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The present investigation deals with the optimization of various parameters for extraction of oleoresins from Syzygium aromaticum (L.) Merr. and L.M. Perry buds (clove) using microwave assisted extraction (MAE) and ultrasound assisted extraction (UAE) by response surface methodology comparing the results with Soxhlet extraction (SE). The chemical composition of oleoresins was studied by GC-MS analysis. This was followed by testing their antibacterial potential against Escherichia coli, Yersinia enterocolitica, Staphylococcus aureus and Bacillus sp. and antioxidant potential. The maximum yield of clove oleoresin (COR) was obtained by UAE (42.00%) at 1:35 (solid to liquid ratio), 70°C for 12.50 min followed by SE (41.38%) and MAE (41.07%, 1:31 (solid to liquid ratio), 625 W for 60 s). The COR extracted by MAE showed the maximum percentage of various oxygenated terpenes (76.96%), followed by UAE (74.98%) and SE (44.92%). The major compound found in CORs extracted by MAE and UAE was eugenol acetate and for SE was 4,8,13-duvatriene-1,3-diol. The CORs extracted by MAE exhibited maximum antibacterial potential with minimum inhibitory concentration (MIC) which is the lowest COR concentration that inhibited the detectable growth of the test microorganisms in the range of 2.80–4.20 mg/ml followed by UAE (3.20–4.45 mg/ml) and SE (3.75–4.56 mg/ml). The COR extracted by MAE also exhibited maximum antioxidant activity against mustard oil degradation having the least increase in peroxide value, anisidine value, thiobarbituric acid value and total oxidation value after 28 days of storage. Hence, the maximum yield of COR was obtained by UAE but the maximum antibacterial and antioxidant potential was shown by COR extracted by MAE. Hence, COR extracted by MAE can be used as a natural food preservative as an alternative to synthetic food preservatives. [ABSTRACT FROM AUTHOR]

Significant attention is focused on mushrooms and mushroom protein hydrolysates owing to their sustainability and nutritional profile with different uses in diverse industries. This review examines the composition, functional properties, production methods and applications of mushroom protein hydrolysates. It commenced with a brief overview of protein hydrolysates where their importance and applications in food, pharmaceutical, cosmetic, and agricultural industries were explored. The significance of mushrooms as alternatives to animal proteins applicable to producing protein hydrolysates was discussed. Methods including conventional (chemical and enzymatic) extraction, ultrasound-assisted and microwave-assisted extractions used to extract proteins during protein hydrolysates production were discussed. Using enzyme-assisted-ultrasound-extraction to enhance protein extraction efficiency is exclusively highlighted as a promising technique. To obtain enhanced protein yield and quality, and protein hydrolysates with desired characteristics, crucial factors consisting of pH, temperature, extraction time, solvent type, enzyme concentration and ratio-of-substrate-concentration need to be optimized. The physicochemical and functional properties of mushroom protein hydrolysates are summarized. Variability of mushroom species, extraction efficiency, enzyme selection and cost, standardization, and consumer perception which constitute challenges and limitations for production and application of mushroom protein hydrolysates are addressed. Research should be conducted to optimize extraction and hydrolysis processes and explore new mushroom species.

IntroductionProcessing of Medicinal Aromatic Plants (MAPs) results in the production of a significant amount of by-products, which are not commercially exploitable. Towards this direction, we studied extensively the by-products of oregano and thyme, remaining after the aromatization of olive oils with microwave assisted extraction (MAE). The purpose of the study was the exploitation of the “wastes” of these two economically significant herbs of Greece, for the potential development of innovative bioactive products.MethodsHence, superior and inferior quality plant material from Origanum vulgare subsp. hirtum and Thymus vulgaris, were extracted with extra virgin olive oil using MAE. For the evaluation of raw plant material, beside the characterization of the essential oils (EOs), the hydroalcoholic extracts of superior and inferior plant material were afforded by ultrasound assistant extraction (UAE). In addition, the remaining plant material after the flavoring of olive oil by MAE, was extracted with c-Hex, MeOH, H2O:MeOH using UAE. All the extracts were evaluated for their DPPH free radical scavenging activity and total phenolic content (TPC) as well as their chemical profile was investigated by HPTLC. In parallel, the EOs, the olive oils and the c-Hex extracts were analyzed by GC–MS and Headspace Solid Phase Microextraction (HS-SPME)-GC–MS.Results and DiscussionThe results showed that the composition of the EOs and the volatile fraction of the olive oil extracts were similar for the superior quality material whereas for the inferior the composition of the volatile fraction of olive oil extracts was not analogous to the respective EOs. GC–MS analyses of oregano and thyme by-products revealed the presence of carvacrol, thymol, γ-terpinene and p-cymene among the major constituents. Moreover, the hydroalcoholic extracts obtained from the plant material remaining after olive oil flavoring with MAE showed similar phenolic content and scavenging activity with the hydroalcoholic extracts of the corresponding raw plant materials underlying their potent use in the preparation of high-added value products such as nutraceuticals and cosmeceuticals as well as enriched animal nutrition products.

Curcumin is one of the major constituents of turmeric which possess multifarious therapeutic properties. However, owing of its limited solubility in water its bioavailability is poor. Thus, attempts have been made to increase the solubility of curcumin by fermenting turmeric followed by extraction and encapsulation. Lactobacillus fermentum was used for the fermentation of raw turmeric pulp. The influence of Lactobacillus fermentation and different extraction methods (conventional solvent extraction (CSE), ultrasound (UAE) and microwave-assisted extraction (MAE)) on total phenolic content (TPC), flavonoid content, antioxidant activity and curcumin content were analyzed. Further, to increase the stability of extract, different concentrations of maltodextrin were used to microencapsulate the curcumin extract. The results showed that, Lactobacillus fermentation increased the TPC and antioxidant activity from 5.59 ± 0.20 to 6.27 ± 0.28 mg GAE/g and 67.49 ± 1.51 to 79.00 ± 2.20%, respectively. MAE showed highest TPC (7.88 ± 0.08 mg GAE/g), antioxidant activity (94 ± 1.57%) and curcumin content (0.866 ± 0.05 mg/g) followed by UAE and CSE. Maximum yield of curcumin extract was observed in MAE, UAE and CSE as 59.93, 47.09 and 29.44% respectively, higher than non-fermented turmeric pulp. Maltodextrin percentage showed a significant influence on bio-functional properties of encapsulated powder. However, 20% maltodextrin exhibited better bio-functional properties as compared to other concentrations. [ABSTRACT FROM AUTHOR]

Sitka spruce (Picea sitchensis) needles contain a variety of bioactive compounds including phenolic compounds and flavonoids, many of which have been used in the cosmetic, pharmaceutical, and food industries. This study aimed to investigate the effects of novel extraction techniques, including ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and simultaneous ultrasound-microwave-assisted extraction (UMAE) on the recovery of phenolic, flavonoids and associated antioxidant and anti-cancer properties from Sitka spruce (Picea sitchensis) needles. The ferric reducing antioxidant power (FRAP) assay was used to evaluate the antioxidant capacity, and the Alamar Blue assay using the human brain glioblastoma cancer cellline (U-251 MG) was used to evaluate the cytotoxicity activity. Results showed that US-probe accomplished the highest recovery of phenolic and flavonoids at 38 W cm-2 for 10 min (106.3 f 2.5 mg GAE g-1 DW and 63.2 i 3.8 mg QE g-1 DW, respectively). Hence, the highest cytotoxicity activity of IC5O (0.0114% w/v) was achieved by US-probe at 19 W cm-2 for 10 min. However, the antioxidant capacity of (2591.3 f 92.5 mM TE g-1 DUO was achieved under UMAE at ultrasound intensity of 38 W cm-2, microwave power of 302.4 W for 10 min. This study emphasised the potential application of UAE and MAE in the extraction of bioactive as an environmentally friendly method to be used in the valorisation of by-products in food and agro-industries. This supports the use of renewable natural resources in an efficient way to produce high-value compounds therefore it is in line with the new era of bioeconomy and its new biorefinery concepts. [ABSTRACT FROM AUTHOR]

The marine ecosystem provides resources for various food products and nutraceuticals with multiple benefits to human health. In this study, two underexploited seaweeds such as Sargassum polycystum (Sp) and Rosenvingea intricata (Ri) were used to investigate their biological potentials. The seaweeds underwent for washing and the washed water was examined to identify the bioactive compounds by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The fucoxanthin was extracted from both seaweeds using Ultrasound-Assisted Extraction (UAE) with 100% of absolute ethanol and acetone, which resulted in higher fucoxanthin from unwashed Ri (0.8 ± 0.12 mg/g) and unwashed Sp (0.59 ± 0.03 mg/g). Further, the remnant biomass of both washed and unwashed forms was used for the fucoidan extraction by employing UAE and Microwave-Assisted Extraction (MAE). Among these, the MAE process had yielded 1.86 folds higher fucoidan after fucoxanthin extraction from unwashed Sp compared to the washed. Finally, the relic seaweed residue of Sp underwent separate hydrolysis and batch fermentation (SHF) for the production of bioethanol, which was quantified by GC-MS. Thus, this study suggests that the entire biomass of seaweed would be a plausible feedstock for producing bioproducts. [Display omitted] • Decoding the various products garnered from S. polycystum and R. intricata. • Enhanced the yield of fucoxanthin from two seaweeds was achieved using UAE method. • Harnessing the remnant seaweed biomass for bioethanol production. [ABSTRACT FROM AUTHOR]

The unfavourable impacts of organic solvents on the environmental and human health have increasingly drawn the attention of scientists and technologists for a long run solution. Recently, ionic liquids (ILs) have emerged as an environmentally friendly alternative of choice to reduce the use of organic solvents. This review covers the data of literature published from 2011 to 2021. Literature search was performed for the relevant journal articles including books, and book chapters using the keywords of 'ionic liquid', 'extraction', 'medicinal plants', 'essential oil', 'waste water treatment', 'green extraction technology' and combination of them. ILs are designer solvents due to their modifiable properties according to the application conditions. Therefore, this review highlights the application of ILs in the extraction and purification of bioactive compounds (glycosides, phenolic compounds, flavonoids, alkaloids and others) and essential oils from plant materials. This includes the use of ILs in the microwave and ultrasound assisted extractions, as well as solid phase extraction. Previous studies reported about 20–35 % of increment in the yield of bioactive compounds with the use of ILs. • Literature review on articles reporting ionic liquids and their applications. • The applications of ionic liquids in the extraction of bioactive compounds and essential oils. • Ionic liquids as green solvent in various conventional and advanced extraction techniques. [ABSTRACT FROM AUTHOR]

Secondary metabolites from the sawmill waste Picea abies bark were extracted using an innovative two-step extraction that includes a first step with supercritical CO2 (SCO2) and a second step using green solvents, namely ethanol, water, and water ethanol mixture. Maceration (M), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) techniques were applied in the second step. A total of nineteen extract were obtained and yield were compared. Bark extracts were characterized by LC-DAD-MSn and classes of compounds were quantified as abietane derivatives, piceasides, flavonoids, and phenolics to compare different extractions. Obtained extracts were studied by in vitro assay to evaluate potential pharmaceutical, nutraceutical and cosmetic uses assessing the antioxidant activity as well as the inhibitory activity on target enzymes. Results show that the "smart extraction chain" is advantageous in term of yield of extraction and phytoconstituent concentration. SCO2 extract, presenting a unique composition with a large amount of abietane derivatives, exerted the best activity for amylase inhibition compared to the other extracts. [ABSTRACT FROM AUTHOR]

Secondary metabolites from the sawmill waste Picea abies bark were extracted using an innovative two-step extraction that includes a first step with supercritical CO2 (SCO2) and a second step using green solvents, namely ethanol, water, and water ethanol mixture. Maceration (M), ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) techniques were applied in the second step. A total of nineteen extract were obtained and yield were compared. Bark extracts were characterized by LC-DAD-MSn and classes of compounds were quantified as abietane derivatives, piceasides, flavonoids, and phenolics to compare different extractions. Obtained extracts were studied by in vitro assay to evaluate potential pharmaceutical, nutraceutical and cosmetic uses assessing the antioxidant activity as well as the inhibitory activity on target enzymes. Results show that the “smart extraction chain” is advantageous in term of yield of extraction and phytoconstituent concentration. SCO2 extract, presenting a unique composition with a large amount of abietane derivatives, exerted the best activity for amylase inhibition compared to the other extracts.

From the recent market trend, there is a huge demand for the bioactive compounds from various food matrices that could be capable enough to combat the emerging health effects in day-to-day life. Fenugreek is a well-known spice from ancient times for its medicinal and health benefits. In the present study, two methods of green extraction microwave (MAE) and ultrasound (UAE) assisted were studied in regard of extraction of fenugreek diosgenin. In this study, solvent type (acetone, ethanol, hexane and petroleum ether), solvent concentration (40, 60, 80 and 100%) and treatment time (1.5, 3.0, 4.5 and 6.0 min and 30, 40, 50 and 60 min for MAE and UAE method respectively) was varied to observe the effect of these parameters over extract yield and diosgenin content. The results of this study revealed that treatment time, type of solvent and its concentration and method adopted for extraction of diosgenin has significant effect. In relation with better yield extract and diosgenin content, the yield of fenugreek seed extract was 7.83% with MAE and 21.48% with UAE of fenugreek seed powder at 80% ethanol concentration at 6 and 60 min respectively. The content of diosgenin was observed in fenugreek seed powder extract was 35.50 mg/100 g in MAE and 40.37 mg/100 g in UAE with 80% ethanol concentration at 6 and 60 min respectively. The overall range of yield of fenugreek extract was varied from 1.04% to 32.48% and diosgenin content was 15.82 mg/100 g to 40.37 mg/100 g of fenugreek seed powder including both extraction methods. This study revealed that UAE would impose better ways for preparing fenugreek extract and observing diosgenin content from fenugreek seeds.

In this study, phenolic compounds were extracted from hawthorn fruit using microwave (MAE) and ultrasound assisted extraction (UAE) methods. The MAE was applied at different solids ratios, different extraction times and different microwave powers. UAE was applied at different solids ratios and sonication times. The maceration method was used as the control group. Total phenolic content (TPC) and color values of the extracts were examined. The highest values of TPC were determined as 9.31, 5.34, and 3.00 mg GAE/g dry matter in MAE, UAE, and maceration methods, respectively. Based on these results, it was found that the TPC value of the MAE method was 1.7 and 3.1-fold more than those of UAE and maceration, respectively. In addition, it was observed that L* values of MAE samples were lowest among others. It was concluded that the MAE is the most suitable method for the extraction of phenolic compounds from hawthorn fruit. [ABSTRACT FROM AUTHOR]

Phenolic compounds are broadly represented in plant kingdom, and their occurrence in easily accessible low-cost sources like wastes from agri-food processing have led in the last decade to an increase of interest in their recovery and further exploitation. Indeed, most of these compounds are endowed with beneficial properties to human health (e.g., in the prevention of cancer and cardiovascular diseases), that may be largely ascribed to their potent antioxidant and scavenging activity against reactive oxygen species generated in settings of oxidative stress and responsible for the onset of several inflammatory and degenerative diseases. Apart from their use as food supplements or as additives in functional foods, natural phenolic compounds have become increasingly attractive also from a technological point of view, due to their possible exploitation in materials science. Several extraction methodologies have been reported for the recovery of phenolic compounds from agri-food wastes mostly based on the use of organic solvents such as methanol, ethanol, or acetone. However, there is an increasing need for green and sustainable approaches leading to phenolic-rich extracts with low environmental impact. This review addresses the most promising and innovative methodologies for the recovery of functional phenolic compounds from waste materials that have appeared in the recent literature. In particular, extraction procedures based on the use of green technologies (supercritical fluid, microwaves, ultrasounds) as well as of green solvents such as deep eutectic solvents (DES) are surveyed.

Antibiotics are a group of drugs used for the treatment of bacterial diseases. They are used in both human and veterinary medicine and, although they are not permitted, they are sometimes used as growth promoters. The present research compares two extraction techniques: ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) in order to evaluate their efficiency in the determination of 17 usually prescribed antibiotics in human nails. The extraction parameters were optimized using multivariate techniques. Once both techniques were compared, MAE was selected as optimal due to its greater experimental practicability together with the better extraction efficiencies it provides. Target analytes were detected and quantified by ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). The run time was 20 min. The methodology was then successfully validated, obtaining acceptable analytical parameters according to the guide used. Limits of detection were between 0.3 and 3 ng g−1 and limits of quantification were in the range from 1.0 to 4.0 ng g−1. Recovery percentages ranged from 87.5% to 114.2%, and precision (in terms of standard deviation) was less than 15% in all cases. Finally, the optimized method was applied to nails taken from 10 volunteers and the results revealed the presence of one or more antibiotics in all the samples examined. The most commonly found antibiotic was sulfamethoxazole, followed by danofloxacin and levofloxacin. The results demonstrated, on the one hand, the presence of these compounds in the human body and, on the other hand, the suitability of nails as a non-invasive biomarker of exposure. [Display omitted] • UHPLC-MS/MS for the analysis of 17 antibiotics in human nail samples is proposed. • Two extraction techniques (MAE and UAE) are optimized and compared. • Multivariate experimental designs are used for sample treatment. • Amounts of antibiotics appear in the nail of volunteers untreated in the last 2 years. • Nails samples as a promising biomarker of exposure to these compounds. [ABSTRACT FROM AUTHOR]

Grape skins are one of the most important leftovers of grape juice production, and are also a good source of bioactive compounds, especially phenolic antioxidants and fiber, because they are not stressed as the winemaking process occurs. Their extracts may be used as functional components of enriched foods and beverage, both to color the products and to supplement with bio-functional metabolites. Therefore, in this work, ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) were optimized and compared using response surface methodology (RSM) and desirability function (D) statistical tools, at selected temperature and solvent type (close to 50 °C and water/ethanol/phosphoric acid 70:30:1) but varying contact time (t) and sample-to-solvent ratio (S/L), to find the best conditions for the extraction of the main polyphenols present in table grape skin (Apulia Rose cv.) residues from juice processing. The mathematical models built in this investigation showed that the highest significant factor (P < 0.001) was t, influencing the extraction of all compounds irrespective of the technique used, with the optimal results obtained at intermediate levels (10.5 and 21 min for MAE and UAE, respectively). On the contrary, the only S/L factor was not always significant, even though higher amount of polyphenols were generally recovered at low solid/liquid ratio (0.05 and 0.07 g/mL for MAE and UAE, respectively). Finally, UAE extracts exhibited higher content of anthocyanins, procyanidins, flavonols, and stilbenes than MAE, with values ranging from 1.5 to 69.6 mg/100 g of fresh weight. [ABSTRACT FROM AUTHOR]

Optimization process is an important aspect in the natural product extractions. Herein, an alternative approach is proposed for the optimization in extraction, namely, the Generalized Likelihood Uncertainty Estimation (GLUE). The approach combines the Latin hypercube sampling, the feasible range of independent variables, the Monte Carlo simulation, and the threshold criteria of response variables. The GLUE method is tested in three different techniques including the ultrasound, the microwave, and the supercritical CO 2 assisted extractions utilizing the data from previously published reports. The study found that this method can: provide more information on the combined effects of the independent variables on the response variables in the dotty plots; deal with unlimited number of independent and response variables; consider combined multiple threshold criteria, which is subjective depending on the target of the investigation for response variables; and provide a range of values with their distribution for the optimization. [ABSTRACT FROM AUTHOR]

The edible oil processing industry involves large losses of organic solvent into the atmosphere and long extraction times. In this work, fast and environmentally friendly alternatives for the production of echium oil using green solvents are proposed. Advanced extraction techniques such as Pressurized Liquid Extraction (PLE), Microwave Assisted Extraction (MAE) and Ultrasound Assisted Extraction (UAE) were evaluated to efficiently extract omega-3 rich oil from Echium plantagineum seeds. Extractions were performed with ethyl acetate, ethanol, water and ethanol:water to develop a hexane-free processing method. Optimal PLE conditions with ethanol at 150 °C during 10 min produced a very similar oil yield (31.2%) to Soxhlet using hexane for 8 h (31.3%). UAE optimized method with ethanol at mild conditions (55 °C) produced a high oil yield (29.1%). Consequently, advanced extraction techniques showed good lipid yields and furthermore, the produced echium oil had the same omega-3 fatty acid composition than traditionally extracted oil. [ABSTRACT FROM AUTHOR]

Several naturally derived food substances have now moved from territory of traditional and folklore medicines to rigorous studies aimed at identifying natural preventive therapies for disease. During chemical treatment bioactive substance can also be modified with possible negative impacts. Therefore safe and reliable extraction procedure should be improved and assessed. Because of growing interest in the extraction of bioactive compounds and nutraceuticals from plants and herbs and the search for sustainable extraction technique, MAE is fast realizing its promise as a technique that can respond to the rigorous demands this field necessitates. The traditional techniques of solvent extraction of plant materials require long extraction time and have low efficiency. Moreover, many natural products are thermally unstable and may degrade during thermal extraction. There are several novel techniques including ultrasound assisted extraction, microwave assisted extraction, supercritical fluid extraction and accelerated solvent extraction have been developed for the extraction of phytoconstituents from plants in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yield and enhance the quality of extracts. MAE has risen rapidly in the latest decade, and for most applications it has proven to be effective compared to traditional extraction techniques. The studies reported prove many advantages that make MAE an excellent substitute to traditional methods such as soxhlet and solid liquid extraction, as well as other environmentally benign technologies. Results also depicted that MAE coupled with high speed counter current chromatography is highly suitable technique for extraction, separation and purification. [ABSTRACT FROM AUTHOR]

The recovery of antioxidant polyphenols from light, dark and mix brewer’s spent grain (BSG) using conventional maceration, microwave and ultrasound assisted extraction was investigated. Total polyphenols were measured in the crude (60% acetone), liquor extracts (saponified with 0.75% NaOH) and in their acidified ethyl acetate (EtOAc) partitioned fractions both by spectrophotometry involving Folin−Ciocalteu reagent and liquid-chromatography-tandem mass spectrometry (LC-MS/MS) methods. Irrespective of the extraction methods used, saponification of BSG yielded higher polyphenols than in the crude extracts. The EtOAc fractionations yielded the highest total phenolic content (TPC) ranging from 3.01 ± 0.19 to 4.71 ± 0.28 mg gallic acid equivalent per g of BSG dry weight. The corresponding total polyphenols quantified by LC-MS/MS ranged from 549.9 ± 41.5 to 2741.1 ± 5.2 µg/g of BSG dry weight. Microwave and ultrasound with the parameters and equipment used did not improve the total polyphenol yield when compared to the conventional maceration method. Furthermore, the spectrophotometric quantification of the liquors overestimated the TPC, while the LC-MS/MS quantification gave a closer representation of the total polyphenols in all the extracts. The total polyphenols were in the following order in the EtOAc fractions: BSG light > BSG Mix > BSG dark, and thus suggested BSG light as a sustainable, low cost source of natural antioxidants that may be tapped for applications in food and phytopharmaceutical industries.

Phenolic compounds were extracted from the husk of milled black rice (cv. Poireton) by using a combination of ultrasound assisted extraction and microwave assisted extraction. Extraction parameters were optimized by response surface methodology according to a three levels, five variables Box-Behnken design. The appropriate process variables (extraction temperature and extraction time) to maximize the ethanolic extraction of total phenolic compounds, flavonoids, anthocyanins and antioxidant activity of the extracts were obtained. Extraction of functional components with varying ethanol concentration and microwave time were significantly affected by the process variables. The best possible conditions obtained by RSM for all the factors included 10.02 min sonication time, 49.46 °C sonication temperature, 1:40.79 (w/v) solute solvent ratio, 67.34% ethanol concentration, and 31.11 s microwave time. Under the given solutions, the maximum extraction of phenolics (1.65 mg/g GAE), flavonoids (3.04 mg/100 g), anthocyanins (3.39 mg/100 g) and antioxidants (100%) were predicted, while the experimental values included 1.72 mg/g GAE of total phenolics, 3.01 mg/100 g of flavonoids, 3.36 mg/100 g of anthocyanins and 100% antioxidant activity. The overall results indicated positive impact of co-application of microwave and ultrasound assisted extractions of phenolic compounds from black rice husk. [ABSTRACT FROM AUTHOR]

Extraction is an important method for analytical and industrial applications. The studies related to this subject mostly focus on the extraction of compounds such as anthocyanins, phenolic compounds which can be used for the production of functional foods. It is important to protect not only the extracted compounds from the adverse effects of extraction but also the environment by employing green extraction techniques. Hence, new technologies are being developed and studies are being conducted with different foods. Recently, it is aimed to reduce the solvent consumption and extraction time by employing new green extraction methods which are developed as alternatives to conventional methods. This article reviews the most commonly employed green extraction methods (microwave, ultrasound, high pressure, pulsed electric field, ohmic and supercritical fluid extraction) by focusing on the principals, advantages and applications of the new methods. [ABSTRACT FROM AUTHOR]

Efficiency of conventional solvent extraction (maceration and normal refluxing) and novel extraction techniques (ultrasound-assisted extraction-UAE and microwave-assisted extraction-MAE) were compared in order to obtain an enhanced content of total flavonoid, total phenolic compounds and rosmarinic acid from the Satureja hortensis L. (Summer savory) herb. Different mixtures of ethanol-water ratio were used for extraction of these compounds from dry plant material. High level of total flavonoid content was determined for a solvent system consisted of 40% respectively 50% ethanol (extraction systems ES6 and ES5) while the most efficient techniques were normal refluxing (R) and ultrasound-assisted extraction when sweep mode (UAE1) was selected. For the same solvent systems (ES6 and ES5), a high content of total phenolic compounds was determined when the normal refluxing (R) and microwave-assisted extraction (MAE1, with a duty coefficient of 40% and microwave action time1 min) were used for the extraction procedure. For the rosmarinic acid extraction, the maceration technique (M) combined with an ethanol-water system consisted of 60% ethanol (ES4) was found as the most efficient procedure. [ABSTRACT FROM AUTHOR]

Alkaloids are a chemically diverse group of natural products known for their pharmacological and toxicological effects. Plants are the best known source of these compounds. Because of their high complexity, herbal matrices must be properly processed in order to access alkaloid content, overcoming different analytical steps, such as sampling, sample preparation, isolation, quantification and data analysis. Notably, sample preparation just recently is calling the attention, being considered a bottleneck of analytical processes. In this review, we provide the current state of the art in sample preparation for alkaloids analysis in herbal matrices, focusing on both extraction and clean-up steps. Both classic and modern techniques, such as Negative-Pressure Cavitation Extraction (NPCE), Microwave Assisted Extraction (MAE), as well as microfluidic chips are addressed, including the technique fundamentals, factors to be optimized, and their applications. A general discussion is also given, pointing out the advantages and limitations of each technique. [ABSTRACT FROM AUTHOR]

In this study, Pistacia lentiscus var. chia leaves were dehydrated by freeze drying and the initial, final moisture content and the drying kinetics were examined. Soxhlet Extraction (SE), Microwave Assisted (MAE) and Ultrasound Assisted Extraction (UAE) were employed to recover extracts with high antioxidant activity, total phenolic and flavonoid content from fresh and dried leaves. Fresh leaves showed higher yield and antioxidant potential, with MAE extracts exhibiting the greatest extraction yield (48.11 ± 0.56% d.b.), followed by UAE (39.39 ± 1.13% d.b.) and SE (31.99 ± 1.55% d.b.). UAE extracts exhibited the highest antioxidant activity (IC 50 = 37.13 ± 2.7 μg/mL), while SE extracts showed the highest total phenolic content (314.88 ± 0.01 mg GAE/g dry extract). UAE extracts of dried leaves exhibited total flavonoid content (106.5 ± 0.02 mg QE/g dry extract). Moreover, UHPLC-ESI–HMRS was performed to the extract with the highest antioxidant activity and confirmed the presence of isomers of galloyl quinic acid, quercetin and kaempferol glucosides, luteolin and neorehmannioside. [ABSTRACT FROM AUTHOR]

In this study, multifunctional extracts from Dunaliella salina microalga and Daucus carota carrots have been suggested as food additives since they are rich in B-carotene, a widely used coloring and antioxidant agent. A comparative analysis between conventional solvent extraction and innovative green extraction methods, using microwaves and ultrasounds, has been conducted. The isolation of b-carotene, as well as, the environmental impact of each method, were the criteria for the processes evaluation. In order to evaluate the selected extraction processes’ sustainability, a comparative life cycle analysis was carried out from farm/cultivation to recovery process, using proper databases and software. The comparative analysis for both matrices revealed that the cultivation and harvesting of D. salina in open ponds exhibits an overall environmental impact greater than of the carrots farming. Nonetheless, D. salina ‘s high content in β-carotene leads to higher extraction yields and therefore to extraction processes with lower impact. UAE is the indicated extraction technique for the sustainable recovery of β-carotene from microalgae. This study is a laboratory-scale application with potential scale up practice for nutraceutical, cosmetic and food industries. [ABSTRACT FROM AUTHOR]

In this study, Agiorgitico red grape pomace byproducts were dehydrated by air drying and accelerated solar drying and sequentially extracted by three different extraction methods using water, water:ethanol (1:1) and ethanol as solvents. The methods include microwave assisted (MAE) and ultrasound assisted extraction (UAE) and the conventional Soxhlet extraction (SE). The efficiency and selectivity of drying and extraction processes were determined in terms of extraction yield, antiradical activity ( A AR ) and total phenolic content (TPC). UAE water:ethanol extracts were found to be rich in phenolic compounds (up to 438984 ± 4034 ppm GAE in dry extract) with high A AR (0.36 ± 0.01 to 0.91 ± 0.02 mg/mL) and therefore were analysed using HPLC-DAD-ESI-MS/MS and DMACA assay. The profile of anthocyanins, flavonols and flavan-3-ols were significantly affected ( p < 0.05) by the drying procedure. Air dried grape pomace extracts exhibited the highest total flavan-3-ol (43469 ± 1210 ppm CE), total anthocyanin (34188 ± 362 ppm Mv-3-glc eq.) and total flavonol (4484 ± 108 ppm QE) content. [ABSTRACT FROM AUTHOR]

Present study deals with the microwave assisted extraction (MAE) of ursolic acid (UA) and oleanolic acid (OA) from Ocimum sanctum leaves. UA and OA have been reported to possess significant medicinal properties. Various experimental parameters such as selection of solvent, solvent composition, irradiation time, microwave power, solid to solvent ratio, preleaching time and number of cycles were investigated to optimize the extraction process. Under optimum conditions of irradiation time (3 min), microwave power (272 W), solid to solvent ratio (1:30), preleaching time (10 min), maximum UA and OA has been extracted in one extraction cycle with ethanol: water (80:20) as a solvent. Maximum 86.76 and 89.64% of UA and OA was extracted under above mentioned optimized experimental conditions. MAE was also compared with the batch and ultrasound assisted extraction (UAE) method. As compared to batch and UAE, higher extraction yield of these important phytochemicals have been obtained through MAE in only 3 min. [ABSTRACT FROM AUTHOR]

Highlights: [•] Microwave and ultrasound-assisted extraction of phenolic compounds from C. limon peels were compared. [•] Response surface methodology successfully employed to optimize the extraction processes. [•] Better performance of microwave extraction than both ultrasound and conventional process. [Copyright &y& Elsevier]

Abstract: The use of natural antioxidants in the food industry has increased in the last years and there is a growing interest in improving the extraction processes using GRAS (general recognize as safe) solvents. In this work the extraction of antioxidants from rosemary with ethanol and water as solvents has been studied using different extraction processes (conventional, microwave assisted – MAE – and ultrasound assisted – USAE –) and plant pretreatments (deoiled and milled, deoiled and fresh plant). Total phenolic compounds in the extracts were determined by the Folin–Ciocalteu assay and HPLC with UV detection was employed for the quantitation of the main antioxidant compounds: rosmarinic acid and carnosic acid. The antioxidant activity of the extract was determined by the DPPH scavenging assay. The double pretreatment, deoiling by solvent free microwave extraction (SFME) and milling, has shown to be essential to overcome inner mass transfer limitations. Extraction efficiency can be additionally enhanced by microwave and ultrasound assisted extraction process, being this latter more significant in aqueous extracts. [Copyright &y& Elsevier]

In recent years, substantial research has been devoted to the development of new liquid-liquid microextraction methods for sample preparation. These microextration methods were performed by several techniques such as: liquid-phase microextraction (LPME) or membrane-assisted solvent extraction (MASE), hollow fiber liquid phase microextraction (HF-LPME), single drop-phase microextraction (SDME), liquid-liquid-liquid-microextraction (LLLME), dispersive liquid-liquid microextraction (DLLME), and ionic liquid dispersive liquid-liquid microextraction (IL-DLLM). For performance extraction, increasing the ultrasound field utilized techniques such as: ultrasound-asisted liquid phase microextraction (ULPME), ultrasound-asisted ionic liquid dispersive liquid-phase microextraction (UILDLPM), ultrasound-asisted dispersive liquid-liquid microextraction (UDLLME), and ultrasound-asisted headspace liquid-phase microextraction (UHS-LPME) for extraction from a complex matrix. Also, microwave field was used for solid sample preparation improvement. Other techniques such as solid phase extraction (SPE), solid phase microextraction (SPME,) and stir bar solvent extraction (SBSE) were frequently used in liquid sample preparation. The bests results were obtained after careful optimization. [ABSTRACT FROM AUTHOR]

Crypthecodinium cohnii represents a heterotrophic microalga rich in omega-3 polyunsaturated fatty acids (PUFAs) with significant health benefits, and especially docosahexaenoic acid (DHA). In the present study, freeze-dried C. cohnii biomass, cultivated in fed-batch bioreactors with a feed of acetic acid 33% (v /v), was used. In the first set of experiments, ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE) were employed with the aim of discovering the most efficient technique regarding the recovery of DHA. Organic and food grade solvents were used, namely n-hexane, 2-2-butanol and n-hexane: isopropanol (2:3), under specific conditions. Extraction yields (EYs) were calculated and PUFAs content was evaluated through Gas Chromatography (GC). UAE using n-hexane: isopropanol (2:3) and 2-butanol presented the highest yields and were further examined in the second set of experiments in order to optimize the recovery of DHA, while changing the extraction time and the ultrasound power. Enzymatic Hydrolysis (EH) was also applied using four enzyme preparations, three concentrations of C. cohnii biomass and n-hexane: isopropanol (2:3) as solvent. In addition, homogenisation assisted extraction in microemulsion (HAE) was studied while changing the solvent, time and rotation speed. Simple mathematical models were applied in order to correlate the EY with the applied conditions for every extraction method. Parameters screening during UAE demonstrated that the best extraction time was 15 min, reaching the yield of 26.17% and total fatty acids (TFAs) content of 261.75 mg/g dry weight (DW). Among all used extraction techniques, UAE recovered maximum quantities of TFAs, while HAE was proven the most efficient regarding DHA content (131.20 mg/g DW). In conclusion, the proposed green extraction methods were found to be attractive for the recovery of PUFAs from C. cohnii. • Ultrasound Assisted Extraction (UAE) recovers maximum quantities of total lipids. • Homogenisation Assisted Extraction (HAE) obtains maximum docosahexaenoic acid (DHA). • n-Hexane: isopropanol (2:3) solvent system succeed the richest lipid amounts. • The longest extraction times achieve the highest yields. [ABSTRACT FROM AUTHOR]

• Diosgenin extraction from Trigonella foenum graecum seeds. • Analyzing better extract yield and diosgenin content from both methods. • Both yield of extract and diosgenin content is higher with ultrasound than microwave assisted extraction methods. From the recent market trend, there is a huge demand for the bioactive compounds from various food matrices that could be capable enough to combat the emerging health effects in day-to-day life. Fenugreek is a well-known spice from ancient times for its medicinal and health benefits. In the present study, two methods of green extraction microwave (MAE) and ultrasound (UAE) assisted were studied in regard of extraction of fenugreek diosgenin. In this study, solvent type (acetone, ethanol, hexane and petroleum ether), solvent concentration (40, 60, 80 and 100%) and treatment time (1.5, 3.0, 4.5 and 6.0 min and 30, 40, 50 and 60 min for MAE and UAE method respectively) was varied to observe the effect of these parameters over extract yield and diosgenin content. The results of this study revealed that treatment time, type of solvent and its concentration and method adopted for extraction of diosgenin has significant effect. In relation with better yield extract and diosgenin content, the yield of fenugreek seed extract was 7.83% with MAE and 21.48% with UAE of fenugreek seed powder at 80% ethanol concentration at 6 and 60 min respectively. The content of diosgenin was observed in fenugreek seed powder extract was 35.50 mg/100 g in MAE and 40.37 mg/100 g in UAE with 80% ethanol concentration at 6 and 60 min respectively. The overall range of yield of fenugreek extract was varied from 1.04% to 32.48% and diosgenin content was 15.82 mg/100 g to 40.37 mg/100 g of fenugreek seed powder including both extraction methods. This study revealed that UAE would impose better ways for preparing fenugreek extract and observing diosgenin content from fenugreek seeds. [ABSTRACT FROM AUTHOR]

It's a well-known fact that bitter gourd seed oil is a rich source of α-eleostearic acid that have positive effects on breast cancer, diabetes and coronary artery diseases. The conventional methods of oil extraction often lead to a lower yield and consumes more time. This study was carried out by using three different process intensification tools such as ultrasound assisted extraction (USAE); microwave assisted extraction (MWAE) and ohmic assisted extraction (OHAE) at different power level and solid to liquid ratio. P -cymene was used as a green solvent for extraction and Peleg's model was adopted to describe the kinetics of extraction process. The highest yield of 27.42% for USAE, 30.42% for MWAE and 25.34% for OHAE was observed. In addition, USAE extracted oil was better in quality aspects. The extracted oil mainly composed of poly-unsaturated fatty acids; α-eleostearic, linolenic acid, gamma linolenic acid and stearic acid. Among all the treatments, USAE gave best quality of oil with highest percentage of alpha-eleostearic (6.51%), linolenic acid (6.24%) and stearic acid (0.80%). The present study indicates that USAE and use of p -cymene serves as a potential sustainable approach for edible oil production without imposing environmental burden. Image 1 • An emerging technology approach for extraction of oil from Bitter gourd seeds. • Peleg's model can explain the extraction kinetics of oil using emergent technologies. • Ultrasound assisted extraction gave the best quality oil. [ABSTRACT FROM AUTHOR]

• Novel technologies for improved extraction yields of hydrocolloids. • Clean and green innovative approaches for hydrocolloids are reviewed. • Synergistic combinations of novel and/or conventional technologies are reviewed. • Challenges associated with industrial scale up of technologies. The macroalgal hydrocolloid industry is a rapidly growing industry with an annual growth in the global production of 2–3 %. Hydrocolloids from macroalgae are mainly in the form of polysaccharides with other nutrients, such as vitamins, minerals, and proteins. Due to its potential industrial applications, macroalgae have been used as raw materials for hydrocolloids extraction. Compared to the conventional extraction methods, emerging innovative assisted extraction technologies (e.g., Ultrasound/Microwave assisted extraction) have been developed to maximise the extraction yields, efficiency and thereby, maintaining sustainability along the process. These novel techniques are considered as clean and green strategies, with a potential for a large-scale production; thus, avoiding or reducing the use of chemicals. However, more research is required to establish their mechanism of action in order to finally implement them at industrial level. This paper reviews the most relevant strategies and technologies involved in the production of hydrocolloids from macroalgae. [ABSTRACT FROM AUTHOR]

In this study, the recovery of polyphenols from olive oil mill and winery waste was investigated. The performance of ultrasound assisted extraction (UAE), microwave assisted extraction (MAE), and pressurized liquid extraction (PLE) was assessed using ethanol–water mixtures, which are compatible with food, nutraceutical, and cosmetic applications. The extraction efficiency from olive pomace and lees samples was evaluated in terms of total polyphenol content (TPC), determined by high performance liquid chromatography (HPLC) and Folin–Ciocalteu assay. The effect of solvent composition, temperature, and time was analyzed by response surface methodology. Ethanol:water 50:50 (v/v) was found to be a suitable solvent mixture for both kinds of samples and all three extraction techniques. The performance of the extraction techniques was evaluated, under optimal experimental conditions, with a set of different representative samples of residues from olive oil and wine production. Overall, the best extraction efficiency for olive pomace residues was provided by MAE (ethanol:water 50:50 (v/v), 90 °C, 5 min), and for wine residues by PLE (ethanol:water 50:50 (v/v), 100 °C, 5 min, 1 cycle). However, the results provided by UAE (ethanol:water 50:50 (v/v), 30 min) were also suitable. Considering not only extraction performance, but also investment and operational costs, UAE is proposed for a future scaling up evaluation. Regarding olive pomace as a source for natural phenolic antioxidants, olive variety and climatic conditions should be taken into account, since both influence TPC in the extracts, while for winery residues, lees from red wines are more suitable than those from white wines. [ABSTRACT FROM AUTHOR]

The recovery of antioxidant polyphenols from light, dark and mix brewer's spent grain (BSG) using conventional maceration, microwave and ultrasound assisted extraction was investigated. Total polyphenols were measured in the crude (60% acetone), liquor extracts (saponified with 0.75% NaOH) and in their acidified ethyl acetate (EtOAc) partitioned fractions both by spectrophotometry involving Folin–Ciocalteu reagent and liquid-chromatography-tandem mass spectrometry (LC-MS/MS) methods. Irrespective of the extraction methods used, saponification of BSG yielded higher polyphenols than in the crude extracts. The EtOAc fractionations yielded the highest total phenolic content (TPC) ranging from 3.01 ± 0.19 to 4.71 ± 0.28 mg gallic acid equivalent per g of BSG dry weight. The corresponding total polyphenols quantified by LC-MS/MS ranged from 549.9 ± 41.5 to 2741.1 ± 5.2 µg/g of BSG dry weight. Microwave and ultrasound with the parameters and equipment used did not improve the total polyphenol yield when compared to the conventional maceration method. Furthermore, the spectrophotometric quantification of the liquors overestimated the TPC, while the LC-MS/MS quantification gave a closer representation of the total polyphenols in all the extracts. The total polyphenols were in the following order in the EtOAc fractions: BSG light > BSG Mix > BSG dark, and thus suggested BSG light as a sustainable, low cost source of natural antioxidants that may be tapped for applications in food and phytopharmaceutical industries. [ABSTRACT FROM AUTHOR]