Special Issue "Extraction Optimization Processes of Antioxidants"

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Biological Processes and Systems".

Deadline for manuscript submissions: closed (20 November 2021).

Special Issue Editors

Dr. Francesca Blasi
E-Mail Website
Guest Editor
Department of Pharmaceutical Sciences, University of Perugia, Via San Costanzo, 06126 Perugia, Italy
Interests: lipids; antioxidants; gas-chromatography; vegetable extracts
Dr. Lina Cossignani
E-Mail Website
Guest Editor
Department of Pharmaceutical Sciences, University of Perugia, 06126 Perugia, Italy
Interests: food lipids; food analysis; antioxidants; food waste; functional foods; nutraceuticals
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

It is scientifically evident that the increased consumption of antioxidant-rich foods is associated with a reduction of chronic disease risk. The use of natural antioxidants, such as polyphenols, has increased in the food, cosmetic, and pharmaceutical fields. Since some synthetic antioxidants show negative health effects, at present, there is the necessity to replace them with natural compounds. It has been reported that that vegetable extracts can also be used as an alternative for the treatment of different diseases, among them obesity and diabetes. However, there are various and not universally accepted methods for extracting antioxidant compounds from foods and waste (i.e., fruits, herbs, legumes, berries, shrubs, algae, roots). Usually, these methods are based on the use of pure solvents or mixtures with different polarities and should take into consideration the chemical structure of the antioxidants and the different structural and compositive characteristics of vegetable matrices. Based on this consideration, special attention must be given to the research of the best conditions for maximizing antioxidant extraction from vegetable foods and byproducts, focusing research on the development of new optimized extraction methodologies, also based on response surface methodology.

This Special Issue on “Extraction Optimization Processes of Antioxidants” aims to curate novel advances in the development and application of sustainable extraction methods also to address the recovery of waste products. Topics include but are not limited to:

  • Development of new extraction methods to improve yield and selectivity of processes;
  • Chemical–analytical characterization and evaluation of bioactivity of vegetable extracts;
  • Optimization of extraction process to drive on-large scale methods toward sustainability;
  • Development of green innovative process to obtain the recovery of waste products.

Dr. Francesca Blasi
Prof. Lina Cossignani
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • bioactive compounds
  • biological activity
  • enzymes
  • innovative processes
  • waste
  • sustainability
  • response surface methodology
  • green chemistry
  • byproducts
  • analytical characterization

Published Papers (16 papers)

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Research

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Article
Olive Oil Dregs as a Novel Source of Natural Antioxidants: Extraction Optimization towards a Sustainable Process
Processes 2021, 9(6), 1064; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9061064 - 18 Jun 2021
Viewed by 467
Abstract
Olive oil dregs (OOD), which are an underutilized by-product from oil mills, were used for the extraction of antioxidant compounds. The residues from three oil mills located in Campania (Southern Italy) were extracted with acidified methanol, and hydroxytyrosol (HT) was the main phenolic [...] Read more.
Olive oil dregs (OOD), which are an underutilized by-product from oil mills, were used for the extraction of antioxidant compounds. The residues from three oil mills located in Campania (Southern Italy) were extracted with acidified methanol, and hydroxytyrosol (HT) was the main phenolic compound detected. Total phenolic content (TPC) and HT amount were measured. EVO Campania oil mill provided the residue with the highest TPC and HT quantities: 6.801 ± 0.159 mg Gallic Acid Equivalents (GAE)/g OOD and 519.865 ± 9.082 μg/g OOD, respectively. Eco-friendly extractions at different temperatures and times were performed on EVO Campania OOD, obtaining 9.122 ± 0.104 mg GAE/g OOD and 541.330 ± 64.087 μg/g OOD for TPC and HT, respectively, at 121 °C for 60 min. Radical Scavenging Activity (RSA), Superoxide Scavenging Activity (SSA), and Ferric Reducing Antioxidant Power (FRAP) were measured in OOD aqueous extracts. Extract prepared at 37 °C for 60 min showed the greatest RSA and SSA values (44.12 ± 1.82 and 75.72 ± 1.78, respectively), whereas extract prepared at 121 °C for 60 min exhibited the highest FRAP value (129.10 ± 10.49 μg Ascorbic Acid Equivalents (AAE)/mg). OOD extracts were able to protect sunflower oil from oxidation for 4 weeks at 65 °C. The overall results suggest that this novel residue can be usefully valorized by providing HT-rich extracts to use as antioxidant agents. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Composition and Antioxidant Activity, Supercritical Carbon Dioxide Extraction Extracts, and Residue after Extraction of Biologically Active Compounds from Freeze-Dried Tomato Matrix
Processes 2021, 9(3), 467; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9030467 - 05 Mar 2021
Cited by 2 | Viewed by 498
Abstract
Supercritical carbon dioxide extraction (SCE-CO2) is an attractive, green technology that is used for the recovery of biologically active compounds from plant material. The antioxidant potential of lipophilic fractions (extract obtained with SCE-CO2) and hydrophilic fractions (extracts obtained from [...] Read more.
Supercritical carbon dioxide extraction (SCE-CO2) is an attractive, green technology that is used for the recovery of biologically active compounds from plant material. The antioxidant potential of lipophilic fractions (extract obtained with SCE-CO2) and hydrophilic fractions (extracts obtained from the residue after extraction) obtained from a matrix of freeze-dried tomatoes (cvs. “Admiro” F1, “Jurgiai”, “Vilina”, “Pirmutis”, and “Skariai”) was assessed via different antioxidant activity methods. The total amount of polyphenols, carotenoids, and carotenoid isomers before and after SCE-CO2 extraction was also determined. To investigate the effect of the SCE-CO2 extract on the viability of cancer cells, rat glioblastoma C6 cells were chosen. The SCE-CO2 yielded an average of 800 mg of lipophilic fraction per 100 g of freeze-dried tomatoes. The ABTS•+ scavenging activity of the extract was 251 ± 3.4 µmol TE/g. After SCE-CO2 extraction, the DPPH-RSA of the freeze-dried tomato matrix was 7 to 12% higher. There was a strong positive correlation (R = 0.84) between the total polyphenolics content and the DPPH•-RSA of the tomato samples. The SCE-CO2 increased the radical scavenging activity of the extraction residue, indicating that a considerable fraction of the hydrophilic compounds with particular antioxidant capacity remain unextracted from the tomato matrix. Our results reveal the cytotoxic effect of lycopene extract rich in cis-isomers (62% cis-isomers of the total lycopene content) on rat glioblastoma C6 cells. The viability of the glioblastoma C6 cells significantly decreased (−42%) at a total lycopene concentration of 2.4 µM after 24 h of incubation. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Optimization and Comparison of Three Cell Disruption Processes on Lipid Extraction from Microalgae
Processes 2021, 9(2), 369; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9020369 - 17 Feb 2021
Cited by 3 | Viewed by 1556
Abstract
This study reports on the optimization of the operating conditions using response surface methodology and a comparative study of three promising technologies of cell disruption (bead milling, microwaves and ultrasound) to increase the lipid extraction from Nannochloropsis oceanica, Nannochloropsis gaditana and Tetraselmis [...] Read more.
This study reports on the optimization of the operating conditions using response surface methodology and a comparative study of three promising technologies of cell disruption (bead milling, microwaves and ultrasound) to increase the lipid extraction from Nannochloropsis oceanica, Nannochloropsis gaditana and Tetraselmis suecica. Central composite designs were used for the optimization of ultrasound and microwave processes. The performance of the cell disruption processes in breaking down microalgae cells is dependent on the strain of microalgae. Microwaves (91 °C for 25 min) were the most efficient for the recovery of lipids from N. oceanica, reaching a lipid content of 49.0% dry weight. For N. gaditana, ultrasound process (80% of amplitude for 30 min) was the most efficient in terms of lipid recovery (21.7% dry weight). The two aforementioned processes are ineffective in disturbing T. suecica whatever the operating conditions used. Only the bead milling process at low flow feed rate with 0.4 mm zirconia beads made it possible to extract 12.6% dry weight from T. suecica. The fatty acid profiles of N. oceanica and T. suecica are affected by the cell disruption process applied. The calculation of specific energy consumption has shown that this criterion should not be neglected. The choice of the most suitable cell disruption process can be defined according to numerous parameters such as the microalgae studied, the total lipid extracted, the fatty acids sought, or the energy consumption. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Effect of Storage Conditions and Time on the Polyphenol Content of Wheat Flours
Processes 2021, 9(2), 248; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9020248 - 29 Jan 2021
Viewed by 448
Abstract
Whole wheat flour possesses many nutritional properties because of its abundant bioactive components which are affected by cultivar, but little attention is paid to its relationship with storage conditions. In this study, phenolic extracts of whole wheat flour from four cultivars stored under [...] Read more.
Whole wheat flour possesses many nutritional properties because of its abundant bioactive components which are affected by cultivar, but little attention is paid to its relationship with storage conditions. In this study, phenolic extracts of whole wheat flour from four cultivars stored under different conditions (aerated and under vacuum) and different times (0, 2, 4, 8 weeks) were obtained. The total polyphenol (TPC) and flavonoid (TFC) contents, composition of phenolic acids, and antioxidant activities (AA) of phenolic extracts were evaluated. The results showed that Verna exhibited the highest levels of TPC, TFC, and AA for both storage conditions among the four cultivars. Moisture content, TFC, and AA fluctuated during storage. After 8 weeks, the TPC, TFC, and AA decreased with respect to Week 0 in all the cultivars. The TPC losses ranged between 16.39% and 20.88% and TFC losses from 14.08% to 31.18%. The AA losses were approximately 30% from the DPPH assay, but no significant losses were shown in the FRAP assay. However, these parameters were not distinctive between the two storage conditions. The wheat phenolic acid profiles were influenced more by storage time than storage conditions in all cultivars. Overall, the results validate the effect of the storage time on wheat polyphenol. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Ultrasound-Assisted Extraction of Antioxidants from Baccharis dracunculifolia and Green Propolis
Processes 2020, 8(12), 1530; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121530 - 25 Nov 2020
Viewed by 649
Abstract
Baccharis dracunculifolia or rosemary-of-field is the principal botanical source used by Africanized bees Apis mellifera L. to produce green propolis in Southeastern Brazil. The phenolic compounds present in the plant and green propolis have been reported to be responsible for biological activities such [...] Read more.
Baccharis dracunculifolia or rosemary-of-field is the principal botanical source used by Africanized bees Apis mellifera L. to produce green propolis in Southeastern Brazil. The phenolic compounds present in the plant and green propolis have been reported to be responsible for biological activities such as antioxidant capacity. This study aimed to optimize the ultrasound-assisted extraction of antioxidants compounds from rosemary-of-field using a central composite rotatable design (CCRD), and compare results to green propolis extract. An experimental design was performed to obtain responses of total phenolic content and antioxidant capacity. The results allowed observing that the optimum condition for both Baccharis dracunculifolia floral bud and raw green propolis antioxidant extraction was obtained with 99% ethanol solution. In this condition, Total Phenolic Content (TPC), Ferric Reducing Antioxidant Power (FRAP), and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) values were 612.14 mg GAE. g−1 sample, 534.39 µM ferrous sulfate g−1 sample, and 72.37 µmol TEAC. g−1 sample, respectively, for floral buds. These results have confirmed that optimization is a key step for effective and sustainable extraction processes to be feasible on an industrial scale. The proposed process can be easily adopted on a larger scale, as it uses very few inputs and presents straightforward steps, with the advantage of high efficiency in the extraction of phenolic compounds from the studied matrices compared to the results from the literature. The high concentration of antioxidants indicates that the products obtained can be considered as a sustainable bioactive source for food and cosmetic purposes. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Effect of Drying and Steeping Temperatures on the Phenolic Content, Antioxidant Activity, Aromatic Compounds and Sensory Properties of Cunila polyantha Benth. Infusions
Processes 2020, 8(11), 1378; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111378 - 30 Oct 2020
Viewed by 958
Abstract
Cunila polyantha Benth. (Lamiaceae), an aromatic plant endemic to Mexico, is used in traditional medicine as tea infusions. In this study, the effects of different drying and steeping temperatures on the phenolic content and composition, antioxidant activity, volatile composition, and sensory properties of [...] Read more.
Cunila polyantha Benth. (Lamiaceae), an aromatic plant endemic to Mexico, is used in traditional medicine as tea infusions. In this study, the effects of different drying and steeping temperatures on the phenolic content and composition, antioxidant activity, volatile composition, and sensory properties of C. polyantha infusions were determined. Commercial green tea (Camellia sinensis L. Kuntze) was used as a control. The phenolic compounds identified in the C. polyantha infusions by high-performance liquid chromatography (HPLC) include phenolic acids such as gallic acid, chlorogenic acid, caffeic acid, and p-coumaric acid, flavonoids such as epigallocatechin gallate, protocatechin, quercetin, and naringenin, as well as the phenolic aldehyde vanillin. The C. polyantha infusions showed scavenging activity of DPPH and ABTS•+ radicals as well as relevant antioxidant capacity, which was dependent on tea preparation conditions. A total of 46 volatile organic compounds (VOCs) were detected from the leaves and flowers of C. polyantha, while in the control group, a total of 30 VOCs were identified. Differences in consumer acceptability of C. polyantha infusions prepared at different conditions were observed. This research highlights the importance of linking sensory and chemical data to obtain the best sensorial quality and the optimal nutraceutical properties in C. polyantha infusions. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Effect of Heat Treatment and Light Exposure on the Antioxidant Activity of Flavonoids
Processes 2020, 8(9), 1078; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8091078 - 01 Sep 2020
Cited by 4 | Viewed by 1016
Abstract
The application of food processes can lead to a modification of both the structure and the activities of flavonoids. In this article, the effect of heat treatment and exposure to light on the antioxidant activity of 6 model flavonoid solutions (rutin, naringin, eriodictyol, [...] Read more.
The application of food processes can lead to a modification of both the structure and the activities of flavonoids. In this article, the effect of heat treatment and exposure to light on the antioxidant activity of 6 model flavonoid solutions (rutin, naringin, eriodictyol, mesquitol, luteolin, and luteolin 7-O-glucoside) was studied. The evolution of the antioxidant activity measured after heat treatment of 130 °C at 2 h and an exposure to visible light for 2 weeks is measured by the ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) method and represented by a new parameter called ΔTEAC. The model solution of Mesquitol showed the highest increase in ΔTEAC after a heat treatment, a value of 200 mM was obtained. The increase in ΔTEAC is always greater with thermal treatment than with light exposure. Thus, temperature and light lead to different degradation pathways of the flavonoid. In vivo measurements were carried out with solutions of naringin, erodictyol, and luteolin 7-O-glucoside. Heated solutions of flavonoids do not exhibit toxicity on cells. The specific activities of superoxide dismutase and glutathione peroxide have been determined and have shown an increased impact on the potential anti-cancer of these solutions by enhancing their cellular antioxidant activity, as well as modulation of the oxidative stress. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Effects of Blueberry and Black Carrot Extracts Addition on Antioxidant Properties and Protein-Precipitating Capacity of Ultrasound-Treated Cider
Processes 2020, 8(7), 812; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8070812 - 10 Jul 2020
Cited by 1 | Viewed by 714
Abstract
The results presented in this study highlight the level of total phenolic content (TPC), total flavonoid content (TFC) and protein-precipitating capacity (PPC) correlated with the antioxidant capacity of new cider varieties enriched with valuable bio compounds by the addition of blueberry and black [...] Read more.
The results presented in this study highlight the level of total phenolic content (TPC), total flavonoid content (TFC) and protein-precipitating capacity (PPC) correlated with the antioxidant capacity of new cider varieties enriched with valuable bio compounds by the addition of blueberry and black carrot extracts. The cider variants were treated with ultrasound (constant frequency of 20 kHz) at 20%, 30% and 40% amplitude (A) for two, five or seven minutes. TPC determination was performed by Folin–Ciocâlteu method and TFC was determined by an aluminum chloride colorimetric method. The antioxidant capacity was determined by ferric-reducing antioxidant power assay (FRAP), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity. The results showed that the antioxidant performance indicators (FRAP, ABTS and DPPH) were positively correlated with the TPC and TFC of the ultrasound-treated cider variants, suggesting that the content of these bio compounds may be improved by the treatments applied. The highest mean values for TPC and TFC were found in the cider variant enriched with black carrot extract (0.3%, v/v), subsequently ultrasound-treated (A20%, five minutes) Conclusively, the extracts used in this study could improve the antioxidant capacity of the cider, especially in case of variants ultrasound-treated. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Polyphenol Content and Biological Activities of Ruta graveolens L. and Artemisia abrotanum L. in Northern Saudi Arabia
Processes 2020, 8(5), 531; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8050531 - 30 Apr 2020
Cited by 3 | Viewed by 1268
Abstract
Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore, tentative high-performance liquid chromatography–diode array detection was used to analyze the polyphenol contents of leaf extracts. [...] Read more.
Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore, tentative high-performance liquid chromatography–diode array detection was used to analyze the polyphenol contents of leaf extracts. R. graveolens mainly contained the phenolic acids chlorogenic acid and p-coumaric acid and the flavonoids rutoside and quercetin, whereas those of A. abrotanum mainly contained the phenolic acids isochlorogenic acid and rosmarinic acid and the flavonoid quercetin. Leaf extracts of both species showed antioxidant activities due to the presence of quercetin, chlorogenic acid, and p-coumaric acid as well as antiproliferative and cytotoxic activities against cancer cells, which may be attributed to necrotic cell accumulation during the early and late apoptotic periods. Both species also exhibited antibacterial activity, although the activity was higher in R. graveolens due to the high contents of quercetin and other polyphenols. Finally, both species exhibited antifungal activities, which were associated with specific polyphenols. This is the first study to confirm the richness of polyphenols and wide spectrum of biological activities in natural populations of R. graveolens and A. abrotanum in northern Saudi Arabia. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Antioxidant Activity and Sensory Improvement of Angelica dahurica cv. Yubaizhi Essential Oil on Sunflower Oil during High-temperature Storage
Processes 2020, 8(4), 403; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8040403 - 30 Mar 2020
Cited by 4 | Viewed by 929
Abstract
The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at [...] Read more.
The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at 65 °C, ADEO (800 ppm) was able to markedly inhibit the development of the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), thiobarbituric acid reactive substances (TBARS), total polar compounds (TPC), and the absorbance at 232 and 268 nm (p < 0.01 or p < 0.05) of sunflower oil and to prominently inhibit the transformation between unsaturated fatty acids (UFA) and saturated fatty acids (SFA). Interestingly, the synergistic effect of ADEO (400 ppm) and tert-butyl hydroquinone (TBHQ, 100 ppm) was demonstrated. Furthermore, the sensory attributes such as flavor, taste, and overall acceptability of oxidized sunflower oil added by ADEO at 200, 400, and 800 ppm were memorably elevated (p < 0.05). Besides, one of its main compounds, myrcene, was demonstrated to be its active compound during the whole investigation. Consequently, TBHQ at 200 ppm could be substituted by ADEO at 800 ppm and myrcene at 69.8 ppm in the high-temperature storage at 65 °C of sunflower oil. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Low-Molecular-Weight Phenols Recovery by Eco-Friendly Extraction from Quercus Spp. Wastes: An Analytical and Biomass-Sustainability Evaluation
Processes 2020, 8(4), 387; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8040387 - 26 Mar 2020
Cited by 5 | Viewed by 959
Abstract
In this work, chemical–physical protocols aimed at the implementation of eco-friendly and biomass-sustainable recovery processes of useful compounds from forestry and/or wood industry wastes were evaluated. Four species of interest in industrial and environmental fields (Quercus cerris, Quercus ilex, and [...] Read more.
In this work, chemical–physical protocols aimed at the implementation of eco-friendly and biomass-sustainable recovery processes of useful compounds from forestry and/or wood industry wastes were evaluated. Four species of interest in industrial and environmental fields (Quercus cerris, Quercus ilex, and Robinia pseudoacacia from Central Italy, Quercus petraea from France) were submitted to neutral extraction and analyzed by gaschromatography, with mass spectrometry identification of low-molecular-weight phenols. Moreover, Quercus petraea heartwood samples were submitted to three extraction/hydrolysis protocols in an alkaline environment, and the byproducts from the lignin degradation were identified and evaluated. The recovery of bioactive phenols from forestry wastes by applying eco-friendly extractive protocols may reveal a precious strategy for rethinking the management of such wastes, in line with the fundamentals of “circular economy”. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Optimizing the Extraction of Polysaccharides from Bletilla ochracea Schltr. Using Response Surface Methodology (RSM) and Evaluating their Antioxidant Activity
Processes 2020, 8(3), 341; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8030341 - 16 Mar 2020
Cited by 4 | Viewed by 1029
Abstract
Bletilla ochracea Schltr. polysaccharides (BOP) have a similar structure to Bletilla striata (Thunb.) Reichb.f. (Orchidaceae) polysaccharides (BSP). Therefore, BOP can be considered as a substitute for BSP in the food, pharmaceuticals and cosmetics fields. To the best of our knowledge, little information is [...] Read more.
Bletilla ochracea Schltr. polysaccharides (BOP) have a similar structure to Bletilla striata (Thunb.) Reichb.f. (Orchidaceae) polysaccharides (BSP). Therefore, BOP can be considered as a substitute for BSP in the food, pharmaceuticals and cosmetics fields. To the best of our knowledge, little information is available regarding the optimization of extraction and antioxidant activity of BOP. In this study, response surface methodology (RSM) was firstly used for optimizing the extraction parameters of BOP. The results suggested that the optimal conditions included a temperature of 82 °C, a duration of 85 min and a liquid/material ratio of 30 mL/g. In these conditions, we received 26.45% ± 0.18% as the experimental yield. In addition, BOP exhibited strong concentration-dependent antioxidant abilities in vitro. The half-maximal effective concentration (EC50) values of BOP against 1,1-diphenyl-2-picrylhydrazyl (DPPH·), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonate) (ABTS+·), hydroxyl (·OH) and superoxide anion (·O2) radicals and ferrous ions (Fe2+) were determined as 692.16, 224.09, 542.22, 600.53 and 515.70 µg/mL, respectively. In conclusion, our results indicate that BOP can be a potential natural antioxidant, deserving further investigation. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Anti-Melanogenesis, Antioxidant and Anti-Tyrosinase Activities of Scabiosa columbaria L.
Processes 2020, 8(2), 236; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8020236 - 19 Feb 2020
Cited by 5 | Viewed by 1231
Abstract
Scabiosa columbaria is a plant traditionally used to treat skin ailments, such as scabies, wound bruises, sores and hyperpigmentation. To find a novel skin depigmenting agent, the present study was investigated to determine the possible anti-melanogenesis, antioxidant and anti-tyrosinase effects of methanol extract [...] Read more.
Scabiosa columbaria is a plant traditionally used to treat skin ailments, such as scabies, wound bruises, sores and hyperpigmentation. To find a novel skin depigmenting agent, the present study was investigated to determine the possible anti-melanogenesis, antioxidant and anti-tyrosinase effects of methanol extract of S. columbaria leaves. Cytotoxicity towards human dermal fibroblast (MRHF) cells was assessed using the live-cell fluorescence imaging microscopy. The inhibitory effects of the extract on tyrosinase, collagenase and melanin synthesis were also investigated using standard in vitro method, while ferric reducing power (FRAP) was used to determine the antioxidant potential of the plant extract. The effect of the extract on collagen content in MRHF cells was also investigated. The plant extract displayed no meaningful cytotoxicity towards MRHF cells and no significant cell death was recorded at all the tested concentrations. The extract (25–100 µg/mL) effectively decreased melanin content in B16F10 (mouse melanoma) cells with moderate inhibition of tyrosinase enzyme in a dose-dependent manner. However, the extract also demonstrated no significant effect on collagenase and collagen content in MRHF cells, but showed strong antioxidant activity at the concentrations tested. The results suggest that S. columbaria could be a promising candidate in the treatment of skin hyperpigmentation disorders Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Article
Antiproliferative, Antimicrobial, and Antifungal Activities of Polyphenol Extracts from Ferocactus Species
Processes 2020, 8(2), 138; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8020138 - 21 Jan 2020
Cited by 9 | Viewed by 1386
Abstract
Polyphenols, obtained from natural resources, may possess important pharmacological effects. The polyphenolic profiles of the stem extracts of six Ferocactus species (sp.): F. gracilis, F. pottsii, F. herrerae, F. horridus, F. glaucescens, and F. emoryi, were measured [...] Read more.
Polyphenols, obtained from natural resources, may possess important pharmacological effects. The polyphenolic profiles of the stem extracts of six Ferocactus species (sp.): F. gracilis, F. pottsii, F. herrerae, F. horridus, F. glaucescens, and F. emoryi, were measured using high-performance liquid chromatography (HPLC) with diode-array detection (DAD). Additionally, anticancer, antibacterial, and antifungal activities were examined. Results showed the presence of high to moderate amounts of polyphenols in the extracts (phenolic acids: Protocatechuic acid, 3,4-dihydroxyphenylacetic acid, caffeic acid, and vanillic acid; flavonoids: Rutoside and quercitrin). The highest amounts of 3,4-dihydroxyphenylacetic acid were found in F. glaucescens ((132.09 mg 100 g−1 dry weight (DW)), F. pottsii (75.71 mg 100 g−1 DW), and F. emoryi (69.14 mg 100 g−1 DW) while rutoside content was highest in F. glaucescens (107.66 mg 100 g−1 DW). Maximum antiproliferative activities were observed against HeLa and Jurkat cancer cells, with F. glaucescens, F. emoryi, and F. pottsii showing the highest anticancer activity. Most bacteria were sensitive to Ferocactus sp. stem extracts. Escherichia coli and Staphylococcus aureus were the most sensitive. Excellent antifungal effects were observed against Aspergillus ochraceus and A. niger. However, Penicillium funiculosum, P. ochrochloron, and Candida albicans were relatively resistant. This is the first study reporting novel sources of polyphenols in Ferocactus sp. with anticancer and antimicrobial activities. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Review

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Review
Antioxidant Molecules from Plant Waste: Extraction Techniques and Biological Properties
Processes 2020, 8(12), 1566; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121566 - 28 Nov 2020
Cited by 3 | Viewed by 1357
Abstract
The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical [...] Read more.
The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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Review
An Overview of Natural Extracts with Antioxidant Activity for the Improvement of the Oxidative Stability and Shelf Life of Edible Oils
Processes 2020, 8(8), 956; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8080956 - 08 Aug 2020
Cited by 15 | Viewed by 1483
Abstract
Many plant materials, such as fruits and vegetables as well as herbs and spices, represent valuable sources of antioxidants. In recent years, wastes from agriculture and food industrial processes have been shown to be interesting sources for bioactive compound recovery, strongly contributing to [...] Read more.
Many plant materials, such as fruits and vegetables as well as herbs and spices, represent valuable sources of antioxidants. In recent years, wastes from agriculture and food industrial processes have been shown to be interesting sources for bioactive compound recovery, strongly contributing to the circular economy. Nowadays, because of their possible adverse effects on human health, there is a tendency to replace synthetic antioxidants with natural compounds. This review attempts to critically summarize the current evidence on plant bioactives, extracted from food or waste, added to unsaturated vegetable oils, in order to obtain high added-value products and to ameliorate their oxidative stability and shelf life. The goal of this review is to demonstrate the current status of the research on edible oils added with natural plant bioactives, highlighting new approaches in the field of health-promoting foods. Full article
(This article belongs to the Special Issue Extraction Optimization Processes of Antioxidants)
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