Microwave-assisted Extraction Method Research Articles

Optimization of a Microwave-Assisted Extraction Method for the Recovery of the Anthocyanins from Jabuticaba By-Products

In this study, a Box-Behnken Design (BBD) has been used to optimize the recovery of bioactive compounds from jabuticaba (Myrciaria cauliflora) by-products through microwave-assisted extraction (MAE). Thus, the Box-Behnken (BBD) experimental design was followed by a response surface methodology (RSM) that would allow investigating the influence of the four independent variables (temperature, solvent composition, pH, and sample-solvent ratio) that have been considered. The results revealed that temperature and solvent composition (%MeOH) were the most significant factors regarding the yields of anthocyanins obtained from the studied plant matrix. The established optimized conditions and 10-min-extraction time resulted in yields of 9.70 ± 0.28 mg g−1 of total anthocyanins. The method exhibited good repeatability and intermediate precision, with RSD variations lower than 5% for both parameters. The developed process was also able to extract and identify anthocyanins in commercial samples (jabuticaba pulp and jam). The results obtained from the optimized MAE method suggest that this technique is not only efficient for the recovery of anthocyanins from jabuticaba by-products, but it is also beneficial for a circular economy approach.

Green Extraction Techniques for the Determination of Active Ingredients in Tea: Current State, Challenges, and Future Perspectives

In recent years, the scientific community has turned its attention to the further study and application of green chemistry as well as to sustainable development in reducing the consumption of raw materials, solvents, and energy. The application of green chemistry aims to ensure the protection of the environment and to also, consequently, improve the quality of human life. It offers several benefits, both socially and economically. In the last few decades, new alternative non-conventional green extraction methodologies have been developed for the purposes of the extraction of active ingredient compounds from various raw products. The main objective of this literature review is to present the current knowledge and future perspectives regarding the green extraction of tea species in respect of the isolation of safe active biomolecules, which can be used as commercially available products—both as dietary supplements and pharmaceutical formulations. More specifically, in this literature review, the intention is to investigate several different extraction techniques, such as ultrasonic-assisted extraction, ultrasonic-assisted extraction with DESs, the microwave assisted-extraction method, and the reflux method. These are presented in respect of their role in the isolation of bioactive molecules regarding different tea species. Furthermore, following the literature review conducted in this study, the commonly used green extraction methods were found to be the ultrasound-assisted method and the microwave-assisted method. In addition to these, the use of a green solvent, in regard to its role in the maximum extraction yield of active ingredients in various species of tea, was emphasized. Catechins, alkaloids (such as caffeine), gallic acid, and flavonoids were the main extracted bioactive molecules that were isolated from the several tea species. From this literature review, it can be demonstrated that green tea has been widely studied at a rate of 52% in respect of the included research studies, followed by black tea at 26%, as well as white tea and oolong tea at 11% each. Regarding the determination of the bioactive molecules, the most utilized analytical method was found in the combination of high-performance liquid chromatography (HPLC) with a photodiode array detector (PDA) and mass spectrophotometry (MS) at a usage rate of about 80%. This method was followed by the utilization of UPLC and GC at 12% and 8%, respectively. In the future, it will be necessary to study the combination of green extraction techniques with other industry strategies, such as an encapsulation at the micro and nano scale, for the purposes of preparing stable final products with antioxidant properties where, finally, they can be safely consumed by humans.

STUDY ON THE OPTIMIZATION OF MULBERRY LEAF EXTRACT BY MACERATING ETHANOL AND MICROWAVE ASSISTED EXTRACTION METHOD (MAE) WITH NATURAL DEEP EUTECTIC SOLVENTS (NADES)

Ethanol extract from the leaves of Morus alba, an herb, has been widely used for medicine, including commercial formulations. This study aims to compare the characteristics of NADES extract using the MAE method and the maceration method. Mulberry leaf simplicia (Morus alba. L) ethanol extract was made with various ethanol concentrations of 50%, 60%, 70%, 80%, and 90%, and NADES (Natural Deep Eutectic Solvents) extract with a solvent ratio of 1:20 and 1: 30 on the MAE (Microwave Assisted Extraction) method with a time of 5 and 10 minutes. Measurement of total flavonoid content and total phenolic content was carried out by UV-vis spectrophotometry with quercetin and gallic acid as reference standards. The results showed that the ethanol extract with ethanol concentrations of 50%, 60%, 70%, 80%, and 90% had an average total flavonoid content; and total phenolic: 0.73%, 0.9%, 1.32%, 1.18%, 0.77%; total phenolic 96.789 mg/g, 71.262 mg/g, 126.465 mg/g, 116.643 mg/g, 93.366 mg/g. NADES extract with a solvent ratio of 1:20 at MAE 5" and 10" minutes obtained flavonoid levels of 0.36%, 0.4%, and total phenolic levels of 36.099 mg/g; 75.621 mg/g. While a ratio of 1:30 with an MAE time of 5" and 10" minutes, the flavonoid content was 0.44%; 0.48%, and the total phenolic content of 61.884 mg/g; 121.237 mg/g. Results of water-soluble essence of ethanol extract; NADES is 26%–31%; 21–24%. Result of ethanol soluble extract content of ethanol extract; NADES is in the range of 36%–42%; 85%–86%. Result of the specific gravity of ethanol extract; NADES is in the range of 0.82 g/mL–0.95 g/mL; 1.08 g/mL–1.18 g/mL. The ethanol extract pH test results were; NADES in the range 6.90–7.01; 7.59–7.89.

Determination and Comparison of Bioactive Compounds in Different Parts of Glycyrrhiza Species

Glycyrrhiza spp., one of the most widely used herbal medicine for centuries in the world, contain a large number of bioactive such as triterpene saponins and flavonoids which are the main constituents and show broad biological activity. The present study aimed to evaluate the phytochemical profile of extracts from different parts (roots, stems and leaves) of all wild Glycyrrhiza spp. grown in Turkey and to reveal that other parts besides the roots are a rich source of bioactive compounds with potential use in the pharmaceutical and food industries. For this purpose, extracted bioactive compounds from different parts of five Glycyrrhiza spp. collected in different provinces of Turkey were determined and compared. The microwave-assisted extraction method, which is mentioned as a green technique and requires low solvent and extraction time, was applied. Determination of bioactives was performed using liquid chromatography- electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). Among the collected Glycyrrhiza spp.; in leaf parts, the highest glycyrrhizin (GL) (2.05±0.07 mg g-1) and glycyrrhetinic acid (GA) (0.107±0.005 mg g-1) contents were found in Glycyrrhiza flavescens ssp. flavescens; the highest carbenoxolone (CBX) (0.133±0.006 mg g-1) and liquiritin (LQ) (1.644±0.014mg g-1) contents were in Glycyrrhiza glabra grown in Polatlı. In stem parts, the highest GL (2.735±0.04 mg g-1), CBX (0.069±0.004 mg g-1) and LQ (0.602±0.010 mg g-1) contents were determined in G. glabra plant growing in Ankara. In root parts, the highest GL (14.68±0.09 mg g-1) and LQ (9.735±0.046 mg g-1) contents were detected in G. glabra plant growing in Gaziantep while the highest GA (0.136±0.005 mg g-1) and CBX (0.188±0.067 mg g-1) contents in Glycyrrhiza flavescens ssp. antalyensis. Thus, it was determined which location in Turkey and which parts of Glycyrrhiza spp. that grow wild in Turkey can be used as a priority for the food and pharmaceutical industry with this study.

Enhanced Recovery of Natural Antioxidants from Grape Waste Using Natural Eutectic Solvents-Based Microwave-Assisted Extraction.

The evaluation of sustainable solvents as alternatives to more harmful conventional solvents combined with intensification techniques to recover phenolic compounds from agri-food waste is in the spotlight. The wine industry generates large amounts of waste as a consequence of grape processing operations, which can be revalued by solvent extraction of valuable antioxidants for food and fine chemical applications. Therefore, the present study focuses on the use of natural eutectic solvents (NAESs) with benign environmental, health, and safety profiles, for valorization of grape waste in the context of a circular economy. Herein, up to 15 NAESs consisting of combinations of three hydrogen bond acceptors (choline chloride, L-proline, and betaine) and four hydrogen bond donors (1,2-propanediol, glycerol, and 1,2- and 1,3-butanediol) were evaluated for antioxidant recovery. After an initial screening of the performance of NAESs by conventional extraction, the process was intensified by microwave-assisted extraction (MAE). The extracts were analyzed by UV/VIS spectrophotometric and HPLC methods. Promising results were obtained with the solvent betaine, 1,2-butanediol [1:4], using MAE at 100 °C for 3 min. Overall, the proposed NAESs-based MAE method was successfully applied to recover target compounds from grape waste, with great prospects for the antioxidants market and sustainable development for the winery sector.

Potential Use of Quercus dalechampii Ten. and Q. frainetto Ten. Barks Extracts as Antimicrobial, Enzyme Inhibitory, Antioxidant and Cytotoxic Agents

The bark resulted as a by-product after different Quercus sp. processing is a valuable alternative source of phenolic compounds (mainly tannins). Hence, the focus of the present work was to obtain eight extracts from the rhytidome of the less-studied Q. dalechampii and Q. frainetto and characterize them in terms of chemical and bioactive profiles. Ultrasound and microwave-assisted extraction methods were used for the preparation of the extracts. Total phenolic and tannin contents were assessed through classic spectrophotometric methods, while several individual phenolic compounds were identified and quantified using UPLC-PDA. Antioxidant, enzyme-inhibitory, antibacterial, and cytotoxic activities were tested using in vitro assays; additionally being evaluated was the ability of the extracts to inhibit the adherence of MRSA to suture wires. The UPLC analysis confirmed the presence of gallic acid, catechin, taxifolin, vanillic acid, epicatechin, and caffeic acid. The results showed that tested extracts were able to exert cytotoxic effects, at 6% and 3% concentrations, on confluent cells. The tested solutions inhibit α-glucosidase activity and the antibacterial potential suggested a mild to moderate effect against the Gram-positive strains. Overall, the obtained results revealed rich phenolic and tannin contents for the extracts obtained from both species through microwave-assisted extraction, probably responsible for their mild antibacterial and cytotoxic effects.

SCREENING OF LIPID CONTENTS OF MICROALGAE BY OPTIMIZATION OF OIL EXTRACTION PROCESSES

Currently microalgae are considered as an efficient biological producer of oil.Present study was conducted to explore the lipid yield percentage of three microalgal strains Chlorellasp., Oedogonium sp. and Spirogyra sp. Bligh and Dyer, Soxhlet, Folch and Microwave assistedextraction methods were employed for oil extraction. It was observed that Bligh and Dyer method withChloroform-methanol (1:2, v/v) gave maximum extraction yield (15.46 ± 0.240 %) for Chlorella sp.whereas Folch method with chloroform-methanol (2:1, v/v) gave more lipid yield as compared toBligh and Dyer method i.e 5.53 ± 0.240 % for Spirogyra sp., 13.67 ± 0.240 % and 19.69 ± 0.667 % forOedogonium sp. and Chlorella sp. respectively. Soxhlet extraction resulted in less (14.5± 0.45)percentage yield as compared to Bligh and Dyer and Folch method (16.7± 0.24). Microwave assistedextraction with chloroform- methanol resulted in highest lipid yield (30%) with Chlorella sp.indicating that it contained the maximum lipid content among all the three species.

Optimization of microwave-assisted extraction on polyphenol metabolite from Eleutherine bulbosa (Mill.) urb. bulbs using response surface methodology.

Eleutherine bulbosa bulbs, an endemic plant in Indonesia, have enormous potential as raw materials for pharmaceutical products. Therefore, it is necessary to strengthen and develop extraction methods that are easy, rapid, and efficient to enrich targeted secondary metabolites. This study aims to optimize the microwave-assisted extraction (MAE) method conditions for polyphenol metabolite from E. bulbosa bulbs. The MAE method (with different conditions) was applied to extract total polyphenol content (TPC) from E. bulbosa bulbs. TPC values were determined using a 96-well microplate reader spectrophotometry method and Folin-Ciocalteu reagent. The variables of MAE, as an experimental design-independent variable, were involved. The MAE method condition was optimized using response surface methodology (RSM) and Box-Behnken design based on the TPC value. The MAE condition was optimized with 60% ethanol, sample-solvent ratio of 1:10 g/mL, and 50% Watts of microwave power for 10 min. The quadratic regression analysis was achieved to predict the TPC value using the equation: TPC value = 28.63-5.545A +2.211B -0.741C +1.995D - 4.045AB +0.856AC -7.541BC +1.961CD -8.342A2-0.071B2 +1.840C2-1.535D2. For the scale-up confirmation test, a 50-g sample was used to prove the validity of the equation to predict the TPC value, yielding 35.33 ± 2.13 mg gallic acid equivalent/g samples. The optimum of the MAE condition recommended based on the results of RSM analysis can be applied directly to the enrichment of polyphenols metabolite constituent of E. bulbosa easily, cheaply, quickly, and efficiently.

Comparison of different technologies using organic acid and mineral acid solvents on pectin extraction from apple pomace

Pectin is one of the most widely used functional polysaccharide, which is extensively used in food, biotechnological, chemical, cosmetic, and pharmaceutical industries. Pectin can be suitably extracted from apple pomace which is the main by-product of apple juice industry. In this study, pectin obtained from microwave assisted extraction (MAE) and conventional extraction (CE) were compared in terms of extraction yield, extraction time and extraction temperature. The type of acids namely organic acids and mineral acids were also compared, in which pectin from apple pomace was extracted using different concentration of organic acid (citric acid, 0.1 M and 0.05 M) and mineral acid (hydrochloric acid, 0.1 M and 0.05 M). The best extraction condition of the extraction process was found to be higher in yield by using citric acid at microwave power of 180 W, solid-to-liquid ratio of (1:25), concentration of citric acid of 0.1 M for 90 s. Under these conditions, the extraction yield of pectin reached 19.1 ± 0.2%, methoxyl content (5.27%), anhydroglacturonic acid (43.38%) and degree of esterification (68.97%). The current work showed that critic acid is a ‘green’ and safe acidic solvent that could be used to extract pectin from apple pomace that was highly competitive and environmentally friendly process. The microwave Assisted extraction method is considered to be a potential alternative conventional (traditional) extraction method. The obtained data undertakes that apple pomace obtained by the green extraction has a great potential to be a valuable source of pectin, while preserving similar quality to conventional sources of pectin.

Regeneration of spent bleaching earth using microwave assisted extraction method with hexane as solvent for the bleaching of crude palm oil

One of the wastes in palm oil mills is spent bleaching earth (SBE) which is produced from the bleaching process. In landfills, SBE can produce unpleasant odors, pollute the land and can be quickly oxidized and spontaneously auto ignition occurs. SBE consists of residual oil, phospholipids and several minor components resulting from the bleaching process. Microwave-assisted extraction (MAE) has several advantages over conventional extraction methods because its selective heating increases the effectiveness of the extraction process. The effect of different variables such as irradiation power, contact time and solid to solvent ratio was investigated. After extraction, regenerated spent bleaching earth (RSBE) is used in the bleaching of palm oil with activated bleaching earth (ABE) as a comparison. From this study it can be concluded that MAE can be used in the regeneration of SBE with hexane as solvent. The best conditions for each variable were an extraction time of 40 minutes, a solid to liquid ratio of 1: 4 and a microwave power of 450 W. Using RSBE, the highest yield obtained was 18.63%. Thus, RSBE can be reused in the bleaching process. However, to obtain the same quality results as treated using ABE, more RSBE is needed.

Effect of Ethanol Solution Concentration in the Extraction Process of Centella asiatica L. Bioactive Components Using Microwave-Assisted Extraction (MAE) Method

The Pegagan plant has a scientific name in the form of Centella asiatica L. which is included in the Centella genus, Apiaceae family, and kingdom Plantae. Pegagan (Centella asiatica L.) has distinctive bioactive components, namely triterpene ester glycoside compounds in the form of asiaticoside and madecassoside, and triterpene group compounds in the form of Asiatic acid and madecassic acid. In this study, the extraction of bioactive components from pegagan was carried out using the Microwave-Assisted Extraction (MAE) method and will study the effect of ethanol solvent concentration in the extraction of bioactive compounds. Analysis of the extracted bioactive content was carried out by analyzing the total phenol content using the Folin-Ciocalteau reagent and ANOVA analysis. The results obtained from the study were in the form of total phenol content as an indication of the presence of bioactive compounds, namely at operating conditions of 450 watts of power, 50% ethanol concentration with a radiation time of 15 minutes which resulted in a total phenol content of 21.9244 mg AGE/g sample. In the ANOVA analysis with ethanol solvent, variables that gave a significant response to the total phenol content were microwave power, radiation time, and ethanol concentration with an R-square value of 95.31%. The effect of ethanol concentration on the total phenol content produced, namely the concentration of pure ethanol solvent will produce extracts with the smallest total phenol content, the effect of extraction time on total phenol content, namely the longer extraction time will increase the total phenol content. Maximum total phenol content using ethanol solvent that is, at operating conditions of 450 watts of power, 10% ethanol concentration with a radiation time of 15 minutes which resulted in a total phenol content of 520 mg AGE/g sample.

Effect of different extraction methods on saffron antioxidant activity, total phenolic and crocin contents and the protective effect of saffron extract on the oxidative stability of common vegetable oils

Saffron consists of bioactive compounds with health-promoting properties and is mainly used in medicine, flavoring and coloring. In this study, we aimed to investigate the effect of extraction methods on the antioxidant activity of saffron (Crocus sativus L.) extracts (SE) and to evaluate the antioxidant performance of SE in vegetable oils. Saffron stigmas were extracted in water, ethanol, methanol, and their combinations using maceration extraction (ME), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), and the combination of UAE with MAE. The results showed that the sample extracted by methanol/water (50:50) using the combination of UAE with MAE methods had the highest amount of total phenolic content (31.56 mg/g GAE) and antioxidant activity (83.24% inhibition). The extract with the highest antioxidant activity was freeze-dried before incorporation into oil samples. Freeze-dried SE contained trans-crocin-4 and trans-crocin-3 (most abundant constituents), kaempferol, and picrocrocin. Moreover, the addition of SE at 1000 ppm resulted in a significant increase in the oxidative stability of canola (CAO), sunflower (SO), and corn oil (COO).

Comparison of microwave, ultrasound and ultrasound-microwave assisted solvent extraction methods on phenolic profile and antioxidant activity of extracts from jackfruit (Artocarpus heterophyllus Lam.) pulp

This study aimed to investigate the impact of different solvents (water, 60% methanol, 60% ethanol and 60% acetone) and methods (conventional solvent extraction, ultrasound-assisted extraction, microwave-assisted extraction and ultrasound-microwave assisted extraction) on the phenolic profile and antioxidant activity of jackfruit (Artocarpus heterophyllus Lam.) pulp. The Folin-Ciocalteu assay was used to determine the total phenolic content (TPC), and antioxidant activity was measured by DPPH and ABTS assays. The phenolic profiles in different extracts were identified using the UPLC-ESI-Q-TOF-MS/MS technique. The results showed that significant differences (p < 0.05) in TPC were found among different extraction methods, the microwave-assisted extraction with 60% ethanol had the highest TPC (2.40 mg GAE/g) compared with the extracts obtained from other methods. Meanwhile, the highest DPPH radical and ABTS radical cation was found in the 60% ethanol-MAE extracts. Correlation analysis further showed a significant positive correlation between TPC and antioxidant activity (R2 > 0.8, p < 0.001). Seventy-eight phenolic compounds were identified by UPLC-ESI-Q-TOF-MS/MS analysis. The most abundant phenolic compounds in jackfruit pulp were identified in negative mode, with 60% ethanol-MAE being the most effective. The quantity of phenolic compounds extracted varied with different extraction methods indicated that the extraction methods had effects on the phytochemical characteristics.

Optimization of Microwave-Assisted Extraction Method for Increased Extraction Yield and Total Phenol Content from Moringa Leaves (Moringa oleifera Lam.) var. PKM 1

Moringa (Moringa oleifera Lam.) is an incredible plant with a storehouse of essential nutrients such as proteins, vitamins, minerals, and phytochemicals such as phenols, flavonoids, glycosides, and sterioids. From the qualitative screening, phytochemical was highly present in hydroethanolic extracts. Through hydroethanolic extraction, the recovery of these biomolecules could be achieved throughadvanced novel extraction methods such as microwave-assisted extraction. The main aim of this experimental trial is to optimize three independent factors including power (500 W–700 W), temperature (30°C–50°C), and extraction time (20 min–40 min) consisting of two levels of dependent variables such as extraction yield (EY) and total phenol content (TPC) using Response Surface Methodology (RSM) constructed by Central Composite Design (CCD) with 20 trial runs. The optimized extraction method recorded 14.64 to 17.65% of extraction yield and 63.36 to 76.40 mg GA/gram of total phenol content. As a result of the optimization of microwave-assisted extraction, the recovery of biomolecules from the dried moringa leaves is achieved by increasing the extraction temperature and time with the microwave power of the instrument.

Optimization of a Microwave Assisted Extraction Method for Maximum Flavonols and Antioxidant Activity of Onion Extracts.

Nowadays, consumers demand bioactive foods that have the potential to limit the risk of suffering from several medical conditions. Onions present these desirable capabilities owing to its high content in antioxidant bioactive compounds. This work has used a Box-Behnken design with a response surface methodology to determine the best conditions in which to extract the polyphenols that are found in onions. Two extraction methods-one for the extraction of total flavonols and another one intended to obtain extracts with the highest possible antioxidant activity-have been developed and optimized. The following factors have been studied: temperature, %methanol in water, solvent pH, and sample-solvent volumetric ratio. The optimal conditions for the extraction of flavonols were 93.8% methanol in water, pH 2, 50 °C extraction temperature and 0.2:17.9 g:mL sample-solvent ratio. The best antioxidant activity levels were registered when using 74.2% methanol in water, pH 2, 99.9 °C extraction temperature and 0.2:18.2 g:mL sample-solvent ratio. Both optimized methods used short extraction times, and presented good precision levels and successful results when used with an assortment of onion varieties. According to total flavonols and antioxidant activity data, with 7.557 ± 0.3261 and 12.08 ± 0.0379 mg g-1, respectively, the developed methods achieved comparable or even superior results to those obtained by other authors.

Extraction of rice bran oil using microwave-assisted extraction and green solvents

Rice bran oil (RBO) is a healthy vegetable oil made from rice bran. A microwave- assisted extraction method (MAE) was developed in this work to produce RBO with greater productivity than the conventional method, i.e., solvent extraction (SXE). Furthermore, green solvents such as ethanol and d-limonene were compared as an alternative to the less environmentally friendly n-hexane. An evaluation of energy consumption and raw material costs was conducted using the MAE method. The 30 mesh bran was stabilized in the oven for 30 min at 100°C followed by MAE extraction, which was performed by mixing 50 g of bran and 300 ml of solvents in a microwave oven set to 450 watts and 60°C for 60 min. Filter paper was used to separate the extract from the bran, and the oil was recovered by solvent evaporation. Finally, the oil was weighed and the fatty acid composition was determined by GC-MS. The results showed that the yield of RBO using d-limonene and MAE was the largest (24.64%) as well as consuming less energy (95Wh/gr oil). Linoleic acid was only found in the extraction with d-limonene and EtOH was successful in obtaining longer-chain saturated fatty acids.

Microwave-assisted extraction, structural elucidation, and in vitro anti-glioma and immunostimulatory activity of polysaccharide from Panax ginseng C. A. Meyer

This paper aimed to elaborate the chemical characteristics of ginseng polysaccharide via chemical methods and instrumental analyses; additionally, the anti-glioma activity and immunostimulatory capacity were also evaluated via biological experiments. Ginseng polysaccharide by microwave-assisted extraction (MEGP) method was purified by spongiform diethylaminoethyl cellulose (DEAE) and further separated by DEAE-52 column chromatography to obtain four MEGP fractions (MEGP-0, MEGP-1, MEGP-2, MEGP-3). Utilizing Zeta potential analyzer and X-ray photoelectron spectroscopy (XPS), MEGPs were, for the first time, confirmed the valence state of C and O with the binding mode of elements, and all MEGP fractions contained triple-helix structure. MEGP-2 and MEGP-3 significantly reduced the cell growth rate of TJ905 and U87, showing an inhibitory effect on glioma. Among four fractions, MEGP-2 markedly elevated the immunostimulatory capacity via the activation of MAPK signaling route, with an increasing the expression levels of p-p38, p-ERK and p-JNK. In summary, this paper laid a solid foundation for the development of ginseng, as a promising drug or tonic, in the fields of anti-glioma and immunoregulation.

The Effects of Solvent Ratio and Extraction Time on Physicochemical Characteristics of Stevia Leaf Liquid Extract Using Microwave Assisted Extraction Method

Stevia (Stevia rebaudiana Bertoni) is one of the natural sweeteners which contains low calorie and can be used as a substitute for sugar. The purpose of this study was to determine the effects of solvent ratio and extraction time to the physicochemical characteristics of stevia leaf liquid extract using microwave assisted extraction methods. The observed characteristics were yield of extraction, total soluble solids content, specific gravity and color. The method used in this research was a laboratory experiment with descriptive analysis using 3 different extraction time, which is 4, 5 and 6 minutes. The solvent ratio used in this study were 3 levels, which is 1:30; 1:35 and 1:40 (w/v). The result of this study indicated that extraction variations with material:solvent ratio of 1:30 (w/v) and extraction time of 6 minutes produced the best total soluble solid contents with a value of 2oBrix, meanwhile extraction variations with material:solvent ratio of 1:40 (w/v) and extraction time of 4 minutes produced the best yield of extraction with a value of 87.95%.

INHIBTOR KOROSI DARI EKSTRAKSI DAUN TEMBAKAU DENGAN METODE MICROWAVE ASSISTED EXTRACTION (MAE) PADA BERBAGAI LINGKUNGAN

Corrosion is a metal material damage due to environmental interaction and affect to human life. If corrosion not handled well it can cause industry component broken and also cause great environmental damage. Corrosion prevention can be done with adding natural based corrosion inhibitor to corrosion environment. One of natural based material for corrosion inhibitor is tobacco leaf because it contains flavonoid and nitrogen base to inhibit corrosion rate. Tobacco leaf extraction can he done using microwave-assisted extraction (MAE) method that means micro wave base extraction process. This research vary micro wave power, time extraction, rasio feed to solvent and heating temperature to produce tobacco leaf corrosion inhibitor. Implementation of this research can be done by literature study, decide, independent variable, and dependent variable. Independent variables are corrosive environment (HCl 0,5 M; NaOH 1M, and tap water), extraction time (10 menit, 12 menit, 14 menit, 16 menit, dan 18 menit), microwave power (150 Watt dan 300 Watt), and metal plat Fe . Beside that, dependent variable is 60 mesh solid size tobacco leaf that dissolved using ethanol with 0,275 gram sample/mL rasio feed to solvent. This research begins with raw materials and tools preparation, tobacco leaf extraction process, and corrosion inhibitor test. The result results of this research are the biggest efficiency occurred in Sodium Hydroxide environment with corrosion rate 0,09268 mpy and 98,5003&amp; efficiency. Sample test with mayer reagent, wagner reagent, and dragendorf reagent indicate that there is alcoloid exist.

Microwave-Assisted Extraction of Fucoidan from Sargassum plagiophyllum and its Activities.

&lt;b&gt;Background and Objective:&lt;/b&gt; Fucoidan extract from the &lt;i&gt;Sargassum plagiophyllum &lt;/i&gt;brown seaweed are renowned for its anticancer and antibacterial activities. Fucoidan is one of the ingredients of &lt;i&gt;S. plagiophyllum &lt;/i&gt;that can be extracted by conventional methods and new methods, one of which is microwave assisted extraction (MAE). Research on the extraction of fucoidan from &lt;i&gt;S. plagiophyllum &lt;/i&gt;was still limited. Thus, an advanced experiment on how microwave assisted extraction (MAE) of fucoidan was conducted in this study and its activities against &lt;i&gt;Escherichia coli &lt;/i&gt;bacteria and HeLa cancer cells were studied. &lt;b&gt;Materials and Methods:&lt;/b&gt; &lt;i&gt;Sargassum plagiophyllum &lt;/i&gt;was collected from the Gunung Kidul Coast in Yogyakarta, Indonesia. Fucoidan extract of &lt;i&gt;S. plagiophyllum&lt;/i&gt; was acquired by applying the MAE method at 600 W for 5 min and using hydrochloric acid as a solvent. The cytotoxicity and antibacterial assays were performed using the MTT assay and the agar plate diffusion methods, respectively. &lt;b&gt;Results:&lt;/b&gt; The yield of the fucoidan extract examined was 9.90% (w/w), which consisted of 2.60% sulfate and 2.33 mg 100 g&lt;sup&gt;1&lt;/sup&gt; fucose. The finding indicated that fucoidan extract exhibits no antibacterial action and the cytotoxicity against the HeLa cell line was 27.82 mg mL&lt;sup&gt;1&lt;/sup&gt;. &lt;b&gt;Conclusion:&lt;/b&gt; The MAE technique was proven to support the fucoidan extraction from &lt;i&gt;S. plagiophyllum &lt;/i&gt;successfully. Therefore, the fucoidan extract has proven to have promise beneficial in anticancer activity.