Vacuum Microwave-assisted Extraction Research Articles

Characterization of Banana Peel Corrosion Inhibitor by Vacuum Microwave Assisted Extraction (VMAE) Method in 2% HCl Environment

Banana peel is a waste that is very abundant in Indonesia. The utilization of banana peel can be used for corrosion inhibitors. The type of environment applied in this study is an acidic environment, which is carried out in 2% HCl solution media. The purpose of this study is utilize banana waste extract obtained from the VMAE method. The extract was obtained by VMAE method at 150 watts, 300 watts and 450 watts for 10 minutes using ethanol solvent. The ratio of feed and solvent used was 1:10 (b/v). The results of the extract were subjected to phytochemical tests using Dragendroff, Wagner and Mayer reagents. After that, the extract was applied to the media for corrosion rate test and GC-MS. The results of the study showed that the lowest corrosion rate was obtained at a concentration of 1500 ppm non-aerated which was 0.7347 mmpy. While based on the GC-MS test results, terpenoid compounds and vitamin E can be detected from banana peel extract, where these two compounds are antioxidant substances that can be utilized as corrosion inhibitors.

EKSTRAKSI DAUN TEMBAKAU DAN KOPI MENGGUNAKAN METODE VACUUM MICROWAVE ASSISTED EXTRACTION DENGAN VARIASI DAYA MICROWAVE

Indonesia, which has a tropical climate can be a very high commodity of tobacco and coffee, amounting to 236.900 tons tobacco and 774.600 tons coffee in 2021. It is a very big potential for Indonesia, but the use of coffee and tobacco so far, the majority are only used as ingredients for making cigarettes and coffee for making drinks. Research on the extraction of tobacco and coffee is expected to encourage opportunities for the use of tobacco and coffee for other purposes such as corrosion inhibitors. This study aims to determine the operating conditions of the extraction and yield obtained. The method is using VMAE (Vacuum Microwave Assisted Extraction) with variations in microwave power specifically 150 W and 300 W. The solvent is methanol and the extraction time is 10 minutes. The analysis carried out is the analysis of density, yield, and GC-MS. The results of the extract using methanol as a solvent reached a density 0,902 gram/mL of tobacco sample at 150 W and 0,909 gram/mL of tobacco sample at 300 W. For coffee samples, the density at 150 W is 0,855 gram/mL and the density at 300 W is 0,862 gram/mL. The yield is higher at 150 W with a tobacco samples of 16,94% and coffee samples of 12,90%. Based on the results of the GC-MS analysis, the highest component in tobacco extract is nicotine at 150 W which is equal to 92,85% and in coffee extract is caffein at 300 W with a large of 100%.

Optimization of the Vacuum Microwave Assisted Extraction of the Natural Polyphenols and Flavonoids from the Raw Solid Waste of the Pomegranate Juice Producing Industry at Industrial Scale.

Pomegranate pomace (PP) is the solid waste produced in bulk by the pomegranate juice industry which is rich in polyphenols and flavonoids that can replace the hazardous chemical antioxidants/antimicrobials currently used in the agro-food and cosmetics sectors. In the present work, the vacuum microwave assisted extraction (VMAE) of natural antioxidants from raw pomegranate pomace was investigated and successfully optimized at an industrial scale. For the optimization of PP VMAE a novel, highly accurate response surface methodology (RSM) based on a comprehensive multi-point historical design was employed. The optimization showed that the maximum recovery of PP total polyphenols as well as total PP flavonoids were obtained at microwave power = 4961.07 W, water to pomace ratio = 29.9, extraction time = 119.53 min and microwave power = 4147.76 W, water to pomace ratio = 19.32, extraction time = 63.32 min respectively. Moreover, the optimal VMAE conditions on economic grounds were determined to be: microwave power = 2048.62 W, water to pomace ratio = 23.11, extraction time = 15.04 min and microwave power = 4008.62 W, water to pomace ratio = 18.08, extraction time = 15.29 min for PP total polyphenols and PP total flavonoids respectively. The main conclusion of this study is that the VMAE extraction can be successfully used at industrial scale to produce, in economic manner, high added value natural extracts from PP pomace.

Optimization of Vacuum Microwave-Assisted Extraction of Pomegranate Fruits Peels by the Evaluation of Extracts' Phenolic Content and Antioxidant Activity.

The global interest in the use of plant by-product extracts as functional ingredients is continuously rising due to environmental, financial and health benefits. The latest advances in extraction technology have led to the production of aqueous extracts with high bioactive properties, which do not require the use of organic solvents. The purpose of this study was to optimize the conditions applied for the extraction of pomegranate peels (PP) via a “green” industrial type of vacuum microwave-assisted aqueous extraction (VMAAE), by assessing the potential bioactivity of the extracts (in terms of phenolic content and antioxidant activity), using a response surface methodology. The extraction conditions of temperature, microwave power, time and water/PP ratio were determined by the response surface methodology, in order to yield extracts with optimal total phenolics concentrations (TPC) and high antioxidant activity, based on the IC50 value of the scavenging of the 2,2-diphenyl-1-picrylhydrazyl (DPPH●) radical. The values of the optimum extraction parameters, such as extraction temperature (61.48 and 79.158 °C), time (10 and 12.17 min), microwave power (3797.24 and 3576.47 W) and ratio of water to raw material (39.92% and 38.2%), were estimated statistically for the two responses (TPC and IC50 values), respectively. Under these optimal extraction conditions, PP extracts with high TPC ((5.542 mg Gallic Acid Equivalent (GAE)/g fresh PP))/min and radical scavenging activity (100 mg/L (1.6 L/min)) could be obtained. Our results highlighted that the optimized industrial type of VMAAE could be a promising solution for the valorization of the PP by-products.

Enhancing the recovery of cabbage glucoraphanin through the monitoring of sulforaphane content and myrosinase activity during extraction by different methods

Abstract Since endogenous hydrolysis of glucoraphanin into sulforaphane is inefficient and difficult to control, a means to effectively extract glucoraphanin from its source, so that exogenous conversion can be later performed, is desired. In this study, selected extraction methods, i.e., combined ultrasound-assisted extraction and microwave-assisted extraction (UAE + MAE), vacuum microwave-assisted extraction (VMAE), UAE + VMAE and Soxhlet extraction, with water as an extraction solvent, were employed to extract glucoraphanin from cabbage outer leaves, with the aim to enhance the extraction yield and at the same time minimize the loss of the compound. Use of fresh versus steamed leaves for the extraction was also compared. Evolutions of the cabbage-water temperature as well as glucoraphanin and sulforaphane contents of the extracts along with the myrosinase activity were monitored. UAE + VMAE led to a significantly higher content of glucoraphanin than UAE + MAE and VMAE; Soxhlet extraction resulted in a lower glucoraphanin content and required a much longer time. Nevertheless, UAE + VMAE could not rapidly inactivate myrosinase in the fresh leaves, resulting in some conversion of glucoraphanin into sulforaphane, which suffered degradation during the extraction. UAE + VMAE of steamed cabbages proved to yield the highest maximum content of glucoraphanin, with the value of 650.09 μmol/100 g dry weight, 87% higher than that obtained via the use of the fresh cabbages in combination with UAE + VMAE. Simple kinetic modeling of the extraction processes was also attempted.

Application of ionic liquids in vacuum microwave-assisted extraction followed by macroporous resin isolation of three flavonoids rutin, hyperoside and hesperidin from Sorbus tianschanica leaves

Rutin, hyperoside and hesperidin were effectively extracted from Sorbus tianschanica leaves by an ionic liquid vacuum microwave-assisted method. A series of ionic liquids with various anions and alkyl chain length of the cations were studied and the extraction was performed in [C6mim][BF4] aqueous solution. After optimization by a factorial design and response surface methodology, total extraction yield of 2.37mg/g with an error of 0.12mg/g (0.71±0.04mg/g, 1.18±0.06mg/g and 0.48±0.02 for rutin, hyperoside and hesperidin, respectively) was achieved under -0.08MPa for vacuum, 19min and 420W for microwave irradiation time and power, and 15mL/g for liquid-solid ratio. The proposed method here is more efficient and needs a shorter extraction time for rutin, hyperoside and hesperidin from S. tianschanica leaves than reference extraction techniques. In stability studies performed with standard rutin, hyperoside and hesperidin, the target analytes were stable under the optimum conditions. The proposed method had a high reproducibility and precision. In addition, separation of rutin, hyperoside and hesperidin from [C6mim][BF4] extraction solution was completed effectively by AB-8 macroporous resin adsorption and desorption process. Ionic liquid vacuum microwave-assisted extraction is a simple, rapid and efficient sample extraction technique.

Comparative evaluation of atmospheric and vacuum microwave‐assisted extraction of bioactive compounds from fresh and dried Centella asiatica L. leaves

SummaryMicrowave‐assisted extraction (MAE) involves extraction under higher‐temperature and oxygen‐rich environment, which may cause degradation of bioactive compounds being extracted. Reducing the extraction temperature by reducing the system pressure is thus of interest. Nevertheless, information is lacking on the kinetics of vacuum microwave‐assisted extraction (VMAE) at various pressures. Detailed temperature evolution of a material–solvent mixture during VMAE is also not available. This study investigated the extraction kinetics of triterpene saponins and phenolics from both fresh and dried Centella leaves during MAE and VMAE at various pressures. In the case of fresh leaves, the maximum contents of triterpene saponins were reached when VMAE was performed at 60 kPa, whereas the maximum total phenolics content (TPC) was achieved when the extraction was performed at atmospheric condition. In the case of dried leaves, the maximum triterpene saponins contents as well as TPC were achieved when extraction was performed at atmospheric condition.

Ionic liquid-based vacuum microwave-assisted extraction followed by macroporous resin enrichment for the separation of the three glycosides salicin, hyperin and rutin from Populus bark.

An effective ionic liquid vacuum microwave-assisted method was developed for extraction of the thermo- and oxygen-sensitive glycosides salicin, hyperin and rutin from Populus bark due to the strong solvating effects of ionic liquids on plant cell walls. In this study, [C4mim]BF4 solution was selected as the extracting solution for extraction of the target analytes. After optimization by single factor experiments and response surface methodology, the optimum condition parameters were achieved, which included 1.0 M [C4mim]BF4, 2 h soaking time, −0.08 MPa vacuum, 20 min microwave irradiation time, 400 W microwave irradiation power and 25 mL/g liquid/solid ratio. Under the optimum conditions, higher extraction yields of salicin (35.53 mg/g), hyperin (1.32 mg/g) and rutin (2.40 mg/g) were obtained. Compared with other extraction methods, the developed method provided higher yields of the three target components after a relatively shorter extraction time (20 min). No obvious degradation of the target analytes was observed under the optimum conditions in performed stability studies and the proposed method had a high reproducibility. Meanwhile, after adsorption and desorption on macroporous D101 resin, the target analytes can be effectively separated from the [C4mim]BF4 ionic liquid extraction solution and the yields of salicin, hyperin and rutin were 89%, 82% and 84%, respectively. The recovered [C4mim]BF4 ionic liquid presented a good extraction effect on the three analytes after recycling five times.

Microwave-assisted extraction performed in low temperature and in vacuo for the extraction of labile compounds in food samples

In this study, low temperature vacuum microwave-assisted extraction, which simultaneous performed microwave-assisted extraction (MAE) in low temperature and in vacuo environment, was proposed. The influencing parameters including solid/liquid ratio, extraction temperature, extraction time, degree of vacuum and microwave power were discussed. The predominance of low temperature vacuum microwave-assisted extraction was investigated by comparing the extraction yields of vitamin C, β-carotene, aloin A and astaxanthin in different foods with that in MAE and solvent extraction, and 5.2–243% increments were obtained. On the other hand, the chemical kinetics of vitamin C and aloin A, which composed two different steps including the extraction step of analyte transferred from matrix into solvent and the decomposition step of analyte degraded in the extraction solvent, were proposed. All of the decomposition rates ( K 2) for the selected analyte in low temperature, in vacuo and in nitrogen atmosphere decreased significantly comparing with that in conventional MAE, which are in agreement with that obtained from experiments. Consequently, the present method was successfully applied to extract labile compound from different food samples. These results showed that low temperature and/or in vacuo environment in microwave-assisted extraction system was especially important to prevent the degradation of labile components and have good potential on the extraction of labile compound in foods, pharmaceutical and natural products.

Evaluation of vacuum microwave-assisted extraction technique for the extraction of antioxidants from plant samples

In the present work, vacuum microwave-assisted extraction (VMAE) was to perform microwave-assisted extraction in vacuum. Two well-known antioxidants, vitamin C from guava and green pepper, and vitamin E (alpha-tocopherol and gamma-tocopherol) from soybean and tea leaves, which were easy to be oxidized, were chosen as representative target compounds for the evaluation of VMAE. The extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in VMAE and those in MAE performed in atmosphere (air-MAE) were compared and the effects of extraction time, extraction temperature and sample matrix were studied. Moreover, the effects of the oxygen and subpressure invacuo were also discussed via performed MAE in N(2) atmosphere (N(2)-MAE). The extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in VMAE were higher than that in air-MAE, 35% increments of vitamin C from green pepper, 22% increments of alpha-tocopherol and 47% increments of gamma-tocopherol from tea leaves were obtained, respectively. The comparable increased extraction yields of vitamin C, alpha-tocopherol and gamma-tocopherol in N(2)-MAE to that in air-MAE confirmed that oxygen in system was the crucial factor for the oxidation of vitamin C and vitamin E, VMAE was beneficial for the extraction of these oxygen-sensitive compounds. In addition, the subpressure invacuo in the VMAE system also showed positive affect on the extraction yields. On the basis of preventing oxidation and improving extraction efficiency of target compounds because of less oxygen and subpressure invacuo in the extraction system, VMAE has good potential for the extraction of oxygen-sensitive and thermosensitive compounds from plant samples.

Study of vacuum microwave-assisted extraction of polyphenolic compounds and pigment from Chinese herbs

Vacuum microwave-assisted extraction (VMAE), in which microwave-assisted extraction (MAE) was performed in vacuum, was specially designed and applied for the extraction of polyphenolic compounds and pigments from Chinese herbs. The extraction conditions including solid/liquid ratio, extraction time, extraction temperature and degree of vacuum were optimized. Subsequently, VMAE, MAE, and conventional heating reflux extraction (HRE) were evaluated with resveratrol and emodin extraction from Rhizma Polygoni Cuspidati, myricetin and quercetin extraction from Myrica rubra leaves, and safflomin A extraction from Flos Carthami. In addition, the different microstructures of those rhizome, leaf, and flower samples were investigated before and after extraction. It was obvious that the extraction yields of resveratrol, myricetin and safflomin A (thermosensitive compounds) with VMAE were higher than that with MAE or HRE by increments of 6.4–9.4% and 7.9–29.5%, respectively. In contrast, there was no obvious difference among the extraction yields for emodin and quercetin (thermo-stable compounds) with VMAE, MAE and HRE, except that the solvent consumption in VMAE was decreased. The results suggest that VMAE is a good alternative for the extraction of polyphenolic compounds and pigments, especially thermosensitive compounds, from Chinese herbs.