## 1 Introduction  
Plant bioactive compounds are defined as secondary plant metabolites capable of exerting a positive effect on animal or human health. Secondary metabolites are produced within the plants beyond the primary biosynthetic and metabolic routes of compounds [1]. These components are not needed for plant basic metabolism, can be regarded as products of biochemical \"sidetracks\" in the plant cells, and can cover important functions in living plants. Polyphenols, for example, can protect plants against free radicals generated during photosynthesis. Terpenoids may attract pollinators or seed dispersers or inhibit competing plants, whereas alkaloids usually ward off herbivore animals or insect attacks. Among the best-known bioactive compounds, polyphenols and terpen can delay or inhibit the oxidation of lipids or other biomolecules, and, thus, prevent or repair the damage of human cells caused by oxygen [2; 3]. The importance of these components has been emphasized in the last years. The ever-increasing consumer sensibility to the consumption of food with lower content of synthetic chemical products and the loss of efficacy of common preservatives, due to the development and diffusion of resistant bacteria, have led to increasing research activities regarding the extraction and the evaluation of the efficacy of natural antioxidants [4; 5]. The use of plant bioactive compounds as antioxidants in different commercial sectors, such as the pharmaceutical, food, and chemical industries, needs an appropriate and standardized extraction technique [6]. Extraction is the first step of any plant chemical component study and plays a significant and crucial role. The efficiency of conventional and non-conventional extraction methods strongly depends on the input parameters, the nature of the plant matrix, the chemistry of bioactive compounds, and the operator expertise [7; 8]. Traditional methods, like maceration, percolation, and Soxhlet, are known to have some limits such as time and solvent consumption, and decomposition of heat sensitivity bioactive compounds [8]. However, Soxhlet technique is still common in laboratories and industries being involved in a wide variety of official methods [9]. Recently, the need of enhancing the biological activity of plant extracts has led to the development of unconventional extraction methods. Among the latter, microwave assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasound assisted extraction (UAE), and rapid solid-liquid dynamic extraction (RSLDE) are the most interesting [10; 11; 12]. In UAE, the propagation of ultrasonic waves through a liquid medium damages plant wall, resulting in an improvement in solvent penetration; thus, bioactive components can be extracted in minutes. Therefore, with respect to conventional methods, UAE has the advantage of reducing the extraction process time and energy consumption retaining high efficiency [13; 14]. The RSLDE, performed by Naviglo Extractor(r), can be considered among the \"greenest\" strategies, operating at room temperature, with a minimum waste of energy and solvents. Naviglo's principle is based on generating, with a suitable solvent, a negative pressure gradient between the internal and external sides of a solid matrix containing extractable material, followed by a sudden restoration of the initial equilibrium conditions. This process induces the forced extraction of the compounds not chemically linked to the main structure of the solid [15]. Scientific literature presents several works about RSLDE comparison with other extraction techniques. However, few records of this comparison are aimed at food preservation [16; 17; 18; 19]. The present work focuses on the comparison of different conventional and unconventional extraction techniques (maceration, Soxhlet, UAE, and RSLDE), to obtain extracts suitable for food preservation.