7/22/2023 0 Comments Soxhlet extractor complete 300mlVarious parameters of extraction can be modified to improve extraction performance (solvent, pressure, temperature, time of extraction, etc.). It is based on the ability to perform rapid (less than 30 min) and clean extraction at high pressure and temperature. Pressurized liquid extraction (PLE) has been intensively studied as an efficient extraction technique to substitute CSE. It has several disadvantages such as long operation time requiring a minimum of hours or days, large solvent volumes involved, time and energy consuming for the concentration step by evaporation to recover the final extract, and inadequacy for thermolabile analytes. Conventional Soxhlet extraction (CSE) is the most used method for solid-liquid extraction in natural product chemistry and is a reference procedure for the extraction of fat and oil according to International Organization for Standardization (ISO standards). Whereas the last step is finished after only 15 to 30 min, extraction takes at least several hours. In general, an analytical procedure for antioxidants from plants or spices comprises two steps: Extraction (Soxhlet, maceration, percolation) followed by analysis (spectrophotometry, high performance liquid chromatography coupled or not to mass spectrometry (HPLC-MS), gas chromatography coupled or not to mass spectrometry (GC–MS)). Therefore, for each batch of plant material used for industrial extraction, an analysis has to be performed to determine the amount of available extractives. The chemical composition of the plant material may highly vary depending on the local environmental conditions, development stages, plant part, harvesting season, the technique used for drying, and the storage condition. In the field of raw material extraction, the first challenge consists of determining the potential of the plant matrix that means what can be extracted and valorized. Results demonstrate that it is a rapid, clean, and environmentally friendly extraction technique. To complete the study showing that the use of PLE is an advantageous alternative to CSE, the eco-footprint of the PLE process was evaluated. A statistical comparison of the two extraction procedure (PLE and CSE) was achieved and showed no significant difference between the two procedures in terms of RA, CA, and CO extraction. PLE was further compared to conventional Soxhlet extraction (CSE) in term of global processing time, energy used, solvent recovery, raw material used, accuracy, reproducibility, and robustness to extract quantitatively RA, CA, and CO from rosemary leaves. An experimental design was applied to identify an optimized PLE set of extraction parameters: A temperature of 183 ☌, a pressure of 130 bar, and an extraction duration of 3 min enabled recovering rosemary antioxidants. Within this objective, pressurized liquid extraction (PLE) was investigated to determine the initial composition of key antioxidants contained in rosemary leaves: Rosmarinic acid (RA), carnosic acid (CA), and carnosol (CO). Nowadays, “green analytical chemistry” challenges are to develop techniques which reduce the environmental impact not only in term of analysis but also in the sample preparation step.
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