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White tea is valuable for having a high antioxidant content, which is considered to possess numerous beneficial effects on health. This study investigated the application of microwave-assisted extraction (MAE) for the extraction of total phenolic compounds from white tea. The experimental setup included four independent variables: microwave power (ranging from 100 to 300 W), extraction time (ranging from 10 to 40 min), temperature (ranging from 35 to 50 °C), and the ratio of food to solvent (ranging from 0.25 to 0.5 g/10 mL). The responses that were evaluated were IC50 (ppm) and total phenolic content (mg/g). The experimental design consisted of thirty runs conducted within the MAE system. The group method of data handling (GMDH) models were used to predict important efficiency measures (IC50 and total phenol content) in the extraction process. The models were assessed based on their ability to capture the relationships between input conditions and efficiency outputs. Three GMDH variants were compared: baseline GMDH, GMDH optimized with a genetic algorithm (GMDH-GA), and GMDH optimized with a harmony search algorithm (GMDH-HS). While all models achieved high predictive ability on a test set, GMDH-HS emerged as the superior performer. It achieved near-perfect agreement with observations (d-index > 0.998), minimal errors (NRMSE < 0.02), and effectively captured data variance (NSE > 0.99) for both outputs. Correlation diagrams and Taylor diagrams confirmed the superior performance of GMDH-HS in terms of linearity, correlation, and error minimization. This study demonstrates the effectiveness of hybridizing GMDH with a harmony search algorithm for complex modeling tasks, paving the way for improved efficiency and yield optimization in extraction processes. [ABSTRACT FROM AUTHOR]

The process of removing sulfur compounds and aromatic compounds to produce clean fuel is an important and effective contribution to the processes of mitigating and adapting to climate change. In contrast, it is necessary to find an innovative way to remove sulfur and carcinogenic aromatic compounds because clean, low-sulfur diesel is commonly used in all countries of the world at the present time. Therefore, in this work, we have studied the effect of the microwave radiation power and the irradiation time with the use of more than one type of organic solvent; methanol, acetonitrile and ethyl acetoacetate; as an extractant and solvent to feed ratio impact on the removal of sulfur and aromatic compounds of a real diesel fuel feed which has 450 ppm sulfur content and 16 wt% aromatic Content. The results showed that the best solvent used during this work was ethyl acetoacetate. According to the results, high sulfur removal (≈ 92%) was accomplished with microwave-assisted extractive desulfurization technique under the following ideal conditions: the irradiation time is 7 min, the solvent feed ratio is 3:1 and the microwave intensity is 180 W. To reveal the mechanism of microwave-assisted extractive desulfurization via different organic solvents, a theoretical study including structural examination and interaction energy analysis on the interaction between dibenzothiophene (DBT) or dimethyl dibenzothiophene (DMDBT) and the different organic solvents was also conducted. [ABSTRACT FROM AUTHOR]

Oranges dominate the world in terms of harvested area, with an annual global production of 60 million tonnes. Approximately 40–50% of orange production is utilized for fruit processing. Notably, the peel waste generated from juice processing industries exceeds 32 million tonnes. Most of the waste generated is either disposed of in landfills or thrown into rivers, leading to water contamination and elevated pollution rates. Factors contributing to this include low pH, high water and organic content, ease of fermentability, and substantial demand for oxygen. The orange peel is rich in bioactives, providing protection against a range of diseases. Both traditional and non-conventional extraction methods, are available to extract these bioactives. Traditional methods come with various limitations, meanwhile, the non-conventional green extraction methods like microwave assisted extraction (MAE), supercritical fluid extraction (SFE), ultrasound assisted extraction (UAE), pulse electric field extraction (PEF), enzyme-assisted extraction (EAE), etc., are becoming more significant because of their no thermal nature and environmentally beneficial characteristics. Moreover, green extraction methods employ reduced amounts of solvents, consume less energy, require shorter extraction time, yield higher extraction rate, and are environmentally friendly. This review compiles the effective utilization of orange peel for the bioactive recovery, sources, properties and novel extraction techniques. [ABSTRACT FROM AUTHOR]

Abstract White tea is valuable for having a high antioxidant content, which is considered to possess numerous beneficial effects on health. This study investigated the application of microwave-assisted extraction (MAE) for the extraction of total phenolic compounds from white tea. The experimental setup included four independent variables: microwave power (ranging from 100 to 300 W), extraction time (ranging from 10 to 40 min), temperature (ranging from 35 to 50 °C), and the ratio of food to solvent (ranging from 0.25 to 0.5 g/10 mL). The responses that were evaluated were IC50 (ppm) and total phenolic content (mg/g). The experimental design consisted of thirty runs conducted within the MAE system. The group method of data handling (GMDH) models were used to predict important efficiency measures (IC50 and total phenol content) in the extraction process. The models were assessed based on their ability to capture the relationships between input conditions and efficiency outputs. Three GMDH variants were compared: baseline GMDH, GMDH optimized with a genetic algorithm (GMDH-GA), and GMDH optimized with a harmony search algorithm (GMDH-HS). While all models achieved high predictive ability on a test set, GMDH-HS emerged as the superior performer. It achieved near-perfect agreement with observations (d-index > 0.998), minimal errors (NRMSE 0.99) for both outputs. Correlation diagrams and Taylor diagrams confirmed the superior performance of GMDH-HS in terms of linearity, correlation, and error minimization. This study demonstrates the effectiveness of hybridizing GMDH with a harmony search algorithm for complex modeling tasks, paving the way for improved efficiency and yield optimization in extraction processes.

Abstract The process of removing sulfur compounds and aromatic compounds to produce clean fuel is an important and effective contribution to the processes of mitigating and adapting to climate change. In contrast, it is necessary to find an innovative way to remove sulfur and carcinogenic aromatic compounds because clean, low-sulfur diesel is commonly used in all countries of the world at the present time. Therefore, in this work, we have studied the effect of the microwave radiation power and the irradiation time with the use of more than one type of organic solvent; methanol, acetonitrile and ethyl acetoacetate; as an extractant and solvent to feed ratio impact on the removal of sulfur and aromatic compounds of a real diesel fuel feed which has 450 ppm sulfur content and 16 wt% aromatic Content. The results showed that the best solvent used during this work was ethyl acetoacetate. According to the results, high sulfur removal (≈ 92%) was accomplished with microwave-assisted extractive desulfurization technique under the following ideal conditions: the irradiation time is 7 min, the solvent feed ratio is 3:1 and the microwave intensity is 180 W. To reveal the mechanism of microwave-assisted extractive desulfurization via different organic solvents, a theoretical study including structural examination and interaction energy analysis on the interaction between dibenzothiophene (DBT) or dimethyl dibenzothiophene (DMDBT) and the different organic solvents was also conducted.

Huge amount of waste is generated by the pineapple processing industries which raises concerns regarding its safe disposal into the environment. This ever-increasing problem of waste management can be solved by the valorization of pineapple by-products to high-value compounds. The extraction of proteolytic enzyme, bromelain from pineapple rind using green techniques can help to overcome the drawbacks associated with conventional methods. In the present study, the extraction of bromelain from pineapple rind using microwave assisted technique resulted in considerable amount of proteolytic activity (127.8 U/mL) and protein content (2.55 mg/mL). The optimized extraction conditions were found as 200 W microwave power, 1:5 solid/ liquid ratio and after treatment time of 10 min. Highest specific activity (512 U/mg) of bromelain was obtained after using gel filtration chromatography. FTIR result confirmed the presence of functional groups in bromelain, whereas, XRD analysis indicated the semi-crystalline nature of bromelain. The results indicated MAE as an effective green technique for the extraction of bromelain from pineapple rind. The proteolytic action of the extracted bromelain makes it a suitable functional ingredient for its applications in bakery, dairy, and seafood processing industries. [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.

Abstract The study aimed to optimize microwave-assisted extraction (MAE) of phenolics from gilaburu fruit (GF) with the response surface method (RSM). GF was used to produce two functional products: The first one was encapsulated hydrogel beads GF (eGF) using ionic gelation and chitosan system, and the second one was a sugar-free functional beverage (FB) enriched with black carrot, riboflavin, and ascorbic acid. The optimal extraction conditions were determined to be 60 °C for temperature, 5 minutes for time, and 4.18 g/100 mL for solid/solvent ratio based on the highest total phenolic content (TPC) and extraction yield. The model was found to be sufficient for the successful prediction of experimental results. Chlorogenic acid was a major compound of GF, eGF, and sugar-free FB. The inhibition of α-glucosidase activity (%) for GF, eGF, and sugar-free FB was detected as 54, 92, and 77, respectively. These findings revealed that utilizing MAE may shorten the extraction of GF phenolics with low energy and maximum efficiency. Furthermore, GF, eGF, and sugar-free FB have promising antioxidant and antidiabetic activities due to their rich bioactive and fortified compounds. They may be regarded excellent sources of compounds for the functional food industry. Besides, they can be used to provide health benefits to diabetic patients and future consumers.

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]

Globally, approximately 2 billion tons of agricultural waste is generated each year which is rich reservoirs of bioactive compounds. Therefore, it has become increasingly important to manage and treat waste in an environmentally, economically, and socially responsible manner. These compounds can be extracted without altering their properties through the utilization of deep eutectic solvents (DES). Given their exceptional qualities aligning with green chemistry principles, DESs possess significant promise in supplanting conventional organic solvents and ionic liquids (IL). This is owing to natural deep eutectic solvents (NADES) unique physicochemical properties, which include its low toxicity, biodegradability, and biological activity. Meanwhile, conjugating DES using non-conventional extraction techniques such as microwave-assisted extraction (MAE) may reduce extraction times, increase yields, and be more environmentally friendly. The purpose of this study is to give a thorough understanding of valorization of agro-industrial food wastes by extraction of phenolic compounds using green solvents. Specifically, the research concentrates on investigating the physicochemical attributes of NADES and their synergy with the MAE method to retrieve phenolic compounds. Additionally, discussion encompassed the impact of MAE and NADES on the antioxidant, antimicrobial, and other health-promoting properties of bioactive compounds. In conclusion, the results demonstrated the feasibility of using these emerging solvents with MAE for the extraction process. Further, proper elucidation of the extraction mechanisms involved is necessary in order to expand the applications of these emerging solvents for bioactive compound recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microwave-assisted-glycerol deep eutectic solvent was employed for the extraction of phytochemicals from the C. intybus. • The efficiency was evaluated based on TTC, TPC, TFC and DPPH radical scavenging activity. • At optimum conditions, the glycerol deep eutectic solvent showed promising efficiency. • This solvent system could be used for bioactive extraction on a larger scale. In this study, glycerol-based deep eutectic solvent system was employed for optimized extraction of valuable phytochemicals from the Cichorium intybus plant. Microwave assisted-glycerol based deep eutectic solvent extraction technique (MAE-G DES) was optimized with response surface methodology (RSM) with glycerol/sodium acetate DES as extracting solvent. The responses include total tannin content (TTC), total phenolic content (TPC), total flavonoid content (TFC) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (DRSA). The results showed well fitted models as linear model for TPC and quadratic model for TTC, TFC and DRSA. The optimized conditions were found to be 315 W (microwave power), 2 min (extraction time), and 34 mL/g (solvents to sample ratio) with optimum TTC as 1.289 mg TAE/g dry weight (DW), TPC as 401.55 mg GAE/100 g DW, TFC as 135.64 mg RE/100 g DW and DRSA of 19.24 mg AAE/g of DW. Furthermore, the optimized MAE-G DES extract was screened for antidiabetic potential and the results showed 46.76 ± 2.03 % inhibition against α-glucosidase and 21.35 ± 0.22 % α-amylase inhibitory activity compared to standard acarbose as 43.97 ± 1.54 % and 39.46 ± 2.10 % inhibition against α-glucosidase and α-amylase enzymes, respectively at a concentration of 10 mg/mL. It is concluded by this work that glycerol/sodium-acetate based deep eutectic solvents could be used as an alternative and effective solvent for the extraction of tannins and other pharmaceutically significant phytochemicals from Chicorium intybus on a larger scale. [ABSTRACT FROM AUTHOR]

Introduction: Processing 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., Methods: Hence, 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, H 2 O: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 Discussion: The 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., Competing Interests: DK and ID were employed by Pellas Nature S.A. and PB was employed by Bagatzounis & Sons S.A. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Dina, Cheilari, Vontzalidou, Karamani, Diamanti, Bagatzounis, Giannenas, Grigoriadou and Aligiannis.)

Microwave hydrothermal treatment was selected to extract valuable fractions with bioactive and gelling properties from Evernia prunastri lichen with potential for topical applications. The impact of the extraction processing conditions on the soluble extracts, mucilage fraction and residual solid phase was analyzed within a lichen global valorization approach. A particular stress was made on the thermo-rheological and structural characteristics of the extracted glucan and galactomannan polymers, the corresponding gelled matrices, and their cosmetic feasibility. Results revealed that the proposed microwave-assisted treatment showed a relevant influence on the phytochemical features of the aqueous soluble extracts, accounting the major protein content at 120 °C and the enhanced antioxidant and anti-tyrosinase properties at 140 °C. Extracts at 200 °C showed the highest anti-inflammatory (COX-1 and COX-2 inhibition) efficacies. The biopolymer analyses indicated that those recovered after lichen hydrothermal treatment at 160 °C featured a good extraction performance, the highest molecular weight, apparent viscosity, and antiproliferative potential. The thermo-rheological properties of the corresponding matrices formulated at 10 % and 60 or 80 °C exhibited the strongest and most thermo-reversible characteristics, as well as antifreezing feasibility. Another advantage of the selected fractions was the absence of skin irritation according to the in vitro skin irritation assay. [ABSTRACT FROM AUTHOR]

The current research involved creating models using Response Surface Methodology (RSM) and Support Vector Regression (SVR) to forecast the amount of extractable essential oil that can be obtained from powdered cumin seeds. Influence of microwave power (140–280–420–560–700 W), amount of water (500–600–700–800–900 ml), duration of distillation (30–45–60–75–90 min) and soak time (15–30–45–60–75 min) on essential oil yield were investigated. Microwave Assisted Extraction (MAE) allowed higher recoveries compared to conventional Soxhlet extraction, without altering the chemical components of the extract. A five-level four FCC experimental design was developed using Minitab (15.1.20.0). A total of 31 runs were performed in microwave-assisted extraction apparatus. Experimental data obtained was then used for developing RSM and SVR models for the prediction of the yield of essential oil. The optimum conditions for maximum yield of cumin oil were given by RSM. Maximum yield of 3.4 ml (0.017 ml/g) was found at 140 W of microwave power, 500 ml of water, 90 min duration of distillation, and 15 min of soak time. In this work, epsilon SVR with RBF kernel was used. The grid search (depth-first search) methodology was applied for tuning the values of epsilon, gamma, and cost using the LIBSVM module on the MATLAB interface. The statistical parameters namely, average absolute relative error (AARE), coefficient of determination (R2), standard deviation (SD), and root mean square error (RMSE) were selected as the performance parameters. The developed SVR model was compared with the RSM model. The AARE values of 2.27% and 1.29%, R2 values of 0.86 and 0.99, SD values of 1.73 and 0.29, and RMSE values of 0.0284 and 0.0132 were obtained for RSM and SVR models respectively. It is found that SVR is more accurate and better tool for modeling of MAE process. [Display omitted] • Essential oil that can be extracting from powdered cumin seeds are elucidated. • MAE is a strong novel extraction technique for the extraction of essential oils. • RSM and SVR mathematical models for the prediction of the yield of essential oil are developed. • Effect of microwave power, amount of water, duration of distillation and soak time on the yield of essential oil are studied. • The developed SVR model was compared with RSM model. [ABSTRACT FROM AUTHOR]