###### Abstract
According to the literature, the main extraction techniques still involve the use of some sort of solvent, but the promotion of sustainable chemistry by government authorities all over the world is incentivizing the development of more environmentally friendly techniques, which are being increasingly employed nowadays [19]. Examples of these latter are supercritical fluid, ultrasound-assisted, subcritical water, and microwave-assisted extractions, along with the use of enzymes [20]. In this review, we aim at summarizing the most recent findings on the sustainable extraction of nutrients and bioactive compounds from some byproducts and wastes produced by the agri-food chain of Northeast Italy. Among these, some have been widely considered for their relevant content in bioactive metabolites, such as red fruits and grape (_Vitis vinifera_) pomace. These latter are particularly relevant: Italy leads wine production in the world, with an estimated production of 49.8 mhl of wine in 2022. This large-scale supply leads to a large-scale generation of grape pomace. Approximately 75% of produced grapes is intended for wine production, of which 20-30% represents waste products [21]. It has been estimated that the production of 1000 m\({}^{3}\) of wine generates 82.5 tons of grape pomace on a dry basis [22]. To note, northeastern regions of Italy are among the largest wine producers of the country, and this supply chain is responsible for producing more than 200,000 tons/year of byproducts comprising pomace and stalks [23]. Other byproducts, such as the residues of honey and fresh chicory production, have been less studied up to now, despite their potential content in several compounds of interest. In particular, the leafy chicory named \"radicchio\" (_Cichorium thybus_ var. _foliosum_) is a typical product of Northeast Italy that assumes an important role at both a local and national level, as it characterizes a high proportion of the agricultural income of suited areas [24]. Commercial production of colored radicchio varieties involves a laborious procedure that includes the removal of many outer leaves from heads, with the aim of keeping the inner tissues that are better developed and characteristic of the product. This procedure generates large amounts (estimated annual production in in Northeast Italy: \(>\)100,000 tons) of byproducts rich in fibers and phenolic compounds [25]. Extraction of Phytochemicals and Volatile Compounds from Agri-Food Byproducts: An Overview of Traditional Techniques and Novel Sustainable Approaches  
Several extraction procedures have been developed since ancient times, and these have been adapted to the characteristics of the matrices to extract and to the physicochemical properties of the compounds of interest. In this first part of the review, the main techniques used for the extraction of natural compounds with potential application as bioactive ingredients for food, nutraceutical, and cosmetic use will be introduced. To better understand the advantages and disadvantages of both traditional and novel approaches, a summary of the traditional extractive techniques will be presented first, and then the more innovative and sustainable methods will be discussed. The traditional techniques involve mainly extraction with solvents and include blending, solid-liquid extraction, Soxhet extraction, and sonication [26]. The main advantages and disadvantages of these techniques are summarized in Table 1.