms. Many experimental studies hint toward their preventive capacity against several non-communicable illnesses, such as cardiovascular and neurodegenerative diseases, cancer, diabetes, and osteoporosis, fueling the great interest in this topic. Abundant in fruits and vegetables, these bioactives can also be found in food waste, which may represent a precious and exploitable source. Red cabbage (Brassica oleracea L. var. Capitata f. rubra) is a cruciferous vegetable known for its bright color and nutritional value. An abundant part of this plant, mainly composed of slightly damaged leaves and stems, is often discarded, even if still valid from a nutraceutical point of view. The water-soluble pigments in this food and in its by-product, known as anthocyanins, can be used as a natural dye, health promotor, and food sensor against spoilage. Similarly, the olive oil production chain offers notable sources of valorisable food waste. Extra-virgin Olive Oil is considered one of the main promoters of the many health benefits of the Mediterranean Diet. Its nutritional profile is characterized by an elevated concentration of monounsaturated fatty acids but also by a minor heterogeneous component containing several polar phenolic compounds, particularly hydroxytyrosol, tyrosol, and oleuropein, which have been considered by the European Food Safety Authority, capable of preventing blood lipid oxidation. However, not many olive oils can grant such a high content of phenols. The most significant part of these hydrophilic molecules (> 98%) remains in the by-product, i.e., the olive mill waste. From a circular economy perspective, many food by-products could be valorized through polyphenol extraction, stabilization, and employment. However, despite many experimental studies imputing preventive capacities to these molecules against several diseases, they are inherently fragile and challenging to be extracted from their matrices, hampering their industrial employment. In this scenario, nanoencapsulation can aid in tackling several problems, such as protecting these molecules against degradation or boosting viability and functionality, offering a semi-finished product exploitable to enhance foods and feeds. This project, conducted in collaboration with the company ECSIN EcamRicert SRL led by the expertise of Dr. Federico Benetti acting as industrial co-supervisor, aimed to develop and characterize nanoencapsulation approaches tailored for food application. In compliance with the principles of green chemistry and circular economy, model payloads, i.e., polyphenols-rich extracts prepared from red cabbage wasted leaves and olive pomace, were studied, characterized, and encapsulated into nanoparticles prepared with two different approaches: complex coacervation and ionotropic gelation, using, at the best of our possibilities, green procedures and food-grade waste-valorized wall materials. After a brief introduction in which the food waste problem is discussed and the legal framework surrounding novel food and encapsulation regulations is defined, the encapsulation process, the bioactives of interest, the encapsulation matrices used in this project, and the procedures attempted throughout the doctoral program will be thoroughly discussed.