ORIGINAL PAPER Rapid Solid-Liquid Dynamic Extraction (RSLDE): a New Rapid and Greener Method for Extracting Two Steviol Glycosides (Stevioside and Rebaudioside A) from Stevia Leaves Monica Gallo 1 & Manuela Vitulano 2 & Anna Andolfi 2 & Marina DellaGreca 2 & Esterina Conte 2 & Martina Ciaravolo 2 & Daniele Naviglio 2 # Springer Science+Business Media New York 2017 Abstract Stevioside and rebaudioside A are the main diter- pene glycosides present in the leaves of the Stevia rebaudiana plant, which is used in the production of foods and low-calorie beverages. The difficulties associated with their extraction and purification are currently a problem for the food processing industries. The objective of this study was to develop an ef- fective and economically viable method to obtain a high- quality product while trying to overcome the disadvantages derived from the conventional transformation processes. For this reason, extractions were carried out using a conventional maceration (CM) and a cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE) by the Naviglio extractor (NE). After only 20 min of extraction using the NE, a quantity of rebaudioside A and stevioside equal to 1197.8 and 413.6 mg/L was obtained, respectively, while for the CM, the optimum time was 90 min. From the results, it can be stated that the extraction process by NE and its subsequent purification developed in this study is a simple, economical, environmentally friendly method for producing steviol glycosides. Therefore, this method constitutes a valid alternative to conventional extraction by reducing the extrac- tion time and the consumption of toxic solvents and favouring the use of the extracted metabolites as food additives and/or nutraceuticals. As an added value and of local interest, the experiment was carried out on stevia leaves from the Benevento area (Italy), where a high content of rebaudioside A was observed, which exhibits a sweet taste compared to stevioside, which has a significant bitter aftertaste. Keywords Steviol glycosides . Extraction . Maceration . RSLDE . Food additives . Nutraceuticals Introduction Stevia, scientifically known as Stevia rebaudiana Bertoni, is a perennial plant native to the Rio Monday Valley in the high- lands of Paraguay. This plant possesses an extraordinary sweetening power thanks to the presence of diterpene glyco- sides, known as steviol glycosides, which have a sweetness capacity approximately 200–300 times greater than that of sucrose but has zero calories. The main components of steviol glycosides are stevioside and rebaudioside A, which represent a viable alternative to sugar and other artificial sweeteners [1, 2]. The total amount of steviol glycosides obtainable from the Stevia leaves is generally 8 to 10% of the dry weight. Percentages vary according to cultivar, cultivation methods and other extrinsic factors such as the composition of the soil, weather conditions, and irrigation, among others [3]. In partic- ular, stevioside and rebaudioside A are more than 70% of the mixture of steviol glycosides present in the leaf, and in almost all varieties, stevioside is the main component [4, 5]. Typical proportions on a dry weight basis for the four major glycosides found in the leaves of wild Stevia plants are 0.3% dulcoside, 0.6% rebaudioside C, 3.8% rebaudioside A and 9.1% stevioside [6]. The sweetener properties of these glycosides differ from each other. Stevioside is between 110 and 270 times sweeter than sucrose, rebaudioside A is between 150 and 320 times sweeter, rebaudioside C is 40 to 60 times sweeter, and dulcoside A is 30 times sweeter than sucrose * Monica Gallo mongallo@unina.it 1 Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, via Pansini, 5, 80131 Naples, Italy 2 Department of Chemical Sciences, University of Naples Federico II, via Cintia, 80126 Naples, Italy Plant Foods Hum Nutr DOI 10.1007/s11130-017-0598-1