Rapid Solid-liquid Dynamic Extraction Research Articles

Rapid Solid-Liquid Dynamic Extraction (RSLDE): a New Rapid and Greener Method for Extracting Two Steviol Glycosides (Stevioside and Rebaudioside A) from Stevia Leaves.

Stevioside and rebaudioside A are the main diterpene 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 effective 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 20min of extraction using the NE, a quantity of rebaudioside A and stevioside equal to 1197.8 and 413.6mg/L was obtained, respectively, while for the CM, the optimum time was 90min. 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 extraction 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.

Supercritical fluid extraction of pyrethrins from pyrethrum flowers (Chrysanthemum cinerariifolium) compared to traditional maceration and cyclic pressurization extraction

In this work, a comparison between three extraction processes, including traditional maceration in n-hexane and ethyl alcohol, supercritical fluid extraction (SFE) and cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE), has been carried out for the extraction of pyrethrins, predominantly nonpolar natural compounds with insecticidal properties found in pyrethrum, an extract of certain species of chrysanthemums. Pyrethrins are often used in household insecticides and for the control of parasites on pets or livestock. Maceration is the cheapest method, but the values of the percent of extracted material compared to the weight of the dried flowers are lower. The extraction with supercritical CO2 is less efficient than the Naviglio extractor, but it has the advantage of not requiring the use of solvents. Consequently, all three techniques are valid for the extraction of compounds from pyrethrum flowers. The results obtained show that by suitably varying the parameters of the three extraction procedures, it is possible to obtain pyrethrin extracts for use in the production of low toxicity insecticides for warm-blooded animals and low pollution. In particular, extraction with supercritical CO2 presents an additional advantage; although oleoresin is a natural product, its extraction involves the use of solvents, while SFE is a highly efficient extraction process due to the use of CO2 in the supercritical phase without the use of solvents. On the other hand, the Naviglio extractor is an inexpensive technique and requires a minimum energy loss when compared to the extraction with supercritical fluids. Thus, the latter is more convenient on an industrial level but is not universally applicable. Nevertheless, the supercritical extraction can be used as a medium detergent of the oleoresin produced to avoid residues of the solvents left during the extraction process. Therefore, for demonstration purposes, for the SFE CO2 extraction process, numerical simulations have been performed, allowing for helpful results to optimize the process for further tests.

Comparison Between the Kinetics of Conventional Maceration and A Cyclic Pressurization Extraction Process for the Production of Lemon Liqueur Using A Numerical Model

AbstractThe purpose of this study was to compare two extraction processes for the production of lemon liqueur (limoncello)—the traditional maceration of lemon peels and a cyclically pressurized extraction process also known as rapid solid‐liquid dynamic extraction (RSLDE) that uses a Naviglio extractor. To evaluate the extraction efficiency of the two processes, dry matter obtained by the evaporation of the extracts was used to construct kinetics curves. The dry matter was directly proportional to the amount of the active principle (terpenes) extracted and consequently to the total concentration. Alcoholic extracts were analysed by gas chromatography (GC) to monitor the extraction kinetics for major components of the terpene fraction and for minor components of essential oils. Moreover, alcoholic extracts were analysed by UV spectrophotometry to identify the more abundant chemical species, while the organoleptic tests (i.e., a consumer test) performed on the final product (limoncello) provided an indication of the taste of the final product and revealed features undetectable with instrumental analytical techniques. To better understand the phenomenon considered, a numerical simulation was performed to evaluate and compare the matter flow of extractable compounds during the process.Practical ApplicationsThe mathematical model shown in this work is a scientific novelty because it is not reported in the previous literature. Indeed, the curves obtained from the kinetic analysis of the two solid‐liquid extraction procedures were interpolated to obtain a numerical model, which regulated the two extraction processes. Comparison between the kinetics of the extraction procedures showed that the rapid solid‐liquid dynamic extraction (RSLDE) process was 120 times faster than maceration and had a greater efficiency in a short time. Finally, a method proposed to follow the kinetics of the dilution of alcohol by water contained in the peels using the Karl Fisher titration method was important for establishing the alcoholic content of the beverage.

Laboratory Production of Lemon Liqueur (Limoncello) by Conventional Maceration and a Two-Syringe System To Illustrate Rapid Solid–Liquid Dynamic Extraction

Two experimental techniques of solid–liquid extraction are compared relating to the lab-scale production of lemon liqueur, most commonly named “limoncello”; the first is the official method of maceration for the solid–liquid extraction of analytes and is widely used to extract active ingredients from a great variety of natural products; the second is a two-syringe system based on a Naviglio extractor, which represents a new solid–liquid extractive technology called rapid solid–liquid dynamic extraction (RSLDE) that changes the philosophy of the process of solid–liquid extraction. Maceration is based on the principle of diffusion (Fick’s law) that depends mainly on temperature; in fact, to increase the speed of maceration, heating of the system is required. In the case of RSLDE, the principle is based on the generation, in the presence of an appropriate solvent, of a negative pressure gradient between the outside and the inside of the solid matrix, followed by a sudden restoration of the initial conditions of equilibrium, which induces the forced extraction of compounds not chemically bonded to the matrix; consequently, the extraction can be performed at room temperature. In the experiment described, students evaluate the efficiency of extraction by the two methods. This laboratory experiment can be used in a food science laboratory course for secondary schools and for university students.

Efficiency of conventional extraction technique compared to rapid-solid liquid dynamic extraction (RSLDE) in the preparation of bitter liquors and elixirs

Bitter liquors and elixirs are usually produced following traditional recipes, in most cases considered secret, that adopts different extraction processes and/or way of preparation. The ethanol as elective extraction solvent allows to obtain in the liquid phase most of the active compounds from different parts of the plants e.g. roots, bark, flowers, etc and the maceration is commonly used as extraction process. In this paper the traditional maceration procedure was compared to an innovative technology of rapid solid-liquid dynamic extraction (RSLDE), using the Naviglio Extractor. to obtain alcoholic extract of herbal mixtures.Three different mixtures of various parts of plants were extracted with both methods and results compared. The dry residue was considered as the main parameters to assess the quantity of the active compounds present in the extracts. The obtained data suggested that an high dry residue amount in the extract was correlated to an high concentration of active ingredients. Organoleptic tests performed on bitter liquors obtained from different extracts has been used to determine the optimum extraction time for the two different methods used. The results of this test showed that the bitters produced with RLSDE were more appreciated than bitter prepared by maceration.

Efficiency of conventional extraction technique compared to rapid-solid liquid dynamic extraction (RSLDE) in the preparation of bitter liquors and elixirs

Efficiency of conventional extraction technique compared to rapid-solid liquid dynamic extraction (RSLDE) in the preparation of bitter liquors and elixirs

Alkannin/shikonin mixture from roots of Onosma echioides (L.) L.: Extraction method study and quantification

This work reports the extraction procedures of alkannin/shikonin mixture from roots of six populations of Onosma echioides, by means of three extraction techniques: Soxhlet extraction, maceration and rapid solid-liquid dynamic extraction (RSLDE). Five solvents with different polarity (hexane, petroleum ether, chloroform, ethyl acetate, methanol) were also studied. Analysis of the extracts was performed by an HPLC-DAD (diode array detector) system. The most efficient extraction technique was Soxhlet procedure using ethyl acetate for 6 h. Studied samples of O. echioides showed an alkannin/shikonin content in the range of 0.02-0.24 mg/kg. Other naphthoquinone derivatives (deoxyalkannin/deoxyshikonin and 5,8-dihydroxy-2-(4-methyl-6-oxo-5,6-dihydro-2H-pyran-2-yl)-[1,4]naphthoquinone and arnebin-6) were found for the first time in O. echioides and characterized in the extracts using HPLC-MS apparatus equipped with an ESI ionization source.

Titanium pre-dip process increases life of zinc coatings : ( Iron Age, Vol. 153, No. 5.)

In this work, a comparison between three extraction processes, including traditional maceration in n-hexane and ethyl alcohol, supercritical fluid extraction (SFE) and cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE), has been carried out for the extraction of pyrethrins, predominantly nonpolar natural compounds with insecticidal properties found in pyrethrum, an extract of certain species of chrysanthemums. Pyrethrins are often used in household insecticides and for the control of parasites on pets or livestock. Maceration is the cheapest method, but the values of the percent of extracted material compared to the weight of the dried flowers are lower. The extraction with supercritical CO2 is less efficient than the Naviglio extractor, but it has the advantage of not requiring the use of solvents. Consequently, all three techniques are valid for the extraction of compounds from pyrethrum flowers. The results obtained show that by suitably varying the parameters of the three extraction procedures, it is possible to obtain pyrethrin extracts for use in the production of low toxicity insecticides for warm-blooded animals and low pollution. In particular, extraction with supercritical CO2 presents an additional advantage; although oleoresin is a natural product, its extraction involves the use of solvents, while SFE is a highly efficient extraction process due to the use of CO2 in the supercritical phase without the use of solvents. On the other hand, the Naviglio extractor is an inexpensive technique and requires a minimum energy loss when compared to the extraction with supercritical fluids. Thus, the latter is more convenient on an industrial level but is not universally applicable. Nevertheless, the supercritical extraction can be used as a medium detergent of the oleoresin produced to avoid residues of the solvents left during the extraction process. Therefore, for demonstration purposes, for the SFE CO2 extraction process, numerical simulations have been performed, allowing for helpful results to optimize the process for further tests.