Ultrasound-assisted Extraction Parameters Research Articles

Ultrasound-Assisted Extraction of Bioactive Compounds from Broccoli By-Products.

The objective of this work was to gain insight into the operating conditions that affect the efficiency of ultrasound-assisted extraction (UAE) parameters to achieve the best recovery of bioactive compounds from broccoli leaf and floret byproducts. Therefore, total phenolic content (TPC) and the main sulfur bioactive compounds (sulforaphane (SFN) and glucosinolates (GLSs)) were assayed. Distilled water was used as solvent. For each byproduct type, solid/liquid ratio (1:25 and 2:25 g/mL), temperature (25, 40, and 55 °C), and extraction time (2.5, 5, 7.5, 10, 15, and 20 min) were the studied variables to optimize the UAE process by using a kinetic and a cubic regression model. TPC was 12.5-fold higher in broccoli leaves than in florets, while SFN was from 2.5- to 4.5-fold higher in florets regarding the leaf's extracts obtained from the same plants, their precursors (GLS) being in similar amounts for both plant tissues. The most efficient extraction conditions were at 25 °C, ratio 2:25, and during 15 or 20 min according to the target phytochemical to extract. In conclusion, the type of plant tissue and used ratio significantly influenced the extraction of bioactive compounds, the most efficient UAE parameters being those with lower energy consumption.

Ultrasound assisted extraction of amino acids and nucleobases from clay minerals and astrobiological samples

The study of organic molecules in meteorite and return samples allows for the understanding of the chemistry that undergoes in our Solar System. The present work aims at studying ultrasound assisted extraction technique as effective extraction method for these molecules in extraterrestrial samples and analogs. Optimal conditions were selected from the investigation of ultrasonic frequency, irradiation duration and solvent effects on amino acids, nucleobases and dipeptides extraction yields from a model clay-rich mineral matrix. Optimal ultrasound-assisted extraction parameters were frequency of 20 kHz within 20 min irradiation time and methanol/water solvent ratio of 1. We then validated this protocol on Mukundpura and Tarda meteorite fragments and compared it to the reference extraction protocol used in astrobiology and based on 24 h extraction time at 100 °C in water We obtained similar quantitative results without any racemization with both methodologies.

Ultrasound assisted phytochemical extraction of red cabbage by using deep eutectic solvent: Modelling using ANFIS and optimization by genetic algorithms

The present investigation studied the effect of process parameters on the extraction of phytochemicals from red cabbage by the application of ultrasonication and temperature. The solvent selected for the study was deep eutectic solvent (DES) prepared by choline chloride and citric acid. The ultrasound assisted extraction process was modeled using adaptive neuro-fuzzy inference system (ANFIS) algorithm and integrated with the genetic algorithm for optimization purposes. The independent variables that influenced the responses (total phenolic content, antioxidant activity, total anthocyanin activity, and total flavonoid content) were ultrasonication power, temperature, molar ratio of DES, and water content of DES. Each ANFIS model was formed by the training of three Gaussian-type membership functions (MF) for each input, trained by a hybrid algorithm with 500 epochs and linear type MF for output MF. The ANFIS model predicted each response close to the experimental data which is evident by the statistical parameters (R2>0.953 and RMSE <1.165). The integrated hybrid ANFIS-GA algorithm predicted the optimized condition for the process parameters of ultrasound assisted extraction of phytochemicals from red cabbage was found to be 252.114 W for ultrasonication power, 52.715 °C of temperature, 2.0677:1 of molar ratio of DES and 25.947 % of water content in DES solvent with maximum extraction content of responses, with fitness value 3.352. The relative deviation between the experimental and ANFIS predicted values for total phenolic content, antioxidant activity, total anthocyanin activity, and total flavonoid content was found to be 1.849 %, 3.495 %, 2.801 %, and 4.661 % respectively.

Recovery of antioxidants and oils from blackcurrant and redcurrant wastes by ultrasound-assisted extraction

An investigation of the ultrasound-assisted extraction (UAE) of polyphenols and oils from blackcurrant and redcurrant pomaces was carried out. The aim of the study was to select optimal conditions for the UAE process in order to obtain polyphenol-rich extracts with highest total polyphenol content and highest antioxidant capacity. In case of oils, the optimization was focused on choosing the UAE parameters to achieve the highest oil yield and the longest oxidation induction times. The most effective conditions of UAE were provided by the results of response surface methodology procedure, which involved variables of time (2–10 min) and ultrasound amplitude (30%–80%). Solvents used for extractions were distilled water and n-hexane for bioactive compounds and oils extractions, respectively. In terms of polyphenol-rich fractions the most effective conditions were: amplitude of around 51% and 3 min time for blackcurrant pomace and amplitude of around 91% and 11 min time for redcurrant pomace. In case of oils, the amplitude of 99% and 11.5 min time were chosen for blackcurrant. For redcurrant seed oil it was the amplitude of 96% and extraction time equal to 12 min. The actual results obtained in optimized conditions were comparable to the results predicted by models. It was proved that response surface methodology could be useful tool in optimization of UAE process for blackcurrant and redcurrant polyphenol-rich extracts and seed oils.

Sustainable Ultrasound Assisted Extractions and Valorization of Coffee Silver Skin (CS)

The Sustainable Development Goals (SDG) encourage the efficient use of sustainable technologies. Ultrasound-assisted extraction (UAE) is one of the extraction process techniques, which are also directed towards sustainability as a goal. Coffee silver skin (CS), being a healthy raw material as well as a waste, could be utilized in the manufacturing process of new dietary products. The goal of this research was to isolate proteins and polyphenols from CS using UAE and to employ spectrophotometry to determine the yields. Three parts of the research were conducted: ultrasonic extraction, the optimization of UAE conditions for the isolation of proteins and polyphenols from CS, and the analysis of the amino acid extract obtained with the optimal use of UAE. According to the results, it was reported that the highest yields of total polyphenols isolated from the CS using UAE were obtained by applying an amplitude of 75% and a time interval of 9 min. The optimal parameters of UAE, when considering the proportions of total polyphenols and proteins, are an amplitude of 100% and a time of 9 min. The most abundant amino acids in isolated proteins (Asp, Glu, Pro, Gly, and Ala) were defined as well. Based on the use of energy, it was obvious that UAE is a promising technology. This concurs with the proposed practice that when non-thermal technologies are analyzed from an environmental point of view, the first common denominator is the use of electricity to run the equipment, in relation to resource depletion. As expected, CS poses a great waste to be recycled, being a nutritionally rich raw material with great potential. Quantitative consideration on the environmentally friendly applicability of CS in mass production should be carried out to validate the entire process of developing a new product from both economic and environmental aspects.

Evaluation of Microwave- and Ultrasound-Assisted Extraction Techniques for Revalorization of Black Chokeberry (Aronia melanocarpa) Fruit Pomace Anthocyanins

Black chokeberry juice production results in a large amount of pomace, which is usually regarded as waste. Nevertheless, it contains significant amounts of anthocyanins, which can be utilized as health-promoting components, but also as food colorants. To take advantage of their benefits, green extraction methods such as microwave-assisted (MAE) and ultrasound-assisted extraction (UAE) are widely used for their isolation. This study aimed to evaluate the effects of MAE and UAE parameters (solvent, treatment time, temperature, or ultrasound amplitude) on the extraction yield of anthocyanins from black chokeberry pomace and to compare the effectiveness of these two green extraction methods with conventional reflux extraction, both in terms of total anthocyanins yield and effects on individual compounds. In both techniques, acidification of the extraction solvent did not show a significant effect on anthocyanin content. For MAE, a temperature increase from 40 to 60 °C positively affected the extraction yield, while 4 min was a substantial treatment time for the extraction. Conversely, UAE required 10 min of treatment time with no effect on amplitude. UPLC ESI-MS2 analysis confirmed the presence of 6 anthocyanins in the obtained extracts, with significantly higher levels of cyanidin-3-O-xyloside and cyanidin-3-O-arabinoside were in ones isolated by green extraction techniques.

The effect of ultrasound on improving the extraction of tannins from the Stryphnodendron adstringens bark

Stryphnodendron adstringens (Barbatimão) barks is one of the plants listed in the national list of medicinal plants of interest to the Brazilian health system and in the Brazilian pharmacopeia. Its extracts have been used in commercial products and popular medicine due to their phenolic compound's composition. Reported works dealing with Barbatimão and ultrasound-assisted extraction (UAE) does not cover all possible variables to be studied. Also, there is a gap in understanding the ultrasound phenomena's effect on the extract composition and biological properties of the Barbatimão. This work aimed to apply the UAE, using hydroethanolic solution (50 wt%) as the solvent to recover phenolic compounds from Barbatimão barks. Amplitude (0–40%), solvent-to-feed mass ratio (5-25), and extraction time (2–12 min) were evaluated. Ferric-reducing antioxidant capacity (FRAP), antioxidant cell activity, and cytotoxicity were also evaluated. The results showed that UAE parameters play significant roles in obtaining higher yields of phenolic compounds compared to other processes including conventional techniques. It was identified that the ultrasound waves contribute to enhancing the tannin extraction through mechanisms that only ultrasound, among the tested techniques, can provide. The extract obtained by UAE promoted cell viability higher than 80%, while the extracts obtained by the conventional method did not demonstrate this activity. UAE showed an efficient technique to obtain a tannins-rich extract from Barbatimãobarks.

Extraction and recovery of bioactive soluble phenolic compounds from brocade orange (Citrus sinensis) peels: Effect of different extraction methods thereon

Brocade orange peels (BOPs), typically treated as discardable residue, contain large amounts of bioactive phenols that can serve as ingredients for value-added products with health-promoting effects. Given this, this study developed a response surface model to optimize the conditions for ultrasound-assisted extraction (UAE). The total phenol and flavonoid contents (TPC, TFC), profiles, and antioxidant activities of peel extracts for free, esterified, and glycosylated-bound phenols (FPs, EBPs, and GBPs) served as metrics for comparing the recoveries using UAE, conventional solvent extraction (CSE), and enzyme-assisted extraction (EAE). The maximum values of practical TPC and TFC achievable under the optimal UAE parameters (17.6 mL/g, 28 min, 26 °C, and 60 W) were 24.07 GAE/DW and 8.34 mg RE/DW, respectively. Extraction methods and especially phenolic fractions were found to exert extremely significant effects on the profiles and bioactivities. For any given phenolic fraction, UAE and particularly EAE were generally superior to CSE in terms of yield and quality of recovered phenolic compounds, as measured according to DPPH and ABTS free radical scavenging capacities. Meanwhile, Observations of predominant levels of polymethoxyflavones in FPs, ferulic acid in EBPs, and hesperetin in GBPs provides a basis for future efforts to obtain specific bioactive phenolic compounds from natural sources.

The Application of Ultrasonic Waves and Microwaves to Improve Antihyperglycaemic and Antimicrobial Activities of Marrubium vulgare Extracts.

Having scarce information about ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) of white horehound (Marrubium vulgare L.), the idea has emerged to determine the optimal process parameters for the maximization of polyphenols and to compare the efficiency of these green extraction technologies. The optimal UAE parameters are temperature of 73.6 °C, extraction time of 40 min and ultrasound power of 30.3 W/L, while the optimal MAE parameters are 63.8% ethanol, extraction time of 15 min and microwave power of 422 W. Extract obtained at optimal UAE parameters shows the highest antihyperglycemic activity (α-amylase inhibition: 50.63% and α-glucosidase inhibition: 48.67%), which can potentially be explained by the presence of chlorogenic acid and quercetin, which were not identified in the macerates. The most sensitive bacterial strain to optimal ultrasonic extract is Bacillus cereus, whereas the most sensitive fungal strain is Saccharomyces cerevisiae.

Central composite experimental design for ultrasound‐assisted extraction optimization of alkaloid compounds and antioxidant properties from cocoa pod husk ( Theobroma cacao L.)

The objective of this research was to identify ultrasound-assisted extraction (UAE) parameters for maximizing alkaloid yield and antioxidant activity from cocoa pod husk (CPH). The findings indicated that the optimum UAE parameters were extraction temperature 60°C, extraction time 50 min, and solvent to sample ratio 50 ml/g. Under these UAE parameters, total alkaloid content (TAC), alkaloid extraction efficiency (AEE), DPPH radical scavenging capacity (DRSC), and ferric reducing antioxidant power (FRAP) obtained from the CPH were 45.62 mg AE/g dried sample (DS), 63.28%, 16.57, and 2.15 mg TE/g DS, respectively, which were not significantly different (p < .05) from the predicted values (42.57 mg AE/g DS, 59.04%, 15.06 and 0.99 mg TE/g DS, respectively). The residual moisture, water activity, density, water soluble index, and pH of enriched-alkaloids powder from the CPH were 7.66%, 0.39, 0.13 g/ml, 93.77%, and 5.08, respectively. TAC, total phenolic content (TPC), total flavonoid content (TFC), and total saponin content (TSC) of powder were 655.43 mg AE/g DS, 33.60 mg GAE/g DS, 48.51 mg CE/g DS, and 186.48 mg EE/g DS, respectively. ABTS radical scavenging capacity (ARSC), DRSC, cupric reducing antioxidant capacity (CUPRAC) and FRAP of powder were 84.48, 49.54, 155.01, and 6.01 mg TE/g DS, respectively. The results achieved from this study imply that the powder obtained from the CPH is a rich source of alkaloids. Thus, it is a potential candidate for application in the functional food and nutraceutical industries. Practical applications Cocoa pod husk is generated in huge amounts and is a rich source of alkaloids. Recovery of alkaloids from the CPH for potential application in the functional foods and nutraceuticals not only increases value for cocoa tree but also reduces pollution risk to environment.

A Rapid and Efficient Strategy for Quality Control of Clinopodii herba Encompassing Optimized Ultrasound-Assisted Extraction Coupled with Sensitive Variable Wavelength Detection.

Clinopodii herba is a folk herbal medicine for treatments of hemorrhagic disorders. However, there is not even a quantitative standard for clinopodii herba deposited in the Chinese Pharmacopoeia. The development of a strategy for rapid and efficient extraction and simultaneous detection of multiple components in clinopodii herba is therefore of great value for its quality evaluation. Here, a variable wavelength strategy was firstly applied to quantity multiple components by segmental monitoring by UHPLC with diode array detector following ultrasound-assisted extraction. The parameters of ultrasound-assisted extraction were optimized using single factor optimization experiments and response surface methodology by a Box–Behnken design combined with overall desirability. Subsequently, a rapid, efficient, and sensitive method was applied for simultaneous determination of eleven compounds, which represented the major and main types of components in clinopodii herba. Moreover, the performance of the validated method was successfully applied for the quality control of various batches of clinopodii herba and provided sufficient supporting data for the optimum harvest time. The Box-Behnken-optimized ultrasound-assisted extraction coupled with variable wavelength detection strategy established in this work not only improves the quality control of clinopodii herba, but also serves as a powerful approach that can be extended to quality evaluation of other traditional Chinese medicines.

Optimized Green Extraction of Polyphenols from Cassia javanica L. Petals for Their Application in Sunflower Oil: Anticancer and Antioxidant Properties.

The total phenolic content (TPC) from Cassia javanica L. petals were extracted using ethanolic solvent extraction at concentrations ranging from 0 to 90% and an SCF-CO2 co-solvent at various pressures. Ultrasound-assisted extraction parameters were optimized using response surface methodology (RSM). Antioxidant and anticancer properties of total phenols were assessed. An SCF-CO2 co-solvent extract was nano-encapsulated and applied to sunflower oil without the addition of an antioxidant. The results indicated that the best treatment for retaining TPC and total flavonoids content (TFC) was SCF-CO2 co-solvent followed by the ultrasound and ethanolic extraction procedures. Additionally, the best antioxidant activity by β-carotene/linoleic acid and DPPH free radical-scavenging test systems was observed by SCF-CO2 co-solvent then ultrasound and ethanolic extraction methods. SCF-CO2 co-solvent recorded the highest inhibition % for PC3 (76.20%) and MCF7 (98.70%) and the lowest IC50 value for PC3 (145 µ/mL) and MCF7 (96 µ/mL). It was discovered that fortifying sunflower oil with SCF-CO2 co-solvent nanoparticles had a beneficial effect on free fatty acids and peroxide levels. The SCF-CO2 method was finally found to be superior and could be used in large-scale processing.

A Comprehensive Optimization of Ultrasound-Assisted Extraction for Lycopene Recovery from Tomato Waste and Encapsulation by Spray Drying

This study aimed to extract bioactive compounds from tomato waste through ultrasound-assisted extraction (UAE), using ethanol as solvent. Process optimization was carried out by a central composite design of 33 runs for response surface modelling, simultaneously analyzing the effect of temperature (T), time (t), volume (V), liquid-to-solid ratio (L/S), amplitude (A), the pulser duration (on), and their interaction. The best conditions found by the desirability method (T = 65 °C, t = 20 min, L/S = 72 mL/g, A = 65%, on = 33 s, V = 90 mL) were experimentally verified, leading to the production of an extract with interesting properties (total carotenoids of 1408 ±14 µglycopene equivalents/g, lycopene yield of 1536 ± 53 µg/g, 36.1 ± 0.9 µgtrolox equivalents/g as antiradical power). Due to the instability of lycopene, the extract encapsulation by spray drying was undertaken using inulin and maltodextrins as coating agents. The evaluation of wall material composition provided high product recovery (73%), a high content of encapsulated compared to superficial lycopene (15.3 ± 2.9 and 0.30 ± 0.02 µg/g), and a product with good water solubility. The novelty of this work concerned the simultaneous study of the effect and interdependences of the UAE parameters, and the use of inulin to enhance the properties of microparticles.

Comparison of conventional and ultrasound‐assisted extractions of polyphenols from Inca muña (Clinopodium bolivianum) and their characterization using UPLC–PDA‐ESI–Q/TOF–MSntechnique

This study aimed to optimize the extraction of phenolic compounds (PC) and the antioxidant capacity (AC) of Inca muña by conventional solvent extraction (CSE) and ultrasound assisted extraction (UAE). Optimization was performed by response surface methodology (RSM). CSE evaluated variables included EtOH (%), temperature and time and UAE evaluated variables considered amplitude, time and EtOH (%). Optimal CSE parameters were EtOH (46.3%), temperature (68.7 °C) and time (62.7 min); while optimal UAE parameters were amplitude (70%), time (8.9 min) and EtOH (70%). UAE was more efficient achieving a higher PC extraction (10.4 %) and higher AC (27.2 %) with shorter extraction time. Thus, under optimal conditions, values of total phenolic compounds (T-PC) and AC of 182.2 mg GAE/g and 1470.0 µmol TE/g, were obtained. The extract was mainly composed of chlorogenic acid (isomer) > rosmarinic acid > eriocitrin > naringenin. The extracts obtained are an alternative for various industrial applications.

Optimization of Ultrasound-Assisted Extraction Parameters from Indigofera Tinctoria L using Response Surface Methodology

Nowadays, the natural dyes are commonly used in textile industry. One of them is Indigofera tinctoria L leaves extracting natural dyes that produce blue color and have various potential utilization. However, the extraction time required usually takes a long time using conventional extraction. Thus, some researches reported that ultrasound-assisted extraction can accelerate and increase the extraction yield. The mechanism of ultrasonography is able to assist matrix cell rupture through the ultrasound cavitation. The present research aimed to study and to evaluate the Indigofera tinctoria L dye using ultrasound-assisted extraction. Response surface methodology (RSM) in conjunction with box-behnken design (BBD) was applied to optimize and to analyze the extraction conditions. The independent factors were ratio feed to solvent (0.02-0.1 g/ml), ultrasound temperature (50-60oC), and extraction time (50-90 minutes). Further, feed to solvent ratio was the most significant factor of extraction process in comparison with temperature and extraction time. The optimum extraction conditions were 58oC, 0.02 g/ml, and 50 minutes. The predicted model obtained was 6.025% which close to the actual data (5.75%). Moreover, the extract dye compounds were analyzed by FTIR test and the result was 64.07% for presence of Indigo dye. Therefore, the natural dyes can be alternative and sustainable dye as environmentally friendly

Ultrasound-assisted extraction of boulardii yeast cell wall polysaccharides: Characterization and its biological functions on early-weaned lambs.

Firstly, this study was designed to determine the optimal ultrasound‐assisted extraction parameters of Saccharomyces boulardii yeast wall polysaccharides (BYWP). Besides, the molecular weight and the ratio of mannose to glucose in compositions of BYWP were determined. Also, the effects of BYWP on the gain feed ratio, diarrhea frequency, intestinal morphology, intestinal immunity, and intestinal microbial flora of early‐weaned lambs were investigated. Single‐factor tests and Response surface optimization analysis (RSA) were used to obtain the optimal ultrasound‐assisted extraction conditions. Sephadex G‐100 column chromatography and liquid chromatography were used to analyze the molecular weight and ratio of mannose to glucose. The feeding trial was used to observe the biological functions of BYWP on early‐weaned lambs. A total of 72 36‐day‐old crossbred early‐weaned lambs were randomly divided into 4 groups with 3 replicates per group and 6 lambs per replicate. Lambs in the four treatments were fed basal milk replacer without supplement (Group I), basal milk replacer+0.1% BYWP (Group II), basal milk replacer+0.3% BYWP (Group III), and basal milk replacer+0.5% BYWP (Group IV), respectively. The optimal ultrasound‐assisted extraction parameters were as follows: NaOH addition: 52.63%, ultrasonic power: 143.15 W, ultrasonic time: 86.20 min, and the optimized extraction yield reached 37.54%. The molecular weights of main components BLC‐1 and BLC‐2 were 164.68 KDa and 13.21 KDa, and their proportions in BYWP were 24.57% and 66.08%, respectively. The proportions of glucose, mannose in BLC‐1 and BLC‐2 were 47.68%, 39.18%, and 76.59%, 6.86%, respectively. The addition of 0.3% and 0.5% BYWP in basal milk replacer significantly increased the average daily gain and feed conversion rate, and decreased the average fecal index and diarrhea rate of early‐weaned lambs. The addition of 0.3% and 0.5% BYWP significantly enhanced the intestinal morphology (villus height, crypt depth, and V/C value) of jejunum, ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly improved the levels of SIgA and IL‐10, but significantly decreased the level of IL‐1 in the ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly increased the number of Lactobacillus, but significantly suppressed the growth of Salmonella and Clostridium perfringens (p < .05). The results of the present study suggest that the supplementation of BYWP in the diet of early‐weaned lambs could increase feed utilization rate, and enhance intestinal morphology, immunological competence, microbial flora balance, and decrease the rate of diarrhea occurrence.

A review of the effect of UAE optimization parameters on antioxidant activity

Optimization of Ultrasound-assisted extraction parameters is necessary to determine the optimum level of the parameters, including solvent-to-material ratio, power, extraction time, solvent concentration, temperature, and pH. This review focuses on the UAE parameters’ effects on the antioxidant activity, their interactions, and the best method of examining antioxidant activity to respond to the UAE’s optimization. It was determined that the optimal extraction time is 15 minutes, and any duration longer than that could result in reduction of antioxidant activity. The temperature effect is important, wherein antioxidant activity decreases significantly when the extraction temperature is higher than 45 °C. Increasing the solvent concentration beyond 50% decreased the antioxidant activity. No increase in antioxidant activity was observed with a solvent/sample ratio greater than 40 ml/g. Increased ultrasound power leads to increased antioxidant compounds, especially in the range of ultrasound power, such as 50 to 150 W. However, higher ultrasound power creates free hydroxyl radicals that destroy the antioxidant compound. With an increase in pH, the radical scavenging activity increases significantly. It should, however, be at a near-neutral level, such as pH 6. Comparative literature has shown that optimizing UAE contributes to enhanced antioxidant activity and enhances resource conservation, such as energy and chemicals.

Chemical composition of dried Stevia rebaudiana Bertoni leaves and effect of ultrasound-assisted extraction on total steviosides content in extract

Summary Introduction: Steviol stevioside, which has been used in the production of food products as a low-calorie sweeten, is one of the main glycoside groups in the leaves of the Stevia plants. It is useful for human health. Objective: The main objection of the present study was to find out some major chemical compositions of the dried Stevia rebaudiana Bertoni leaves and an effective, affordable, and environmentally friendly method to reach the high extraction yield of total steviosides from them. Therefore, a novel extraction, ultrasound-assisted extraction (UAE), was carried out to extract total steviosides from dried leaves of S. rebaudiana plant with ethanol of 70% (v/v) as a solvent. Methods: Some major chemical compositions of the dried S. rebaudiana leaves were analyzed according to the AOAC (Association of Official Analytical Chemists) and total steviosides content (TSC) was measured by anthrone-sulphuric acid colorimetric assay with main influencing factors including material/solvent ratio, extraction temperature, and extraction time. Results: The results referred that some chemical compounds such as protein, lipid, fibre, sugar, etc. existed in this material. The best extraction conditions were the sample/solvent ratio of 1:100 (g/ml), extraction temperature of 75oC, and extraction time of 30 min. Conclusion: The highest amount of total steviosides content of 8.894 % was obtained at the optimal extraction condition. Consequently, these results demonstrated that the parameters of UAE were applied successfully for producing total glycosides.

Obtaining antioxidant compounds from the endophytic fungus Diaporthe schini using heat- and ultrasound-assisted extraction

Ultrasound-assisted extraction (UAE) of antioxidant compounds from Diaporthe schini biomass using ethanol as solvent was performed and the results were compared with heat-assisted extraction (HAE; conventional technique). Ultrasound intensity (17–85 W cm−2) and pulse cycle (0.50–1.00) were evaluated according to a Central Composite Rotatable Design (CCRD) to obtain the highest extraction yield. The HAE was studied at 30 and 50 °C. In the validation condition (85 W cm−2 and 0.93) of the UAE the extraction yield and antioxidant capacity (DPPH) were 22.30 ± 0.47% and 91.35 ± 0.27%, respectively. The best extraction yield (8.34 ± 0.38%) and antioxidant activity (91.32 ± 0.98%) of the HAE were observed at 50 oC. The GC/MS analysis of the UAE extracts showed the presence of methyl 9,12 octadecadienoate (Z, Z)-, ethyl ester of hexadecanoic acid, ethyl octadec-9-enoate, and 1,4-diaza-2,5-dioxo-3-isobutyl bicyclo[4.3.0]nonane, which could be responsible for the antioxidant activity observed. This study was the first attempt to optimize the UAE parameters for the antioxidant compounds extraction from Diaporthe schini. UAE improved the extraction yield and reduced the extraction time in relation to HAE.

Improving the Recovery of Phenolic Compounds from Spent Coffee Grounds (SCG) by Environmentally Friendly Extraction Techniques.

The aim of this study was to investigate and compare the effects of different extraction techniques (high hydrostatic pressure-assisted extraction (HHPE), ultrasound-assisted extraction (UAE), and classical solvent extraction (CSE)) on phenolic compounds from spent coffee grounds (SCG). Different HHPE parameters (300, 400 and 500 MPa at 25 °C for 5, 10 and 15 min) and UAE parameters (40%, 50%, and 60% amplitude at 25 °C for 5, 10 and 15 min) were used. These techniques were compared with CSE (at 50 °C for 30 min) according to total phenolic content (TPC), antioxidant activity (AA), high-performance liquid chromatography (HPLC), scanning electron microscopy (SEM), and infrared (IR) spectroscopy. The results showed that eco-friendly techniques increased the TPC and AA compared to CSE and morphological changes were verified by SEM results. Furthermore, chlorogenic and caffeic acid were also quantified by using HPLC. Chlorogenic acid was found as the main phenolic compound in spent coffee grounds (SCG). The highest chlorogenic acid was detected as 85.0 ± 0.6 mg/kg FW with UAE at 60% amplitude for 15 min. In brief, for the extraction of phenolic compounds from waste SCG eco-friendly techniques such as HHPE and/or UAE were more convenient than CSE.