Recovery Of Phenolic Compounds Research Articles

Recovery of phenolic compounds from wine lees using green processing: Identifying target molecules and assessing membrane ultrafiltration performance

Winery wastes are rich in polyphenols with high added value to be used in cosmetics, pharmaceuticals, and food products. This work aims at recovering and purifying the polyphenolic fraction occurring in the malolactic fermentation lees generated during the production of Albariño wines. Phenolic acids, flavonoids, and related compounds were recovered from this oenological waste by green liquid extraction using water as the solvent. The resulting extract solution was microfiltered to remove microparticles and further treated by ultrafiltration (UF) using membranes of 30 kDa and 5 kDa molecular weight cut-offs (MWCOs). The feed sample and the filtrate and retentate solutions from each membrane system were analyzed by reversed-phase liquid chromatography (HPLC) with UV and mass spectrometric (MS) detection. The most abundant polyphenols in the extracts were identified and quantified, namely: caftaric acid with a concentration of 200 µg g−1 and trans-coutaric acid, cis-coutaric acid, gallic acid, and astilbin with concentrations between 15 and 40 µg g−1. Other minor phenolic acids and flavanols were also found. The UF process using the 30 kDa membrane did not modify the extract composition, but filtration through the 5 kDa poly-acrylonitrile membrane elicited a decrease in polyphenolic content. Hence, the 30 kDa membrane was recommended to further pre-process the extracts. The combined extraction and purification process presented here is environmentally friendly and demonstrates that malolactic fermentation lees of Albariño wines are a valuable source of phenolic compounds, especially phenolic acids.

Management of reject streams from hybrid membrane processes applied to phenolic compounds removal from olive mill wastewater by adsorption/desorption and biological processes

This work studies the valorisation of the concentrates obtained through membrane processes for the purification of olive oil washing wastewater (OOWW). The adsorption with resins/desorption process, followed by a biological treatment with sequencing batch reactor SBRs. Three different wastewater samples were treated: an ultrafiltration reject stream (UF-R), with a high organic load and low content of phenolic compounds; a nanofiltration reject stream (NF-R), which rich in phenolic compounds and with medium organic load; a stream concentrated by forward osmosis (FO-C) with high organic content and concentration of phenolic compounds. Through the adsorption/desorption process, it was possible to recover 90 % and 73 %, which corresponds to 1.69 and 1.66 g∙L−1 of the total phenolic compounds reject streams of NF-R and FO-C, respectively. With the SBRs, it was possible to eliminate around 80 % of the organic matter present in the effluent of adsorption, and also 90 % of the remaining phenolic compounds in the case of UF-R. The results obtained are promising since, on the one hand, a high recovery of phenolic compounds was achieved and, on the other hand, a large part of the organic matter of the remaining streams after adsorption was eliminated. In this way, a solution for the management of the membrane reject streams is proposed, allowing a circular economy in the wastewater treatment of olive oil processing.

Using biobased solvents for the extraction of phenolic compounds from kiwifruit industry waste

Valorization of wastes rich in valuable compounds is one of the most relevant topics in biorefinery and circular economy. Kiwifruit industry wastes are a potential source of bioactive compounds, such as phenolic compounds, which, in turn, exhibit many biological activities with potential health benefits. With the aim of developing a green approach for the valorization of kiwifruit waste, a study combining biobased solvents, and alternative extraction techniques for the recovery of phenolic compounds from by-products of kiwifruits (Actinidia deliciosa) ‘Hayward’ are presented. First, a pre-selection of the most suitable by-product for the recovery of phenolic compounds was done, being the peels the most promising. After, extractions using different biobased solvents mixtures with ethanol and/or water, was carried out. Gamma-valerolactone (GVL) mixtures yielded extracts with the highest phenolic compounds and antioxidant activity levels. The composition of GVL mixtures was optimized to GVL:ethanol in a ratio of 7:3 (wt/wt). Response surface methodology was used to optimize the operating conditions of different extraction techniques namely, conventional extraction and alternative techniques of ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE). MAE has shown to be the most promising technique to obtain an extract with high levels of phenolic compounds (TPC: 29.7 ± 0.6 mg GAE/g DW; epicatechin derivatives as the main constituents, achieving a total of 2.295 ± 0.005 mg/g DW) and the highest antioxidant activity (FRAP: 87 ± 4 mg TE/g DW, ABTS: 131 ± 1 mg TE/g DW), in a shorter extraction time, as well as, when considering the estimated costs of the extraction processes. The results obtained showed the potential of using bio-based solvents (i.e. GVL) especially combined with alternative extraction techniques, to efficiently extract phenolic compounds from kiwifruit peels, paving the way for their use in the valorization of other waste rich in high-value compounds.

Evaluation of Pulsed Electric Field-Assisted Extraction on the Microstructure and Recovery of Nutrients and Bioactive Compounds from Mushroom (Agaricus bisporus)

Pulsed electric field (PEF) is a sustainable innovative technology that allows for the recovery of nutrients and bioactive compounds from vegetable matrices. A. bisporus was chosen for its nutritional value and the effect of PEF pretreatment was evaluated using different conditions of electric field (2–3 kV/cm), specific energy (50–200 kJ/kg) and extraction time (0–6 h) to obtain the best conditions for nutrient and bioactive compound extraction. Spectrophotometric methods were used to evaluate the different compounds, along with an analysis of mineral content by inductively coupled plasma mass spectrometry (ICP-MS) and the surface was evaluated using scanning electron microscopy (SEM). In addition, the results were compared with those obtained by conventional extraction (under constant shaking without PEF pretreatment). After evaluating the extractions, the best extraction conditions were 2.5 kV/cm, 50 kJ/kg and 6 h which showed that PEF extraction increased the recovery of total phenolic compounds in 96.86%, carbohydrates in 105.28%, proteins in 11.29%, and minerals such as P, Mg, Fe and Se. These results indicate that PEF pretreatment is a promising sustainable technology to improve the extraction of compounds and minerals from mushrooms showing microporation on the surface, positioning them as a source of compounds of great nutritional interest.

Deep Eutectic Solvents as a Green Tool for the Extraction of Bioactive Phenolic Compounds from Avocado Peels.

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.

Evaluation of mixtures of maltodextrin and gum Arabic for the encapsulation of Andean blueberry (Vaccinium meridionale) juice by freeze–drying

SummaryAndean blueberry fruit is considered a source of bioactive compounds. However, its industrial applications as an ingredient are limited due to its low stability. In this work, Andean blueberry juice powders were obtained via freeze–drying. The effects of maltodextrin (MD) and gum Arabic (GA) as encapsulating agents were evaluated on the morphological, physicochemical, and rheological quality of the products, as well as in terms of the recovery of phenolic compounds. All the freeze–dried powders featured typical macroscopic and microscopic morphology, low moisture content (<5%) and water activity (aw < 0.3), high water solubility (>91%) and good flowability. The encapsulation with MD overall favoured higher water activity, solubility and flowability, and a significant increase of total phenolics recovery in the juice powders, compared with GA or GA:MD mixtures. The results showed that encapsulation by freeze–drying enables the production of Andean blueberry juice powders with suitable technological characteristics and potential as bioactive ingredients.

Recovery of phenolic compounds from purple onion peel using bio‐based solvents: Thermal degradation kinetics and color stability of anthocyanins

AbstractThe aim of this study was to evaluate the influence of bio‐based solvent (ethanol, water, and acetic acid) on the extraction of phenolic (TPC), anthocyanins (TAC), and flavonoids (TFC) from purple onion peel and also analyze the effects of storage temperature on the kinetics of anthocyanin degradation and color stability of the phenolic‐rich extract obtained. The purple onion extract obtained with 60% ethanol (E60E) showed, respectively, TPC, TAC, and TFC about 3.4, 2.5, and 4.45 times higher than the other solvents used. E60E showed higher antioxidant and antibacterial potential compared to other solvents. E60E was stored at 4, 25, and 38°C, a half‐life of 285, 48.81, and 21.80 days was obtained, respectively. The degradation of anthocyanins in E60E occurred by an endothermic and non‐spontaneous reaction with activation energy of 54.65 kJ mol−1, being strongly related to the thermal sensitivity of the phenolic compound.Novelty impact statementPurple onion peel is a food waste rich in bioactive compounds, being a low‐cost alternative for obtaining extracts with coloring and functional potential. The results of this study indicate that the purple onion peel is an excellent source for obtaining a phenolic‐rich extract with high antioxidant and antimicrobial activity. The anthocyanin, color, and stability index indicates that the extract can applied in several biosectors (e.g., pharmaceutical, cosmetic, and food industries).

Recent Technological Advances in Phenolic Compounds Recovery and Applications: Source of Nutraceuticals for the Management of Diabetes

Background: Phenolic compounds are food-derived bioactive compounds well-known for their antioxidant and anti-inflammatory properties. They are in the spotlight for the management of diabetes due to their positive effects on glucose homeostasis. Materials and methods: We have performed a literature review on the main topics related to the application of phenolic compounds as functional food ingredients. This includes extraction and purification from vegetable sources and agro-industrial by-products, encapsulation to improve their solubility and bioavailability, and preclinical and clinical evidence linking these compounds with anti-diabetic activity. Objectives: (1) provide an understanding of the role of phenolic compounds on diabetes; (2) identify green technologies for phenolic compounds extraction from agri-food by-products following a biorefinery scheme; (3) underline the relevance of encapsulation techniques using nanotechnology to improve their bioavailability; (4) discuss the therapeutic efficacy of polyphenols. Results: This review compiles recent relevant research on phenolic compounds extraction from renewable resources, their purification from agri-food by-products, and encapsulation strategies using eco-friendly processes. It also highlights the preclinical and clinical evidence on phenolic compounds’ antidiabetic activity, giving insight into their mechanisms of action. Conclusions: This review explores the latest advances in polyphenols and how their benefits in glucose homeostasis can be applied toward improving the health of patients with diabetes and related conditions.

Enzyme-Assisted Extraction of Phenolics from Capparis spinosa Fruit: Modeling and Optimization of the Process by RSM and ANN.

The current study intends to appraise the effect of enzyme complexes on the recovery of phenolics from Capparis spinosa fruit extract using the response surface methodology (RSM) and artificial neural networking (ANN). Enzymatic treatment of C. spinosa fruit extract was optimized under a set of conditions (enzyme concentration, pH, temperature, and time) against each enzyme formulation such as Kemzyme Plus Dry, Natuzyme, and Zympex-014. The extract yield observed for Kemzyme Plus Dry (42.00%) was noted to be higher than those for Zympex-014 (39.80%) and Natuzyme (38.50%). Based on the higher results, the values of Kemzyme Plus Dry-based extract were further employed in different parameters of RSM. The F-value (16.03) and p-values (<0.05) implied that the selected model is significant. Similarly, the higher values for the coefficient of determination (R2) at 0.9740 and adjusted R2 (adj. R2) at 0.9132 indicated that the model is significant in relation to given experimental parameters. ANN-predicted values were very close to the experimental values, which demonstrated the applicability of the ANN model. Antioxidant activities also exhibited profound results in terms of total phenolic content values (24.76 mg GAE/g), total flavonoid content values (24.56 mg CE/g), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (IC50) (5.12 mg/mL). Scanning electron microscopy revealed that after enzymatic hydrolysis, the cell walls were broken as compared with nonhydrolyzed materials. Five phenolics, namely, quercetin, m-coumaric acid, sinapic acid, kaempferol, and p-coumaric acid, were identified from C. spinosa extract by gas chromatography–mass spectrometry (GC/MS). The results of this study reveal that the proposed optimization techniques, using Kemzyme Plus Dry among others, had a positive effect on the recovery of phenolic bioactive compounds and thus increased the antioxidant potential of C. spinosa fruit extract.

Recovery of Bioactive Extracts from Olive Leaves Using Conventional and Microwave-Assisted Extraction with Classical and Deep Eutectic Solvents

The recovery of phenolic compounds from olive leaves (Olea europaea L.) has received special attention due to their significant potential for applications in food, nutraceuticals, cosmetics, and pharmaceuticals. In this work, the extraction of the phenolic compounds from olive leaves was examined by means of conventional extraction and microwave-assisted extraction (MAE) using nontoxic common solvents such as ethanol and water as well as using promising environmentally friendly, Deep Eutectic Solvents (DESs) and their mixtures with ethanol or water. The effects of the various parameters that likely govern the extractability of the bioactive compounds of olive leaves (OL), such as the solvent type, temperature, and biomass to solvent mass ratio, were studied and evaluated with regard to the oleuropein and hydroxytyrosol content, antioxidant activity, and total phenolic content of the extracts. The study also explores the effects of the microwave-assisted extraction parameters, namely irradiation power and time, on the total phenolic content and antioxidant activity of the extracts. The findings of this work suggest that among the solvents studied, the solvent mixture consisting of the DES choline chloride:acetic acid with a molar ratio of 1:2 and ethanol (80:20 w/w) is highly effective in recovering extracts rich in phenolic compounds and with significant antioxidant activity. Moreover, it is demonstrated that the MAE method allows for the recovery of bioactive compounds in a very short processing time.

Phenolic compounds and antioxidant activity of Lippia graveolens Kunth residual leaves fermented by two filamentous fungal strains in solid-state process

The residual leaves from essential oil extraction from Mexican oregano (Lippia graveolens) have a potential as a source of bioactive molecules (e.x. flavonoids) that could be extracted by solid state fermentation (SSF) process. In this study, the residual leaves were subjected to a SSF (120 h) by two microorganism Trichoderma harzianum and Rhizopus oryzae evaluating the phenolic compounds (Total polyphenols and flavonoids), the antioxidant activity (DPPH● / FRAP), the bioactivities (α-amylase inhibition and antimicrobial against Escherichia coli), the cytotoxic effect (erythrocytes) and a characterization (HPLC-MS). The results showed that the total polyphenols for T.harzarium did not show statistical differences (first 48 h), and R. oryzae fermentation obtained a higher context (48 h). Also, the higher flavonoid release was present at 48 and 96 h (T. harzianum and R. oryzae). The antioxidant activity decreased in the last fermentation hours, the a-amylase reported a higher inhibition value (29.97 ± 1.97 %) and antimicrobial capacities; R. oryzae (96 h) did not register a cytotoxic effect. The characterization determined the presence of valuable molecules as ferulic acid 4-O-glucoside, phloridzin and luteolin. The fermentation allowed the recovery of bioactive phenolic compounds that could be an alternative for the revalorization of oregano waste.

Optimization and modelling in flavonoid and phenolic compounds recovery from peanut skin by subcritical water

Optimization and modelling in flavonoid and phenolic compounds recovery from peanut skin by subcritical water

Green extraction of phenolic compounds and carrageenan from the red alga Kappaphycus alvarezii

Kappaphycus alvarezii (KA) is a widespread worldwide alga, and one of the main industrial sources of carrageenan. Besides, KA biomass also contains other substances such as phenolic compounds and fatty acids that can be recovered by several methods. Then, this work aimed to investigate the eco-friendly methods, for the recovery of fatty acids, phenolics, and carrageenan fractions. The eco-friendly methods are faster, produce higher yields, and can be cost-effective in comparison with conventional methods. The performance of the eco-friendly methods (supercritical fluid, pressurized liquid, microwave assisted, and high-pressure carrageenan extractions) was compared with conventional techniques (maceration or Soxhlet) in terms of yield, chemical profile by gas and liquid chromatography, total phenolic content (TPC), antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and Ferric reducing antioxidant power (FRAP) procedures, viscosity and gel strength of the carrageenan fraction. The results showed pressurized liquid extraction samples with the highest antioxidant potential and TPC (up to 2 to 4 times higher than conventional). Besides, the carrageenan fraction was efficiently recovered by microwave assisted extraction (MAE) and by pressurized-water carrageenan extraction (PWCE), and the samples presented viscosity and gel strength similar to that obtained by water maceration. • Phenolic compounds were firstly quantified from Kappaphycus Alvarezii (KA). • Green methods were applied to obtain carrageenan and phenolic compounds from KA. • High pressure methods were adequate for the recovery of carrageenan and phenolic compounds. • The carrageenan physical properties were similar to conventional extraction.

Solid State Fermentation of Olive Leaves as a Promising Technology to Obtain Hydroxytyrosol and Elenolic Acid Derivatives Enriched Extracts.

Extraction of valuable bioactive compounds from olive leaves is a hot topic and the use of sustainable and green technologies is mandatory in terms of circular economy. In this way, the use of fermentation technologies showed very interesting results in terms of phenolic compound recovery. Because of that in this work the use of solid state fermentations, as valuable tool to improve the phenolic extraction has been checked. Aspergillus oryzae (in mycelium and spore form), Aspergillus awamori and Aspergillus niger were used as fermentation microrganisms. Phenolic compounds were determined by HPLC-ESI-TOF-MS and, to our knowledge, new compounds have been tentatively identified in olive leaves. Fermentation using mycelium of Aspergillus awamori, Aspergillus niger and Aspergillus oryzae were effective to increase both hydroxytyrosol and elenolic acid derivatives whereas the use of spores of Aspergillus oryzae caused a loss of hydroxytyrosoyl derivatives, contrary the content of elenolic derivatives are comparable with the other fermentation treatments and higher than control. The proposed fermentation processes using the mycelium of Aspergillus awamori, Aspergillus niger and Aspergillus oryzae lead to an increase the hydroxytyrosyl and elenolic acid derivatives and could be used at industrial scale to obtain enriched extracts.

Ultrasound-assisted natural deep eutectic solvent extraction of phenolic compounds from apple pomace

ABSTRACT In this study, an environmentally friendly and efficient method based on natural deep eutectic solvent (NADES) in combination with ultrasound-assisted extraction was used for the recovery of phenolic compounds from apple pomace. Acidic, alkaline, sugar-based and polyol-based NADESs were examined for extraction of total phenolic content from apple pomace under different conditions.NADES type, biomass percentage, extraction temperature, extraction time and water content were the testing parameters. NADES type and water content of the solvent were the most important parameters that affected the extraction yield. The most effective NADESs were sugar-based NADESs, which were followed by acidic NADESs. Up to 9.47 mgGAE/gapple pomacewas recovered from apple pomace with glucose:sucrose:water. The highest total flavonoid content was obtained with choline chloride:urea as 17.30 mgEPE/gapple pomace. On the other hand, NADES composed of choline chloride – lactic acid was found to exhibit a significant antioxidant activity. The novelty of this article is the investigation of acidic, alkaline, sugar-based and polyol-based NADESs in the recovery of phenolic compounds from apple pomace using ultrasound-assisted extraction, for the first time in the literature. The antioxidant activity of extracts were also explained in combination with that of NADESs.

Development of an Effective Sonotrode Based Extraction Technique for the Recovery of Phenolic Compounds with Antioxidant Activities in Cherimoya Leaves.

The leaves of Annona cherimola Mill (cherimoya) are a potential source of phenolic compounds that have been shown to have beneficial properties. Therefore, this study focuses on establishing an ultrasonic-assisted extraction of phenolic compounds in cherimoya leaves using a sonotrode. For that purpose, a Box-Behnken design based on a response surface methodology (RSM) was used to optimize factors, such as amplitude, extraction time and solvent composition to obtain the maximum content of phenolic compounds by HPLC-MS and the maximum in-vitro antioxidant activity by DPPH, ABTS and FRAP assays in ‘Fino de Jete’ cherimoya leaves. The optimal conditions were 70% amplitude, 10 min and 40:60 ethanol/water (EtOH/H2O) (v/v). The results obtained under these optimum conditions by using a sonotrode were compared with those from an ultrasonic bath; briefly, recovery of phenolic compounds by sonotrode was 2.3 times higher than a bath. Therefore, these optimal conditions were applied to different varieties ‘Campas’, ‘Fino de Jete’ and ‘Negrito Joven’ harvested in the Tropical Coast of Granada (Spain). A total of 39 phenolic compounds were determined in these cherimoya leaf extracts, 24 phenolic compounds by HPLC-MS and 15 proanthocianidins by HPLC-FLD. 5-p-coumaroylquinic acid, lathyroside-7-O-α-l-rhamnopyranoside and quercetin hexose acetate were first identified in cherimoya leaves. The most concentrated phenolic compounds were the flavonoids, such as rutin and quercetin hexoside and proanthocyanidins including monomers. Almost no significant differences in the phenolic content in these cultivars were found (11–13 mg/g d.w. for phenolic compounds and 11–20 mg/g d.w. for proanthocyanidins). In addition, sonotrode ultrasonic-assisted extraction has been shown to be an efficient extraction technique in the phenolic recovery from cherimoya leaves that could be implemented on an industrial scale.

Valorization of SCG through Extraction of Phenolic Compounds and Synthesis of New Biosorbent

Coffee is considered to be one of the most renowned beverages and it is the second-most consumed product worldwide. Spent coffee grounds (SCGs) are the primary solid residue, which are generated during the coffee powder brewing in hot water or steam. The formation of huge amounts of these byproducts poses a severe threat to the environment, due to their organic nature and their high phenolic compounds concentration. Nevertheless, the latter are characterized as bioactive compounds with high antioxidant activity turning SCG into an economical raw matrix for the isolation of valuable components. Phenolic compounds that can be isolated from coffee byproducts can be potentially used as natural antioxidants in food, pharmaceutical, and cosmetics industries. Thus, the research community has focused its efforts on the optimization of phenolics extraction by the development of novel environmentally friendly techniques except for conventional maceration extraction using organic solvents. The objective of this review is to present an inclusive summary of the revalorization of SCGs and the potential uses of those solid residues through the recovery of phenolic compounds or the use of untreated or treated SCGs as biosorbents of valuable compounds from other food industry byproducts.

Integration of solvent extraction and membrane processes to produce an oleuropein extract from olive leaves

The integration of solvent extraction and membrane separation technology was used to recover and concentrate oleuropein from olive leaves. In this study, the effect of extraction solvent (type, composition) on the content of total phenolic compounds (TPC) extracted from olive leaves was investigated. Experimental results showed that ethanol:water, 75 %/25 % (v/v), gives the highest TPC. Thus, to establish the parameters to obtain hydroethanolic olive leaves extract with the highest content of total phenolic compounds, a Central Composite Design was performed. The extract obtained at 50 °C for 90 min, within 0.03 g/ml, was subjected to crossflow ultrafiltration (UF) to remove suspended solids in the feed and to reduce fouling phenomena, followed by a stirred dead-end nanofiltration (NF) using a commercial flat sheet membrane at different pressure (10, 20 and 30 bar). The nanofiltration (at 30 bar) showed a high rejection coefficient towards phenolic compounds and flavonoid contents. Fractions coming from UF and NF (at 30 bar) revealed that the highest content of oleuropein was 119.01 mg/g corresponding to NF retentate, high antioxidant capacity (DPPH method). Conductivity, sanity, turbidity, pH, TDS, and TSS of different fractions were also determined. It can be concluded that the integration of solvent extraction and membrane separation technology is efficient for the recovery and concentration of oleuropein and phenolic compounds from olive leaves. The obtained concentrate is of interest for preparing formulations to be used in the food, cosmetic and pharmaceutical industries.

Mango ‘criollo’ by-products as a source of polyphenols with antioxidant capacity. Ultrasound assisted extraction evaluated by response surface methodology and HPLC-ESI-QTOF-MS/MS characterization

Ultrasound assisted extraction (UAE) was evaluated as a green procedure for the recovery of phenolic compounds with antioxidant capacity from underutilized mango 'criollo' (peel, pulp and seed). Magnetic stirred was performed as conventional extraction. Response surface methodology using a three-factor (% ethanol, amplitude and time) central composite design was used to maximize the extraction for total phenolic compounds (TPC), total flavonoids and antioxidant capacity. The operational conditions to maximize extraction were: peel, 46% ethanol/amplitude 60% (36 µm)/6.5 min; pulp, 25% ethanol/amplitude 75% (45 µm)/30 min; seed 49% ethanol/100% (60 µm) amplitude/20 min. The phenolic composition of the optimized extracts was characterized by HPLC-QTOF-MS/MS and 45 compounds were tentatively identified as xanthones (mangiferin), flavonoids (quercetin), ellagic acid, benzophenones (maclurin), gallate derivatives and gallotannins. UAE increased TPC extraction (33%); interestingly mangiferin extraction increased 53% in peel, similarly, ellagic acid increased up to 2.5 and 4.4 times in peel and seed extracts.

Green manufacturing of high-value extracts from milk thistle seeds: Parameters that affect the supercritical CO2 extraction process

The aim of this study was to provide insights into parameters that affect the oil extraction from an industrially valuable raw material (milk thistle) using green solvent supercritical CO2. The effect of plant origin, cultivation year, and seeds storage on extraction yield has been explored. Furthermore, the effects of high-pressure unit design and initial plant material amount have been examined. Pressure (200–450 bar) and temperature (40–80 °C) have been tested to improve the recovery of essential fatty acids and phenolic compounds. Moreover, solid residues after the material pretreatment and supercritical CO2 extraction served as the substrates for waste valorization. The characterization of obtained high-value extracts has been carried out by chromatographic (using gas chromatographs combined with mass spectrometer and flame ionization detection) and spectrophotometric assays (for total phenolic and flavonoid compounds as well as a radical scavenging ability). It was shown that the tested supercritical CO2 extraction process parameters determined extraction kinetics and allowed the extract separation from raw milk thistle seeds and waste material (3–32 mass %) rich in linoleic acid (up to 515 mg/g) and total phenolic compounds (up to 30 mg GAE/g).