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Saffron ( Crocus sativus ) floral by-products are a source of phenolic compounds that can be recovered and used in the nutraceutical, pharmaceutical, or cosmetic industries. This study aimed to evaluate the phenolic compounds' extraction using green extraction techniques (GETs) in saffron floral by-products and to explore the influence of selected extraction techniques on the phytochemical composition of the extracts. Specifically, ultrasound-assisted extraction (UAE), subcritical water extraction (SWE), and deep eutectic solvents extraction (DESE) were used. Phenolic compounds were identified with (HR) LC-ESI-QTOF MS/MS analysis, and the quantitative analysis was performed with HPLC-PDA. Concerning the extraction techniques, UAE showed the highest amount for both anthocyanins and flavonoids with 50:50% v / v ethanol/water as solvent (93.43 ± 4.67 mg/g of dry plant, dp). Among SWE, extraction with 96% ethanol and t = 125 °C gave the best quantitative results. The 16 different solvent mixtures used for the DESE showed the highest amount of flavonoids (110.95 ± 5.55-73.25 ± 3.66 mg/g dp), while anthocyanins were better extracted with choline chloride:butane-1,4-diol (16.0 ± 0.80 mg/g dp). Consequently, GETs can be employed to extract the bioactive compounds from saffron floral by-products, implementing recycling and reduction of waste and fitting into the broader circular economy discussion.

The supramolecular solvent (SUPRAS) has garnered significant attention as an innovative, efficient, and environmentally friendly solvent for the effective extraction and separation of bioactive compounds from natural resources. However, research on the use of a SUPRAS for the extraction of phenolic compounds from plants, which are highly valued in food products due to their exceptional antioxidant properties, remains scarce. The present study developed a green, ultra-sound-assisted SUPRAS method for the simultaneous determination of three phenolic acids in Prunella vulgaris using high-performance liquid chromatography (HPLC). The experimental parameters were meticulously optimized. The efficiency and antioxidant properties of the phenolic compounds obtained using different extraction methods were also compared. Under optimal conditions, the extraction efficiency of the SUPRAS, prepared with octanoic acid reverse micelles dispersed in ethanol-water, significantly exceeded that of conventional organic solvents. Moreover, the SUPRAS method demonstrated greater antioxidant capacity. Confocal laser scanning microscopy (CLSM) images revealed the spherical droplet structure of the SUPRAS, characterized by a well-defined circular fluorescence position, which coincided with the position of the phenolic acids. The phenolic acids were encapsulated within the SUPRAS droplets, indicating their efficient extraction capacity. Furthermore, molecular dynamics simulations combined with CLSM supported the proposed method's mechanism and theoretically demonstrated the superior extraction performance of the SUPRAS. In contrast to conventional methods, the higher extraction efficiency of the SUPRAS can be attributed to the larger solvent contact surface area, the formation of more types of hydrogen bonds between the extractants and the supramolecular solvents, and stronger, more stable interaction forces. The results of the theoretical studies corroborate the experimental outcomes.

This study evaluated the use of a semi-continuous high-pressure hydrothermal process for the recovery of value-added products from pitaya peel. The process was carried out at 15 MPa, a water flow rate of 2 mL/min, a solvent-to-feed ratio of 60 g water/g pitaya peel, and temperatures ranging from 40 to 210 °C. The results show that extraction temperatures (between 40 and 80 °C) promoted the recovery of betacyanin (1.52 mg/g), malic acid (25.6 mg/g), and citric acid (25.98 mg/g). The major phenolic compounds obtained were p-coumaric acid (144.63 ± 0.42 µg/g), protocatechuic acid (91.43 ± 0.32 µg/g), and piperonylic acid (74.2 ± 0.31 µg/g). The hydrolysis temperatures (between 150 and 210 °C) could produce sugars (18.09 mg/g). However, the hydrolysis process at temperatures above 180 °C generated Maillard reaction products, which increased the total phenolic compounds and antioxidant activity of the hydrolysates. Finally, the use of semi-continuous high-pressure hydrothermal process can be a sustainable and promising approach for the recovery of value-added compounds from pitaya peel, advocating a circular economy approach in the agri-food industry., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Pomegranate is one of the richest fruits species in bioactive compounds, including its non-edible parts. In this work, a simple, rapid and environmentally-friend is described. It allowed the recovery of 108 mg of bioactive per gram of enriched extract from pomegranate peel (PomPE). The quality of PomPE was assessed in terms of antiproliferative activity and its influence on the sensory attributes on muffins and cheese was evaluated. Results showed an IC50 of ∼ 50 µg/ml, which was equal to extract obtained by ethanol 70%. The incorporation of PomPE in muffins formulation improved some sensory attributes by 10%. However, overall, the supplementation of cheese led to a decrease of the sensory parameters. The results concluded that the described method could be an alternative to the conventional techniques to obtain enriched extract with high potential of valorization in food and pharmaceutical sectors., (Copyright © 2022. Published by Elsevier Ltd.)

An excellent high-efficiency natural deep eutectic solvent (NADES, ChCl-MA) was screened out and integrated with pulse-ultrasonication technique for extracting phenolic compounds from Carya cathayensis Sarg. peels (CCSPs). Single factor experiment combined with response surface methodology (RSM) using Box-Behnken design (BBD) were employed to investigate significant factors and optimize their influence on extraction of phenolic compounds. Significant synergistic effect triggered by ChCl-MA based pulse-ultrasonication over other methods used alone were proved by comparative study concerning a variety of bioactive components and antioxidant activities. The second-order kinetic model was developed and validated (R 2  > 0.99) to describe the extraction process and its mechanism; and second-order kinetic extraction rate constant (k), saturation concentration (C s ), and initial extraction rate (h) were calculated. FT-IR, DSC and SEM results further demonstrated synergistic effect and influence during extraction. Overall, this study provided a green and high-efficiency alternative for the recovery of various phenolics compounds from plant source by-products., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

For more sustainable and environmentally friendly scientific research, it is essential to apply green chemistry principles in all areas of science. A possible area in which green chemistry principles can significantly influence the productivity and the quality of the outcome is extraction of natural products. The conventional toxic solvents can be replaced by environmentally friendly solvents known as deep eutectic solvents, which fortunately, due to their unique properties, can significantly improve extraction efficiency. In this literature review, the extraction of a specific class of natural products, phenolic compounds, using different types of green deep eutectic solvents has been reviewed. Within this review, the composition of those solvents used to extract different types of phenolic compounds has been discussed. In addition, the factors affecting their extraction, extracting solvent component structure, molar ratio of extracting solvent components, extraction temperature, solid to extraction solvent ratio, and water content, have been evaluated.

A HPLC-DAD/ESI-MS method has been developed and validated for the analysis of the most representative phenolic compounds in extra-virgin olive oil (EVOO) samples using a green extraction approach based on deep eutectic solvents (DESs) at room temperature. We examined ten DESs based on choline chloride and betaine in combination with different hydrogen bond donors comprising six alcohols, two organic acids, and one urea. Five phenolic compounds, belonging to the classes of secoiridoids and phenolic alcohols, were selected for the evaluation of extraction efficiency. A betaine-based DES with glycerol (molar ratio 1:2) was found to be the most effective for extracting phenolic compounds as compared to a conventional solvent. The optimization of the extraction method involved the study of the quantity of water to be added to the DES and evaluation of the sample-to-solvent ratio optimal condition. Thirty percent of water added to DES and sample to solvent ratio 1:1 (w/v) were selected as the best conditions. The chromatographic method was validated by studying LOD, LOQ, intraday and interday retention time precision, and linearity range. Recovery values obtained spiking seed oil sample aliquots with standard compounds at 5 and 100 μg/g concentration were in the range between 75.2% and 98.7%., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The objective of this study was to evaluate the potential of green solvents for extractions of bioactive compounds (BACs) and essential oils from wild thyme ( Thymus serpyllum L.) using theoretical and experimental procedures. Theoretical prediction was assessed by Hansen solubility parameters (HSPs) and conductor-like screening model for realistic solvents (COSMO-RS), to predict the most suitable solvents for extraction of BACs. An experimental procedure was performed by nonthermal technology high voltage electrical discharge (HVED) and it was compared with modified conventional extraction (CE). Obtained extracts were analyzed for chemical and physical changes during the treatment. Theoretical results for solution of BACs in ethanol and water, as green solvents, were confirmed by experimental results, while more accurate data was given by COSMO-RS assessment than HSPs. Results confirmed high potential of HVED for extraction of BACs and volatile compounds from wild thyme, in average, 2.03 times higher yield of extraction in terms of total phenolic content was found compared to CE. The main phenolic compound found in wild thyme extracts was rosmarinic acid, while the predominant volatile compound was carvacrol. Obtained extracts are considered safe and high-quality source reach in BACs that could be further used in functional food production.

This paper proposes a new sustainable and simple strategy for the micro-scale extraction of phenolic compounds from grapevine leaves with analytical purpose. The method is based on a microwave-assisted solid-liquid extraction approach (MA-SLE), using an aqueous solution of an ionic liquid (IL)-based surfactant as extraction phase. The method does not require organic solvents, nor any clean-up step, apart from filtration prior to the injection in the analytical system. Two IL-based surfactants were evaluated, and the method was optimized by using experimental designs, resulting in the use of small amounts of sample (100 mg) and extraction phase (2.25 mL), low concentrations of the selected 1-hexadecyl-3-butyl imidazolium bromide IL (0.1 mM), and 30 min of extraction time. The proposed methodology was applied for the determination of the polyphenolic pattern of six different varieties of Vitis vinifera leaves from the Canary Islands, using high-performance liquid chromatography and photodiode array detection for the quantification of the compounds. The proposed MA-SLE approach was greener, simpler, and more effective than other methods, while the results from the analysis of the leaves samples demonstrate that these by-products can be exploited as a source of natural compounds for many applications.

A microwave-assisted extraction (MAE) technology optimized by response surface methodology (RSM) was established to extract phenolic compounds from the fruit of Melastoma sanguineum . The effects of solvent composition, ratio of solvent to material, temperature, time and microwave power on phenol yield were evaluated in single-factor tests. The three parameters exerting main impacts on phenol yield were further optimized by RSM. Under optimal extraction conditions (31.33% ethanol, solvent/material ratio of 32.21 mL/g, 52.24 °C, 45 min and 500 W), the total phenolic content was 39.02 ± 0.73 mg gallic acid equivalent (GAE)/g dry weight (DW). This MAE method performed better in comparison with two conventional methods, those being maceration (25.79 ± 1.03 mg GAE/g DW) and Soxhlet extraction (18.40 ± 1.34 mg GAE/g DW), using lower process temperature, shorter irradiation time, and lower organic solvent consumption. In addition, five flavonoids (epicatechin gallate, epicatechin, rutin, pigallocatechin and quercetin) and two phenolic acids (protocatechuic acid and chlorogenic acid) in the extract were identified and quantified using UPLC-MS/MS., Competing Interests: The authors declare no conflict of interest.

The search for compounds with functional properties from natural sources has grown in recent years as people have developed healthier habits. Therefore, the aim of this study was to evaluate the extraction of bioactive compounds from various parts of unripe genipap fruit (Genipa americana L.) by using pressurized ethanol to verify which part of the fruit provides the greatest recovery of the iridoids genipin and geniposide. Two process variables were studied: temperature (50 and 80°C) and pressure (2, 12 and 20 bar). The whole fruit and the peel, mesocarp, endocarp, endocarp+seeds and seeds of the fruit were studied. The endocarp presented with the highest recovery of genipin (48.6±0.6mg/g raw material) and the extraction from the mesocarp allowed a greater recovery of geniposide (59±1mg/g raw material). The highest values of total phenolic content were obtained with mesocarp extracts. The endocarp and mesocarp extracts presented the highest antioxidant activity as measured by FRAP and DPPH. These results are promising and support the use of unripe genipap fruit as a source of iridoids and natural antioxidants., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Conventional extraction techniques for plant phenolics are usually associated with high organic solvent consumption and long extraction times. In order to establish an environmentally friendly extraction method for grape skin phenolics, deep eutectic solvents (DES) as a green alternative to conventional solvents coupled with highly efficient microwave-assisted and ultrasound-assisted extraction methods (MAE and UAE, respectively) have been considered. Initially, screening of five different DES for proposed extraction was performed and choline chloride-based DES containing oxalic acid as a hydrogen bond donor with 25% of water was selected as the most promising one, resulting in more effective extraction of grape skin phenolic compounds compared to conventional solvents. Additionally, in our study, UAE proved to be the best extraction method with extraction efficiency superior to both MAE and conventional extraction method. The knowledge acquired in this study will contribute to further DES implementation in extraction of biologically active compounds from various plant sources., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Every year, a great production of food waste is generated. These wastes have a negative effect on economic and environmental aspects even though they include a considerable quantity of phenolic compounds. Thus, in recent years, there has been much research about the recovery of phenolic compounds from food waste. Emerging technologies such as ultrasound, microwave, high hydrostatic pressure, supercritical fluid, pressurized liquid, and pulsed electric field have been accepted as alternative extraction techniques to conventional extraction techniques because of increasing extraction yield and reducing hazardous chemicals, time, and energy. This comprehensive review aims to analyze the ongoing research on applying emerging techniques in the valorization of food waste based on recent research. Also, this gives general extraction mechanisms of these techniques and compares them with each other. The findings discussed through this comprehensive review may be a valuable tool for industry to integrate economical and efficient extraction methods, converting food waste to a high-added value functional product. [ABSTRACT FROM AUTHOR]

The peel represents a significant portion of the araticum fruit (about 40%), which becomes waste after its consumption or processing. Previous studies have shown that the araticum peel is rich in phenolic compounds; however, little is known about the ideal conditions for recovering these compounds. Therefore, response surface methodology, using a central composite rotatable design, was employed to optimize the extraction process to maximize the total phenolic compounds (TPCs) and enhance the Trolox equivalent antioxidant capacity (TEAC) from araticum peel. The variables optimized were ethanol concentration (EC; 20–80%, v/v), extraction time (ET; 5–45 min), and solid–solvent ratio (SSR; 10–100 mg/mL). Additionally, condensed tannins, antioxidant capacity against synthetic free radicals (TEAC and FRAP) and reactive oxygen species (ROS), and the phenolic compounds profile, were evaluated. Optimum extraction conditions were 50% (v/v) ethanol concentration, 5 min of extraction time, and 10 mg/mL solid–solvent ratio. Under these conditions, experimental TPCs and TEAC values were 70.16 mg GAE/g dw and 667.22 µmol TE/g dw, respectively, comparable with predicted models (68.47 mg GAE/g dw for TPCs and 677.04 µmol TE/g dw for TEAC). A high condensed tannins content (76.49 mg CE/g dw) was also observed and 12 phenolic compounds were identified, predominantly flavonoids (97.77%), including procyanidin B2, epicatechin, and catechin as the major compounds. Moreover, a potent antioxidant activity was observed against synthetic free radicals and ROS, especially in scavenging peroxyl and hydroxyl radicals. From this study, we obtained the ideal conditions for recovering phenolic compounds from araticum peel using a simple, fast, sustainable, and effective method, offering a promising opportunity for the management of this plant byproduct. [ABSTRACT FROM AUTHOR]

In the study, natural deep eutectic solvents (NADESs) were used as alternatives to traditional chemical solvents for the extraction of polyphenols from Elaeagnus angustifolia L. Nine NADESs were tested for the first time and compared with ethanol and water (traditional solvents) regarding the extraction of phenolic compounds from E. angustifolia L. These solvents were particularly effective at extracting polyphenols, whose low water solubility usually requires high amounts of organic solvents. The solvent based on choline chloride and malonic acid provided optimal results and was selected for further optimization. The effects of material-to-liquid ratio, ultrasound time, and ultrasound temperature on the extraction efficiency were studied through single-factor experiments. These parameters were optimized by Box–Behnken design using response surface methodology. The optimal conditions identified were 49.86 g/mL of material-to-liquid ratio, 31.10 min of ultrasound time, and 62.35 °C of ultrasound temperature, resulting in a high yield of 140.30 ± 0.19 mg/g. The results indicated that the NADES extraction technique provided a higher yield than the conventional extraction process. The antioxidant activity of the extract of polyphenols from E. angustifolia L. was determined, and UPLC–IMS–QTOF–MS was used to analyze the phenolic compounds in it. The results revealed that the scavenging ability of 1,1-diphenyl-2-picryl-hydrazil and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) extracted by NADES was higher than that of polyphenols extracted by water and ethanol. Furthermore, a total of 24 phenolic compounds were identified in the extract. To the best of our knowledge, this is the first study in which a green and efficient NADES extraction method has been used to extract bioactive polyphenols from E. angustifolia L., which could provide potential value in pharmaceuticals, cosmetics, and food additives. [ABSTRACT FROM AUTHOR]

Cocoa bean shell (CBS), a by-product from the chocolate industry, is an interesting source of bioactive compounds. In this work, the effects of time and pH on the hydrothermal hydrolysis of CBS were evaluated with the aim of maximizing the extraction of antioxidant and functional compounds from this biomass. In general, all treatments tested led to improvements in the extraction of bioactive compounds compared to untreated samples. The maximum values for antioxidant activity (187 µmol TE/g CBS dw) and phenolic compounds (14.5 mg GAE/g CBS dw) were obtained when CBS was treated at pH 4 for 10 min. In addition, maximum amounts of flavonoids (10.1 mg CE/g CBS dw), tannins (6.5 mg CE/g CBS dw) and methylxanthines (9 mg/g CBS dw) were obtained under mild pH conditions (4–5). It is noteworthy that these values are higher than those reported in the literature for other vegetable substrates, highlighting the potential of CBS to be valorized as a source of different value-adding products. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the present study, natural deep eutectic solvents (NADES) as a novel green tool were used for the recovery of bioactive compounds with respect to the valorization of artichoke outer petals. NADES coupled with ultrasound-assisted extraction was applied by varying the type of hydrogen bond acceptors (choline chloride or betain) and hydrogen bond donors (sucrose, lactic acid, citric acid, oxalic acid and glycerol) in the NADES mixtures. Thereafter, extraction efficacy was assessed in terms of total phenolic content, antioxidant capacity and individual phenolic composition and their levels by comparing the results obtained by NADES with those for a reference methanolic extract. RESULTS: Based on the results of the present study, the use of choline chloride and lactic acid mixtures was superior for obtaining extracts with high levels of phenolic compounds (12.96 g GAE kg-1 DW) and high antioxidant potential (60.68 g TE kg-1 DW). In addition, gallic acid, syringic acid, chlorogenic acid, ferulic acid, sinapic acid, luteolin, apigenin, rutin and quercetin were detected in all extracts by chromatographic evaluation. As major phenolic compounds, chlorogenic acid and ferulic acid were found to be maximum in lactic acid-based NADES mixtures. CONCLUSION: The present study reveals the potential treatment of various plants, wastes or by-products with NADES combined with an ultrasonication method for the extraction of bioactive compounds with enhanced recovery and selectivity, with the aim of incorporating them into various food and pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

The mushroom industry should implement green extraction technologies; however, there is not enough information on the differences between these techniques expressed as the chemical composition of the resulting extract. In this study, selected types of green extraction techniques (GETs) were used on Chaga (Inonotus obliquus) (Fr.) Pilát from Serbia (IS) and Mongolia (IM) to examine the differences that would enable the composition-based technology choices in the mushroom supplement industry. Subcritical water extraction (SWE), microwave-assisted (MW) extraction, and ultrasonic-assisted extraction (VAE) were used to prepare the extracts. SWE was performed at two different temperatures (120 and 200 °C), while 96% ethanol, 50% ethanol, and water were used for MW and VAE. The yield, the content of total phenols, total proteins, and carbohydrates, qualitative and quantitative analysis of phenolic compounds, carbohydrates, including α- and β- and total glucans, and fatty acids, were determined in the obtained extracts. SWE resulted in a significantly higher yield, total polysaccharide, and glucan content than any other technique. Glucose was the most dominant monosaccharide in the SWE samples, especially those extracted at 200 °C. The MW 50% EtOH extracts showed the highest yield of total phenols. Among the tested phenolic compounds, chlorogenic acid was the most dominant. SWE can be recommended as the most efficient method for extracting commercially important compounds, especially glucans and phenols. [ABSTRACT FROM AUTHOR]

Aeginetia indica L., a parasitic root in the Orobanchaceae family, is used as a food colorant in traditional Thai desserts. However, scant information is available on its food applications as well as medicinal properties, while overharvesting by the local people has severely depleted wild plant populations. This research, thus, aimed to extract optimized total phenolic content (TPC) in varying extraction conditions using response surface methodology (RSM) and the Box–Behnken design (BBD). Results indicated that an extraction temperature of 90 °C, 80% (v/v) aqueous ethanol, and 0.5% (w/v) solid-to-liquid ratio yielded the highest TPC at 129.39 mg gallic acid equivalent (GAE)/g dry weight (DW). Liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) identified the predominant phenolics as apigenin (109.06 mg/100 g extract) and luteolin (35.32 mg/100 g extract) with trace amounts of naringenin and rutin. Under the optimal extraction condition, the plant extract exhibited antioxidant activities of 5620.58 and 641.52 µmol Trolox equivalent (TE)/g DW determined by oxygen radical absorbance capacity (ORAC) and ferric ion reducing antioxidant power (FRAP) assay, while the scavenging capacity of total radicals at 50% (SC50) was determined to be 135.50 µg/mL using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The plant extract also exhibited inhibitory activities against the key enzymes relevant to type II diabetes, obesity, and Alzheimer's disease, suggesting the potential for medicinal applications. [ABSTRACT FROM AUTHOR]

Extracting valuable compounds from waste plant tissues is a challenging process. To better understand this process, kinetic modeling was used to study the extraction of phenolic compounds from the waste tissues of industrial strawberry (RF) and apple (GS) processing using green solvents. The experimental design variables included type of solvent (W: water, EtOH: ethanol 80%), solid–liquid ratio (1:20, 1:30, 1:40), and temperature (20, 70°C). The model of Peleg (MI) and an empirical model (MII) were applied to determine the kinetic constants for total phenolic compounds (TPC) and antioxidant capacity (AC). The phenolic compound profile was determined at each experimental assay. The extraction variables affected (p < 0.001) TPC and AC of RF and GS extracts. Using EtOH increased TPC extraction yields from both tissues (up to 62% for RF). The highest AC was determined in EtOH extracts at 20°C (119 and 25 μmol TE/g for RF and GS, respectively). Temperature, extraction ratio, and solvent type significantly affected the kinetic constants of both models. The study identified nine phenolic compounds from both waste tissues, with Agrimoniin being the main compound in RF (0.49 g/kg) and quercetin pentoxide being the main compound in GS (0.23 g/kg). There was no significant increase in TPC and AC of the extracts after 90 min at 20°C and 60 min at 70°C. The kinetic modeling of phenolic compound extraction from strawberry and apple agro‐industrial by‐products using green solvents enabled the determination of the best extraction conditions, promoting the use of these waste tissues by obtaining bioactive compounds with antioxidant potential. Practical Applications: This study provides valuable insight into the effective use of green solvents in extracting bioactive compounds, thereby promoting sustainable practices and reducing waste in the industrial processing of strawberries and apples. The kinetic modeling approach for recovering phenolic compounds from strawberry and apple agro‐industrial by‐products improves our comprehension of the influence of the extraction process variables on the phenolic compound profile and antioxidant capacity of these tissues. These findings highlight the potential of these waste tissues as an alternative source of bioactive compounds. By standardizing the extraction process and optimizing the utilization of agro‐industrial by‐products, the food industry can effectively reduce the environmental impact of these waste tissues and promote sustainable operations. Additionally, using green solvents aligns with the increasing demand for environmentally friendly practices, making it easier to turn strawberry and apple agro‐industrial processes into circular processes by eco‐friendly valorization of these biowastes. [ABSTRACT FROM AUTHOR]

Phenolic compounds are known to have a significant effect on human defense system due to their anti-inflammatory efficacy. This can slow down the aging process and strengthen the human immune system. With the growing interest in green chemistry concept, extraction of phenolic compounds from plants has been geared towards a sustainable path with the use of green and environmentally friendly solvents such as natural deep eutectic solvents (NADES). This review discusses both the conventional extraction and the advanced extraction methods of phenolic compounds using NADES with focus on microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) techniques ensued by a rationale comparison between them. Employing choline chloride-based natural deep eutectic solvents (NADES) is highlighted as one of the promising strategies in green solvent extraction of phenolic compounds in terms of their biodegradability and extraction mechanism. The review also discusses assistive extraction technologies using NADES for a better understanding of their relationship with extraction efficiency. In addition, the review includes an overview of the challenges of recovering phenolic compounds from NADES after extraction, the potential harmful effects of NADES as well as their future perspective. [ABSTRACT FROM AUTHOR]

Background: Bioactive compounds from vegetables have played a substantial role as therapeutic agents in drug discovery since it contains nutraceutical and nutraceutical properties. Cucurbitaceae family encompasses several edible plants that contain valuable natural compounds. Objectives: To evaluate the physicochemical and mineral composition on Momordica charantia fruit residues. Materials and Methods: The physiochemical composition and mineral composition were characterized by FTIR and optical emission spectrophotometer, respectively. The phenolics, flavonoids and total antioxidant activity were employed by spectrophotometrically. The green ultrasound assisted extraction was used for aqueous and 12% ethanolic extraction for evaluation of phenolic compounds by UPLC/MS. Results: The results revealed the minerals such as K, P, Ca, Na, Mg, Fe, Zn, Sr, Cu and Mn found in bitter melon. High contents of total phenolics content (683.820 to 1753.345 galic acid: quercetin (2:1)/100 g of sample) and total flavonoids (106.206 to 311.423 mg of quercetin/100 g of sample) were observed in peel aqueous extract. The aqueous extract of peel exhibited maximum inhibitory potential against DPPH radical (93% of inhibition) than ethanolic extract. This aqueous extract of peel also contains naringenin, catechin, epicatechin, p-coumaric, ferulic and chlorogenic acids which were reveled from UPLC/MS analysis. Conclusion: This study suggests that M. charantia residues are good sources of functional proteins, lipids, fibers and minerals, resulting in greater nutritional value. In addition, M. charantia is of great interest in its promising benefits for human health, due to its antioxidant capacity and bioactive compounds. [ABSTRACT FROM AUTHOR]

We aimed to study the obtention of valuable phenolic compounds from tissue by-products of agro-industrial processing of apple (GS) and strawberry (RF) using green solvents and Soxhlet extraction methodology. The effects of solvent type [water (W); 80% ethanol, (EtOH)] and extraction ratio (1:10, 1:20, 1:30, and 1:40 p/v) were determined on total phenolic content (TPC), antioxidant capacity (DPPH), and the profile of phenolic compounds of the GS and RF extracts. The solvent type and the extraction ratio significantly affected TPC and DPPH of GS and RF extracts. Extraction with EtOH and 1:40 ratio produced the highest yields, obtaining an RF extract with 15.8 g GAE/Kg (TPC) and 19 mmol TE/Kg (DPPH). The tetra-galloyl glucose isomer and agrimoniin (0.8-0.4 g/Kg) were the main RF phenolic compounds of the eight identified. GS extract, obtained with EtOH and 1:40 ratio, had 11.9 g GAE/Kg (TPC) and 20.5 mmol TE/Kg (DPPH), having quercetin -3-o-glucuronide (0.43 g/Kg) the highest concentration among the eight phenolic compounds identified. The results highlight the potential of green solvents to obtain valuable compounds from low-cost raw materials, like the high-antioxidant capacity phenolic compound extracts obtained herein. [ABSTRACT FROM AUTHOR]

Current trends in the use of new pigments of natural origin have led to the investigation of novel technologies for obtaining them. The objectives of this study were to evaluate the extraction process by microwave (MAE) and ultrasound (UAE) assisted techniques and a treatment using simultaneously both techniques (hybrid way) (HM-UE) of pigments from corn with different shades of red (highly pigmented corn = RA, moderately pigmented corn = RM and poorly pigmented corn = RB), and to determine the color, content of hydrolyzable polyphenols, condensed tannins, and antioxidant potential by DPPH, ABTS and FRAP tests. Finally, the pigments obtained by HM-UE underwent thermogravimetric analysis (TGA) and were characterized by Fourier transform infrared spectrometry (FTIR) and HPLC-MS. Results indicated that hybrid-assisted extraction (HM-UE) yields higher extraction yields (p

Avocado tree pruning activities generate a substantial amount of residual biomass, which includes different parts of the plant, such as leaves, twigs, branches, and small fruits. This study aimed to investigate the impact of different green extraction methods of microwave‐assisted extraction (MAE) and ohmic heating‐assisted extraction (OHAE) for the phenolic extraction of avocado leaves based on a statistical approach, central composite design (CCD), and response surface methodology (RSM). Water was preferred using as an environmentally and health‐friendly solvent for both methods. The phenolic composition, antioxidant activity, and antidiabetic potential of the extracts were identified and comparatively assessed. The developed models exhibited a high degree of reliability with optimal conditions for OHAE and MAE, which were determined as 9.38 V/cm voltage gradient, 6 min extraction time, at 60°C, 5 min, and 1 g dried leaf/100 mL water. Epicatechin was identified as the primary phenolic compound in OHAE extracts, while chlorogenic acid was the dominant compound in MAE extracts. The extracts obtained from OHAE and MAE were tested for their ability to inhibit α‐glucosidase activity, with IC50 (mg/mL) values of 0.85 and 1.14, respectively. The DPPH radicals scavenging activity (IC50 mg/L) of OHAE and MAE were detected as 2.96 and 3.41, respectively. In conclusion, both methods yielded extracts rich in polyphenols that displayed high antioxidant activity, but OHAE was found to be superior to MAE in terms of TPC, DPPH, and antidiabetic activities. The results of this study have the potential to make significant contributions toward promoting the principles of a circular economy by facilitating the valorization of the avocado pruning waste. [ABSTRACT FROM AUTHOR]

The interest on the use of natural sources in the food industry has promoted the study of plants' phenolic compounds as potential additives. However, the literature has been focusing on essential oils, with very few studies published regarding aqueous extracts, their phenolic composition, and bioactivity. A systematic review was conducted on different databases following PRISMA guidelines to evaluate the relevance of the phenolic content of different aromatic spices (oregano, rosemary, thyme, ginger, clove, and pepper), as related to their bioactivity and potential application as food additives. Although different extraction methods have been applied in the literature, the use of green approaches using ethanol and deep eutectic solvents has increased, leading to the development of products more apt for human consumption. The studied plants present an interesting phenolic profile, ranging from phenolic acids to flavonoids, establishing a correlation between their phenolic content and bioactivity. In this sense, results have proven to be very promising, presenting those extracts as having similar if not higher bioactivity than synthetic additives already in use, with associated health concerns. Nevertheless, the study of spices' phenolic extracts is somehow limited to in vitro studies. Therefore, research in food matrices is needed for more understanding of factors interfering with their preservation activity. [ABSTRACT FROM AUTHOR]

Blackthorn fruits are rich source of polyphenols that exert numerous biological activities. But, diverse structure and polarity of phenolic compounds limit their extractability and bioavailability. Therefore, the efficiency of a green co-solvent p-cyclodextrin was examined in boosting the blackthorn polyphenols extraction. Compared to water, as the greenest solvent, 13-cyclodextrin was the most efficient in the extraction of flavonoid glycosides quercetin 3-0-glucoside and cyanidin 3-0-glucoside with the extraction rate increase of over 50 % and 40 %, respectively. The second advantage of the 0-cyclodextrin use was its intrinsic capability of simultaneous encapsulation of the compounds, through inclusion complexes formation. Scanning electron microscopy, thermogravimetric analysis, and controlled release of the dominant blackthorn polyphenols were used for the encapsulation confirmation and physico-chemical characterization. Encapsulation process reached the efficiency of 76.73 %, providing amorphous particles in the micrometer scale. The effect of the encapsulates on the growth of human MCFL HT-29, and MRC-5 cells was evaluated in vitro. In silico molecular docking analysis was performed to generate data about the most probable ligand poses and binding mechanisms of 4-cyclodextrin encapsulated blackthorn polyphenols. Flavonoid glycosides were most preferably extracted and encapsulated. Rings A and C of fiavonoid core enter the hydrophobic hole of 0-cyclodextrin and hydrogen bonds are the most responsible for the complex stabilization. [ABSTRACT FROM AUTHOR]

Enzyme-assisted extraction is considered an environmentally friendly technique. Cellulase, pectinase and protease were tested for cupuassu seeds fat extraction. The best fat efficiency (81.66%) was obtained for the solute:solvent 1:5 (m:w), orbital shaker at 120 rpm, 60 °C, for 8 hours and enzyme concentrations (cellulase, pectinase and protease) of 1.0%. The fat was characterized for physicochemical properties, fatty acid profile, phenolic compounds, antioxidant activities and oxidative stability. The fat showed good thermal stability (14.26 h) and high contents of monounsaturated (42.42%) and saturated (43.47%) fatty acids with higher concentrations of oleic and stearic acids, respectively, and a high content of phenolic compounds (141.84 µg EAG·g-1) in the fat, and in the aqueous extract (926.47 µg EAG·g-1). The results indicated that the cupuassu seed fat obtained by enzymatic extraction showed superior properties to cupuassu fat obtained by cold pressing, in addition to generating an aqueous fraction which is rich in bioactive compounds that can be used as ingredients in the food and pharmaceutical sectors. [ABSTRACT FROM AUTHOR]

Phenolic compounds have recently gained interest, as they have been related to improvements in health and disease prevention, such as inflammatory intestinal pathologies and obesity. However, their bioactivity may be limited by their instability or low concentration in food matrices and along the gastrointestinal tract once consumed. This has led to the study of technological processing with the aim of optimizing phenolic compounds' biological properties. In this sense, different extraction systems have been applied to vegetable sources for the purpose of obtaining enriched phenolic extracts such as PLE, MAE, SFE, and UAE. In addition, many in vitro and in vivo studies evaluating the potential mechanisms of these compounds have also been published. This review includes a case study of the Hibiscus genera as an interesting source of phenolic compounds. The main goal of this work is to describe: (a) phenolic compound extraction by designs of experiments (DoEs) applied to conventional and advanced systems; (b) the influence of the extraction system on the phenolic composition and, consequently, on the bioactive properties of these extracts; and (c) bioaccessibility and bioactivity evaluation of Hibiscus phenolic extracts. The results have pointed out that the most used DoEs were based on response surface methodologies (RSM), mainly the Box–Behnken design (BBD) and central composite design (CCD). The chemical composition of the optimized enriched extracts showed an abundance of flavonoids, as well as anthocyanins and phenolic acids. In vitro and in vivo studies have highlighted their potent bioactivity, with particular emphasis on obesity and related disorders. This scientific evidence establishes the Hibiscus genera as an interesting source of phytochemicals with demonstrated bioactive potential for the development of functional foods. Nevertheless, future investigations are needed to evaluate the recovery of the phenolic compounds of the Hibiscus genera with remarkable bioaccessibility and bioactivity. [ABSTRACT FROM AUTHOR]

The fruits of Rosa pimpinellifolia are rich sources of (poly)phenols, however they are underutilized due to the limited information available. The influence of the pressure, temperature, and co-solvent concentration (aqueous ethanol) of the supercritical carbon dioxide extraction (SCO2-aqEtOH) on the extraction yield, total phenolic-, total anthocyanin-, catechin-, cyanidin-3-O-glucoside contents, and total antioxidant activity of black rosehip was investigated simultaneously. The maximum obtained total phenolic and total anthocyanin contents under the optimized extraction conditions (280 bar, 60 °C and 25% ethanol, v/v) were 76.58 ± 4.25 mg gallic acid equivalent and 10.89 ± 1.56 mg cyanidin-3-O-glucoside equivalent per g of the dry fruits, respectively. The optimal extract obtained by SCO2-aqEtOH was compared to two other extraction procedures: ultrasonication using ethanol as solvent (UA-EtOH) and pressurized hot water extraction (PH-H2O). The bioaccessibility and cellular metabolism of the phenolic compounds in the different black rosehip extracts were assessed using an in vitro digestion coupled with a human intestinal Caco-2 cell model. The in vitro digestive stability and cellular uptake of the phenolic compounds had no significant difference among the different extraction methods. The results of this study confirm the efficiency of SCO2-aqEtOH extraction for phenolic compounds and, in particular, for anthocyanins, and could be used to produce new functional food ingredients from black rosehip with high antioxidant power containing both hydrophilic and lipophilic compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • The pomegranate peel polyphenols in pomegranate peel were effectively and promptly extracted by DES-UA. • Glycerol/urea-UAE had the highest TPC yield compared with other solvents and methods. • The extraction conditions for extracting pomegranate peel polyphenols were optimized. • Sixty-two compounds were identified by UPLC-Q-TOF-MS/MS analysis. • This study promotes the reuse of waste resources and protects the environment. Polyphenols are extensively utilized for their antioxidant, anti-tumor, and anti-aging properties, and have demonstrated effectiveness in the treatment of heart and vascular diseases. Pomegranate, a medicinal and food homologous plant, has been extensively used in both conventional and modern medical research. DESs are new solvents with low toxicity, safety and high extraction capacity and are increasingly widely used in various fields. In this study, DES combined with ultrasound was applied to extract polyphenols from pomegranate peel, and the selected glycerol-urea system was optimized. According to the experiment, the conditions of extracting polyphenols from pomegranate peel were glycerol/urea (1:2, mol/mol), water content 30 %, extraction time 20 min, extraction temperature 30 ℃, liquid/solid ratio 70 mL/g, and ultrasonic power 300 W. The maximum total phenolic content was 81.983 GAE mg/g DW, which was 1.14–2.21 times higher than that of the other extraction solvents and methods, and DES revealed a remarkable increase of extraction efficiency. UPLC-Q-TOF-MS/MS analysis showed that polyphenols were the main components in pomegranate peel, and 47 of the 62 substances identified were phenolic compounds. This study presents a viable approach to facilitate the green, efficient and convenient extraction and reutilization of polyphenols from pomegranate peel waste resources, thereby advancing ecologically and environmentally sustainable development. [ABSTRACT FROM AUTHOR]

Cancer is a worldwide epidemic and a leading cause of death. There is a need to find natural solutions for therapy to prevent that outcome. Olive pomace is a known source of bioactive compounds. This work aimed to obtain an olive pomace extract, using an innovative green method, and to assess its chemical composition and the effect of its application in different cancer cell lines. The extract was composed of sugars (28%), minerals (11%), lipids (8%), mostly oleic acid (72%), protein (1%), phenolics (3 g gallic acid equivalents/100 g), hydroxytyrosol (215 mg/100 g), flavonoids (2 g catechin equivalents/100 g), and α-tocopherol (2 mg/100 g). Moreover, 68 phenolics were tentatively identified by UHPLC-ESI-QTOF-MS. The extract significantly reduced the proliferation of the studied cancer cell lines (breast: MCF-7; pancreatic: AsPC-1; and colorectal: HT-29 and Caco-2). It was able to reduce angiogenesis in AsPC-1 cells, presented a cytotoxic effect and increased malondialdehyde levels in HT-29 cells, and decreased growth of Caco-2 cells. These results suggest that this extract can be a source of several compounds which can be used in the formulation of dietary supplements or as a structural basis for antitumoral drugs, but their mechanistic actions still need to be assessed. [ABSTRACT FROM AUTHOR]

In this work, pressurized hot water extraction (PHWE) of hydrophilic polyphenols from black rosehip fruit was maximized using response surface methodology for simultaneous optimization in terms of extraction yield, total antioxidant capacity, total (poly)phenols, catechin, total monomeric anthocyanins, and cyanidin-3-O-glucoside. Extraction parameters, including temperature (X1: 40–80 °C) and the solvent-to-solid ratio (X2: 10–40 mL/g), were investigated as independent variables. Experimentally obtained values were fitted to a second-order polynomial model, and optimal conditions were determined using multiple regression analysis and analysis of variance. The black rosehip extract (BRE) obtained at optimized PHWE conditions was further encapsulated in biopolymer-coated liposomes and spray dried to enhance its processing and digestive stability. After reconstitution, the fabricated particles had an average size of 247–380 nm and a zeta-potential of 15–45 mV. Moreover, encapsulation provided remarkable protection of the phenolics under in vitro gastrointestinal digestion conditions, resulting in up to a 5.6-fold more phenolics in the bioaccessible fraction, which also had 2.9–8.6-fold higher antioxidant activity compared to the nonencapsulated BRE. In conclusion, PHWE in combination with a biopolymer coating is a potent method for the production of stable and safe edible natural extracts for the delivery of (poly)phenolic compounds in food and dietary supplements. [ABSTRACT FROM AUTHOR]

Avocado peels are the main agro-industrial residue generated during the avocado processing, being a rich source of bioactive compounds like phenolic compounds. The growing demand for more sustainable processes requires the development of new and effective methods for extracting bioactive compounds from industrial waste. Deep eutectic solvents (DESs) are a new sustainable alternative to toxic organic solvents due to their non-toxicity and biocompatibility. In this study, five selected DESs were applied for the extraction of bioactive phenolic compounds from avocado peels. The extraction efficiency was evaluated by measuring the total phenolics and flavonoids content. The best extraction results were obtained with choline chloride-acetic acid and -lactic acid (92.03 ± 2.11 mg GAE/g DAP in TPC and 186.01 ± 3.27 mg RE/g DAP); however, all tested DESs show better extraction efficiency than ethanol. All the obtained NADES extracts have high antioxidant activity (FRAP: 72.5–121.1 mg TE/g; TAC: 90.0–126.1 mg AAE/g). The synthesized DESs and avocado peels DES extracts had activity against all tested bacteria (Staphylococcus aureus, Streptococcus dysgalactiae, Escherichia coli and Pseudomonas putida), and the extracts prepared with choline chloride-acetic acid and -lactic acid have the highest antibacterial activity against all microorganisms. These results, coupled with the non-toxic, biodegradable, low-cost, and environmentally friendly characteristics of DESs, provide strong evidence that DESs represent an effective alternative to organic solvents for the recovery of phenolic bioactive compounds from agro-industrial wastes. [ABSTRACT FROM AUTHOR]

Araçaúna (Psidium myrtoides) is a native fruit from the Brazilian Atlantic Forest. It was studied for the proximate composition of its flour and sequential extraction using supercritical fluid extraction (SFE) in the first stage with CO 2 and pressurized liquid extraction (PLE) with ethanol and water in the second and third stages, respectively, at 50°C and 60°C. The proximate analysis revealed essential information about the flour regarding the content of protein, carbohydrates, lipid, ash and moisture. The sequential extraction at 60°C resulted in high yields (42.22 %). The first stage using SFE captured the volatile fraction, notably 1,4-diethylbenzene, which corresponds to 53.70 % of the total volatile compounds identified in the araçaúna. Comparing the second and third stages, the third stage with water at 50°C produced the highest levels of phenolic compounds (33.06±2.26 mg GAE/g extract), total monomeric anthocyanins (3.91±2.10 mg C3G/g extract), antioxidant activity by ORAC (415.13±13.66 µmol TE/g extract) and FRAP (747.16±18.49 µmol TE/g extract), and cyanidin-3-glucoside as the predominant compound (4.83 % w/w). [Display omitted] • Sequential extraction with scCO2, ethanol, and water yielded distinct extracts. • Higher temperatures result in higher extraction yields (41.97 %). • 1,4-diethylbenzene was captured in higher percentage in the first stage with scCO2. • Higher concentration of bioactive compounds in the third stage with water. • Identification of cyanidin-3-glucoside as the main anthocyanin compound. [ABSTRACT FROM AUTHOR]

Summary: The exploitation of phenolic compounds in different fields has motivated researchers to explore eco‐friendly and efficient extraction techniques. This study aimed to comparatively reveal that green extraction techniques (microwave‐ and ultrasound‐assisted) are alternative to conventional extraction (maceration and magnetic stirring) with positive impact on the phenolic content, antioxidant activity, and bioactive profile of bee pollen extracts. The highest total phenolic and flavonoid content was reached using the microwave‐assisted technique (MAE) with equivalent values of 28 and 8 mg g−1, with magnetic stirring and maceration showing a lower value. The composition profile of the extracts revealed the presence of twenty‐six bioactive compounds, including thirteen phenolics and thirteen phenylamides. Although the extraction technique had little impact on the chemical diversity, the amount of bioactive compounds raised significantly with the use of the green extraction techniques, with gains between 40% and 60% for phenolics and up to 200% for phenylamides. The radical scavenging activity and the reducing power of the extracts confirmed that bee pollens are potent antioxidant source, with the most bioactive extracts corresponding to green extraction techniques. Consequently, all findings recommend the use of MAE as the technique most effective for the extraction of bioactive compounds from naturally encapsulated structures such as bee pollen. [ABSTRACT FROM AUTHOR]

Garcinia mangostana (GM) pericarp extract recognizes for relieving skin disorders. It becomes a household fruit juice due to its high concentration of antioxidant compounds, including phenolic and α-mangostin. The purpose of this study was to optimize the conditions of Ultrasonic-Microwave Assisted Extraction (UMAE) of GM pericarp. GM pericarp was extracted by UMAE and conventional decoction extraction. UMAE was created in nine different individuals and combined ultrasonic and microwave power. The amount of phenolic compound, "caffeic acid, ferulic acid", α-mangostin, and total phenolic content (TPC) were compared. The optimized parameters were particle size of grounded raw material, microwave power, and ultrasonic power during water extraction. The optimized UMAE conditions combined 200 W microwave power and 200 W ultrasonic power to extract raw material grounded to 22.6 μm diameter particles (p≤0.05). The synergistic effect of ultrasonic and microwave-assisted extraction significantly (p≤0.05) impacted on the TPC, the yield of caffeic acid, ferulic acid, and α-mangostin. Overall, the synergistic effect of ultrasonic and microwave extraction resulted in a significantly higher amount of bioactive compounds when compared to conventional decoction extraction (p≤0.001). These results demonstrated the advantages of UMAE for preparing GM pericarp extract for the food, cosmetic and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Carob syrup is one of the most important carob products, which can have applications in pastry and confectionery, as a fruit preservative, but also in the pharmaceutical field because of the antimicrobial activity due to its polyphenol content. Carob syrup is traditionally made through a very time-consuming process, involving solid–liquid extraction in boiling water and concentration at a high temperature (>100 °C), which potentially causes the degradation of the active compounds (i.e., procyanidins or flavonol glycosides). Therefore, in this work, an alternative and less drastic method based on ultrasound technology was proposed to produce carob syrup. Processing conditions (i.e., time, temperature, and liquid–solid ratio) influencing the extraction of total soluble solids (TSS) and total phenolic compounds (TPC) were optimized using a central composite design coupled to response surface methodology. Reliable mathematical models allowed us to predict the highest TSS (24 ± 2 °Brix) and TPC (1.7 ± 0.5 mg/mL) values that could be obtained at 15 min, 35 °C, and 2 mL/g. Finally, a different HPLC-DAD phenolic pattern was determined between syrups produced by traditional and ultrasound methods; epicatechin, 4-hydroxycoumaric acid, and ferulic acid were more concentrated in the former, while procyanidin B2, myricitrin, and quercitrin were prevalent in the latter one. [ABSTRACT FROM AUTHOR]

Summary: Phenolic compounds (PCs) have been finding increasing applications in functional foods, cosmetic, pharmaceutical and nutraceuticals due to their nutritional and antioxidant properties. Considering the drawbacks of conventional extraction methods, there is an ongoing challenge for researchers to develop green extractions (GE) of PCs in a sustainable and eco‐friendly way. A bibliometric study is a valuable tool to provide quantitative information for evaluating the scientific research activity based on the available published scientific literature. This bibliometric study aims for the first time to unravel the scientific exploration towards the GE of phenolics from plant by‐products, that is, leaves by focussing on scientific publications collected through the Web of Science database. Consequently, insights into the evaluation of publication trends, authors, countries, organisations, keywords, journals, publishers and citations in support of GE were established. The critical evaluation of the results showed an increase in research, during the last decade, on GE of PCs from leaves. The study also revealed Europe as the leader in terms of publications, citations, countries, organisations, as well as authors contributing to this research topic. Following the analysis, directions for future research have also been suggested. [ABSTRACT FROM AUTHOR]

In this study the combined effect of mechanical comminution and pulsed electric fields (PEF) treatments on both cell disintegration and extractability of phenolic compounds during aqueous extraction from artichoke external bracts, was investigated. Different-sized bract discs were treated with varying PEF conditions, namely 0.5–5 kV/cm of electric field strength (E), and 1–20 kJ/kg of total specific energy input (W T). The cell disintegration index (Z p) of bract tissues, as well as the total phenolic content (TPC) and antioxidant activity (FRAP) of the extracts, were assessed. The results showed that increasing the comminution process intensity led to greater cell disintegration, resulting in a peak extraction yield of phenolic compounds (17.61 ± 1.24 mg GAE /100 g FW) achieved with the smallest sample size. Moreover, the application of PEF treatment further increased the Z p value of the bract tissues in a size-dependent manner. The greater the sample size, the stronger the PEF efficiency. Coherently, under optimized PEF conditions (E = 3 kV/cm, W T = 5 kJ/kg), the extracts exhibited higher TPC (+112–361%) and FRAP values (+83–836 %) as compared to the control samples after 120 min of diffusion. The extraction rate of phenolic compounds increased when the comminution degree was increased for both untreated and PEF-treated samples, and this was successfully predicted using Peleg's model. These findings suggest that PEF can be a viable alternative to energy-intensive comminution pretreatment, thus enhancing the extraction of phenolic compounds without requiring finely ground raw material handling. • Mechanical comminution induces cell disruption at the cutting area. • PEF efficiency depends on particle size. • PEF reduces the need for intensive mechanical comminution of raw material. • PEF pre-treatment intensify the extractability of phenolics from artichoke bracts. • Phenolic compounds extraction kinetic is well fitted by Peleg's model. [ABSTRACT FROM AUTHOR]

The phenolic compounds of blackberries extracted with organic solvents cause environmental damage. Therefore, the objective of the present study was to verify if microwave hydrodiffusion and gravity obtain a blackberry extract with a high concentration of phenolic compounds and antioxidant capacity without the addition of any solvent. The results showed that it was possible to reach the objective with 500 W and 10 min of extraction by employing a method that meets green chemistry principles. The extract has a lower cost than the exhaustive method, is microbiologically safe, and is mainly composed of anthocyanins (85%). The presence of 5 anthocyanins and 17 non-anthocyanin phenolic compounds were identified, including hydroxyresveratrol, which was first extracted in blackberries by microwave hydrodiffusion and gravity. The phenolic compound content and antioxidant capacity were lower in the last fractions, which reduced the extraction time to 8 min. The coproduct showed phenolic, antioxidant capacity, and microbiological quality. This study presented a fast, efficient, economical, sustainable, and solvent-free method to extract phenolic compounds from blackberries. [ABSTRACT FROM AUTHOR]

Rapid technological progress focuses on lowering costs, labor and time. Thus, in order to minimize the expenses of bioactive compound production, great effort is undertaken to optimize the extraction of these compounds. Green extraction is popular and relatively inexpensive. However, the same extraction method does not always work for all types of matrixes due to the biological diversity of the tissue. Therefore, the purpose of this study was to identify the optimal green extraction method of açai berries (ultrasound or microwaves) able to isolate extracts containing the highest possible number of phenolic compounds with the highest antioxidant activity. The results show that the highest content of total phenolic compounds in the extracts was obtained after the application of a temperature of 45 °C, using ultrasound for 25 min and 45 min, microwaves for 3.16 min and a water bath for 25 min. Ultrasound turned out to be the most effective method of flavonoid extraction. In turn, the highest anthocyanin content was obtained for microwave extraction. Additionally, the application of microwaves for 4.33 min (45 °C) guaranteed the highest ferric-reducing antioxidant activity (FRAP) among the extracts. The results show that the use of microwaves shortens the açai extraction time and ensures both a high content of total phenolic compounds and strong antioxidant activity in the extract. [ABSTRACT FROM AUTHOR]

Grape pomace is a by-product that contains high amounts of phytochemicals such as phenolic acids, flavonoids, and anthocyanins. For the efficient extraction of these compounds, extraction optimization was done in the present study. Glycerol concentration, a cheap, non-toxic and abundant green solvent, and liquid–solid ratio were evaluated as the independent factor of the optimization and total phenolic content, total flavonoid content, free radical scavenging activity, total monomeric anthocyanin content, total proanthocyanidin content and ascorbic acid content was analyzed as responses. The result showed that glycerol concentration significantly affected all responses and increasing the concentration resulted in higher extraction of the phytochemicals. Additionally, liquid–solid ratio affected total phenolic content, total flavonoid content, total proanthocyanidin content and ascorbic acid content of the extracts. Glycerol concentration of 50% (w/v) and liquid–solid ratio of 22.4 was determined to be optimum condition to maximize all responses. The optimum conditions were experimentally validated. Overall, the study showed that homogenizer assisted extraction using glycerol as a green solvent is a good method for extraction of phytochemicals from food processing by-products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficacy of the phenolic extraction from agro-byproduct can be augmented by merging two or more nonthermal techniques. • Studies must be done on Naviglio extractor® , Cold plasma, and high-hydrostatic pressure extraction of polyphenols. • The safety of extraction technologies on the polyphenolic extract from agro-byproduct is needed in vivo and in vitro studies. • Investigation is required to explore sequencing process and its potential impact on extraction of phenolic from byproduct. • Operation costs and efficiency are constraints on agro-byproduct phenolics that must be solved by biotechnological systems. The agro-food industries generate significant waste with adverse effects. However, these byproducts are rich in polyphenols with diverse bioactivities. Innovative non-thermal extraction (NTE) technologies (Naviglio extractor®, cold plasma (CP), high hydrostatic pressure (HHP), pulse-electric field (PEF), ultrasound-assisted extraction (UAE), etc.) and their combinative effect (integrated UAE + HPPE, integrated PEF + enzyme-assisted extraction, etc.) could improve polyphenolic extraction. Hence, this article comprehensively reviewed the mechanisms, applications, drawbacks, and safety assessment of emerging NTE technologies and their combinative effects in the last 5 years, emphasizing their efficacy in improving agro-byproduct polyphenols' extraction. According to the review, incorporating cutting-edge NTE might promote the extraction of more phenolic extract from agro-byproducts due to numerous benefits, such as increased extractability, preserved thermo-sensitive phenolics, and low energy consumption. The next five years should investigate combined novel NTE technologies as they increase extractability. Besides, more research must be done on extracting free and bound phenolics, phenolic acids, flavonoids, and lignans from agro by-products. Finally, the safety of the extraction technology on the polyphenolic extract needs a lot of studies (in vivo and in vitro), and their mechanisms need to be explored. [ABSTRACT FROM AUTHOR]

Concerning the high impact of climatic change in the environment, the scientific community has focused on a circular economy perspective and the revalorization of waste generated by the food industry for bioactive uses. These applications are possible due to the presence of bioactive compounds in these food wastes. In this sense, phenolic compounds highlight for their positive health implications, as they possess potent activity to prevent diseases such as cancer, inflammation and obesity, among others. For this purpose, the optimized extraction of these target compounds from by-products with a novel green chemistry approach, by using environmentally clean and friendly extraction techniques, commonly known as green extractions, as well as those permitted in foods and safe for health (GRAS solvents) is commonly applied. Following this research line, a systematic review was conducted using different databases (Web of Science, PubMed and Scopus) following PRISMA guidelines to assess the optimization of different green and GRAS solvent extraction techniques from food by-products, the best extraction conditions, as well as the experimental design applied to obtained maximum amounts of the compounds of interest, considering the research published to date. Thus, 67 studies of 282 records identified met the inclusion criteria. A distinction has been made between the different technologies used in the extraction processes, paying special attention to the experimental designs applied and the optimized independent variables. Finally, a quantitative and qualitative comparison was made between the different matrices studied. • Recent advances regarding green extraction techniques were analysed. • The applicability to recover polyphenols from food by-products was disclosed. • The main experimental designs and optimized variables used were presented. • A special focus on analytical techniques for phenolic characterization was paid. [ABSTRACT FROM AUTHOR]

Extraction of bioactive compounds from beet leaves was studied for the valorization of this by-product. The objective of this work was to optimize the extraction of total phenolic compounds (TPC), betacyanins (BC) and betaxanthins (BX) from beet leaves through a liquid: solid process with low environmental impact. For this propose, kinetic aspects of the extraction process at 30 and 80 °C were evaluated, finding that times higher than 60 min were unfavourable for betalainic pigments since degradation was observed. Thereafter a Plackett–Burman design was applied to study the effect of several extraction variables on the efficiency of the process. Accordingly, temperature, %EtOH and solid:liquid ratio were selected as the most significant variables for a further optimization. Finally, Response Surface Methodology was employed in order to simultaneously maximize the three responses. The extraction conditions that achieve this goal were: 61 °C, 80% EtOH and r of 1:10, under which the bioactive concentrations were: 31.7 mg AG/g DM, 0.78 mg/g DM, 2.17 mg/g DM for TPC, BC and BX, respectively. The study proposes a simple and reasonably efficient method to produce a rich in phenolics, bright red–purple extract, which can be later processed to be used in several applications for the food industry. [ABSTRACT FROM AUTHOR]

Nowadays, green extraction processes are focused on the development of new strategies to achieve sustainable separation processes, promoting the use of alternative solvents from renewable sources. Green solvents have risen as an option that can replace petroleum based solvents, however, they should retain the same extraction properties and technological features. The choice of the solvent is a crucial step in the solvent-substitution process, so Hansen solubility parameters (HSP) have been successfully used as a real decision-making tool. For the first time, this work aims to give an overview of HSP as solvent selection tool for extraction of bioactive compounds from natural products. It includes a brief description about the emerging green solvents extraction, the HSP theory and an updated discussion of the most recent publications (from 2009 till January 2019). Finally, some concluding remarks about the importance of using this solvent selection approach in the near future are included. • Hansen solubility parameters is used as solvent selection tool for green extraction. • In the last 10 years, there has been a notably increase on HSP research publications. • Emerging extraction technologies have been employed Hansen approach with success. • Solubility of terpenes, phenolic compounds and fatty acids have been predicted by HSP. • COSMO-RS is another powerful approach employed to understand solubility mechanism. [ABSTRACT FROM AUTHOR]

Although the waste pomegranate peel (WPP) is a popular antioxidant source, pomegranate antioxidant extracts available in the market lack key antioxidant "punicalagin". Commercial production of pomegranate antioxidant extracts employ energy demanding drying of WPP followed by long hour extraction (detrimental to punicalagin) with organic solvents hazardous to the environment and human health that require stringent solvent recovery and disposal. Therefore, a fast and eco-friendly method based on aqueous ball milling (at pH 7 and 40 °C) without using hazardous reagent was developed to extract punicalagin enriched phenolics directly from fresh WPP. The systematic study of the combinations of ball milling time and liquid: solid ratio led to the highest recovery of phenolics (11–11.7 g 100 g−1 DW of WPP of wonderful and Ruby cultivar) containing 8.6–9.5 g punicalagin with highest antioxidant activity after 10 min ball milling with aqueous buffer at 15 mL g−1 liquid:solid ratio. The ball milling at these conditions using conventional organic solvents (methanol, ethanol, acetone, and ethyl acetate) yielded lower recoveries of total phenolics (4–11 g 100 g−1 DW of WPP) containing only 0.6–2.6 g punicalagin. The aqueous ball milling was also more rapid and efficient for the extraction of total phenolics and punicalagin than the ultrasound-assisted and Soxhlet extraction with methanol and aqueous buffer. Remarkably, the punicalagin content of the phenolic extract (70% w/w) obtained by aqueous ball milling is significantly higher compared to the punicalagin content (10–30% w/w) of commercially available pomegranate phenolic extracts. This extract also showed excellent storage stability as evident from no change in its punicalagin content even after 36 days of storage at 20 °C. Image 1 • Very fast recovery of punicalagin enriched phenolics was obtained from WPP. • The method is very simple, green, and has high punicalagin recovery efficiency. • Phenolic extract contained higher amount of punicalagin than commercial extracts. • Punicalagin yield by conventional solvents and methods was lower than ball milling. [ABSTRACT FROM AUTHOR]

Summary: Rice bran, the industry byproduct, contains high levels of phenolic compounds. Based on glycerol, a green recovery of phenolics from rice bran was proposed. Extraction temperature (X1), glycerol concentration (X2) and liquid‐to‐solid ratio (X3) were optimised by response surface methodology. Basic physical properties, that is, viscosity, conductivity, density were analysed and UPLC‐Triple‐TOF/MS method was applied for phenolic identification. Results showed the optimum conditions were X1 = 66.76 °C, X2 = 19.47% and X3 = 32.92 mL g−1. Under these conditions, the recovery yield in total polyphenols was 708.58 ± 12.36 mg GAE/100 g DW. Moreover, the recovery capacity of phenolic compounds was significantly correlated with viscosity, conductivity and density of glycerol solution. Under the optimal conditions, totals of thirteen phenolic compounds were identified and phenolic acids (4‐hydroxybenzoic acid, vanillic acid, syringic acid, 4‐coumaric acid, ferulic acid and salicylic acid) were quantified. These results demonstrate glycerol can serve as an ideal green solvent to recover phenolic compounds from rice bran. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the effects of natural deep eutectic solvents (NADESs) on extraction efficiency and antioxidant activities of phenolic compounds from Toona sinensis seeds (TSSs) compared with ethanol and water extraction methods. The single factor experiment was employed to optimize the extraction conditions of TSSs phenolic compounds on NADESs. Results indicate that the NADES of choline chloride-oxalic acid (CC-OA) with a molar ratio of 2:1 (solid/liquid ratio: 1:90 (m/v), extraction time: 30 min) showed the highest total phenolic content (32.58 mg GAE/g DW) and antioxidant activities (DPPH radical scavenging activity: 95.94%) compared with ethanol or water extraction. In addition, 15 main phenolic compounds were identified in the extracts of CC-OA solvent, while only 9 and 6 main compounds were identified in the extracts of ethanol and water solvents, respectively. The molecular dynamic simulation result illustrates that the high extraction efficiency of the NADES mainly attributing to their high compatibility as well as hydrogen interaction between ellagic acid (the main polyphenol in TSSs) and CC-OA solvent. In summary, the NADES (CC-OA at the ratio of 2:1) showed superior extraction efficiency on TSSs phenolic compound compared with ethanol or water extraction which could be an environmentally friendly method for the high-value utilization of TSSs. [ABSTRACT FROM AUTHOR]