scholarly journals Acid Treatment Enhances the Antioxidant Activity of Enzymatically Synthesized Phenolic Polymers

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2544
Author(s):  
Maria Laura Alfieri ◽  
Federica Moccia ◽  
Gerardino D’Errico ◽  
Lucia Panzella ◽  
Marco d’Ischia ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Acid Treatment ◽  
Antioxidant Properties ◽  
Fold Increase ◽  
Enzymatic Oxidation ◽  
Antioxidant Power ◽  
Structural Modifications ◽  
Ferric Reducing Antioxidant Power ◽  
Natural Phenolic Compounds ◽  
Electron Transfer Properties

Phenolic polymers produced by enzymatic oxidation under biomimetic and eco-friendly reaction conditions are usually endowed with potent antioxidant properties. These properties, coupled with the higher biocompatibility, stability and processability compared to low-molecular weight phenolic compounds, open important perspectives for various applications. Herein, we report the marked boosting effect of acid treatment on the antioxidant properties of a series of polymers obtained by peroxidase-catalyzed oxidation of natural phenolic compounds. Both 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated a remarkable increase in the antioxidant properties for most phenolic polymers further to the acid treatment. In particular, up to a ca. 60% decrease in the EC50 value in the DPPH assay and a 5-fold increase in the Trolox equivalents were observed. Nitric oxide- and superoxide-scavenging assays also indicated highly specific boosting effects of the acid treatment. Spectroscopic evidence suggested, in most cases, that the occurrence of structural modifications induced by the acid treatment led to more extended π-electron-conjugated species endowed with more efficient electron transfer properties. These results open new perspectives toward the design of new bioinspired antioxidants for application in food, biomedicine and material sciences.

scholarly journals Hydrolyzable vs. Condensed Wood Tannins for Bio-based Antioxidant Coatings: Superior Properties of Quebracho Tannins

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 804
Author(s):  
Federica Moccia ◽  
Alessandra Piscitelli ◽  
Samuele Giovando ◽  
Paola Giardina ◽  
Lucia Panzella ◽  
...  
Keyword(s):  
Condensed Tannins ◽  
Antioxidant Properties ◽  
Dip Coating ◽  
Enzymatic Oxidation ◽  
Functional Coatings ◽  
Nylon Membrane ◽  
Antioxidant Power ◽  
Coating Efficiency ◽  
Ferric Reducing Antioxidant Power ◽  
The Subject

Tannins have always been the subject of great interest for their countless properties, first of all their ability to produce functional coatings on a variety of materials. We report herein a comparative evaluation of the antioxidant properties of wood tannin-based coated substrates. In particular, nylon membrane filters were functionalized with chestnut (hydrolyzable) or quebracho (condensed) tannins by dip coating under different conditions. The efficiency of functionalization was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays, which invariably highlighted the superior ability of condensed tannins to induce the formation of a functional and robust coating. The results of the antioxidant assays revealed also the deleterious effects of aerial or enzymatic oxidation conditions on substrate functionalization, being more significant in the case of hydrolyzable tannins. On the other hand, the use of oxidizing conditions allowed to obtain more stable coatings, still exhibiting good antioxidant properties, in the case of condensed tannins. The presence of iron ions did not lead to a significant improvement of the coating efficiency for either tannins. The systematic approach used in this work provides novel and useful information for the optimal exploitation of tannins in antioxidant functional coatings.

scholarly journals Antioxidant Properties of Agri-Food Byproducts and Specific Boosting Effects of Hydrolytic Treatments

Antioxidants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 438 ◽  
Author(s):  
Federica Moccia ◽  
Sarai Agustin-Salazar ◽  
Luisella Verotta ◽  
Enrico Caneva ◽  
Samuele Giovando ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Condensed Tannin ◽  
Antioxidant Properties ◽  
Reducing Power ◽  
Functional Materials ◽  
Grape Pomace ◽  
Chemical Degradation ◽  
Active Components ◽  
Antioxidant Power ◽  
Structural Modifications

Largely produced agri-food byproducts represent a sustainable and easily available source of phenolic compounds, such as lignins and tannins, endowed with potent antioxidant properties. We report herein the characterization of the antioxidant properties of nine plant-derived byproducts. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) assays indicated the superior activity of pomegranate peels and seeds, grape pomace and pecan nut shell. An increase in the antioxidant potency was observed for most of the waste materials following a hydrolytic treatment, with the exception of the condensed tannin-rich pecan nut shell and grape pomace. UV-Vis and HPLC investigation of the soluble fractions coupled with the results from IR analysis and chemical degradation approaches on the whole materials allowed to conclude that the improvement of the antioxidant properties was due not only to removal of non-active components (mainly carbohydrates), but also to structural modifications of the phenolic compounds. Parallel experiments run on natural and bioinspired model phenolic polymers suggested that these structural modifications positively impacted on the antioxidant properties of lignins and hydrolyzable tannins, whereas significant degradation of condensed tannin moieties occurred, likely responsible for the lowering of the reducing power observed for grape pomace and pecan nut shell. These results open new perspectives toward the exploitation and manipulation of agri-food byproducts for application as antioxidant additives in functional materials.

scholarly journals Comparative Evaluation of Chemical Composition, Phenolic Compounds, and Antioxidant and Antimicrobial Activities of Tropical Black Bolete Mushroom Using Different Preservation Methods

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 781
Author(s):  
Jaturong Kumla ◽  
Nakarin Suwannarach ◽  
Keerati Tanruean ◽  
Saisamorn Lumyong
Keyword(s):  
Chemical Composition ◽  
Phenolic Compounds ◽  
Natural Antioxidants ◽  
Antimicrobial Activities ◽  
Fresh Sample ◽  
Antioxidant Power ◽  
Preservation Methods ◽  
Ferric Reducing Antioxidant Power ◽  
Nutritional Benefits ◽  
Antioxidant And Antimicrobial Activities

Tropical black bolete, Phlebopus portentosus, provides various nutritional benefits and natural antioxidants to humans. In this study, the chemical composition, phenolic compounds, and antioxidant and antimicrobial activities of fresh mushroom samples and samples stored for a period of one year using different preservation methods (drying, brining, and frozen) were investigated. The results indicated that the brining method significantly reduced the protein and fat contents of the mushrooms. The polyphenol and flavonoid contents of the frozen sample were not significantly different from that of the fresh sample. The results revealed that an inhibition value of 50% (IC50) for the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay of the extract of the dried and frozen samples was not statistically different from that of the fresh sample. The IC50 value of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay and ferric reducing antioxidant power (FRAP) value in the extract of the frozen sample were not found to be significantly different from those of the fresh sample. Furthermore, the lowest degree of antioxidant activity was found in the extract of the brined sample. Additionally, the antimicrobial activities of the extracts of the fresh and frozen samples were not significantly different and both extracts could have inhibited the growth of all tested Gram-positive bacteria and Pseudomonas aeruginosa.

scholarly journals Antioxidant Capacity and Phenolic and Sugar Profiles of Date Fruits Extracts from Six Different Algerian Cultivars as Influenced by Ripening Stages and Extraction Systems

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 503
Author(s):  
Malika Tassoult ◽  
Djamel Edine Kati ◽  
María África Fernández-Prior ◽  
Alejandra Bermúdez-Oria ◽  
Juan Fernandez-Bolanos ◽  
...  
Keyword(s):  
Sugar Content ◽  
Antioxidant Properties ◽  
Dry Weight ◽  
Natural Antioxidants ◽  
Antioxidant Power ◽  
Fruit Extracts ◽  
Ripening Stages ◽  
Date Fruit ◽  
Ferric Reducing Antioxidant Power ◽  
First Time

The study investigated the phenols, sugar and the antioxidant capacities of date fruit extracts obtained by organic solvents and by hydrothermal treatment from six different Algerian cultivars at two ripening stages for the first time. The analyzed cultivars exhibited potent antioxidant properties (ferric reducing antioxidant power (FRAP), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacities) and different phenols regardless of the solvents and the maturity stages. About 18 phenols were identified and quantified, mainly in the hydrothermal extracts. The earlier stages were characterized by high amounts of o-coumaric acid, cinnamic acid and luteolin, with a noticeable absence of quercetin. The tamr stage presented the highest sugar content (78.15–86.85 mg/100 mg dry weight (DW)) with an abundance of glucose. Galactose was present only in some cultivars from the kimri stage (tamjouhert). Uronic acids were mostly detected at the tamr stage (4.02–8.82 mg gallic acid equivalent/100 mg dried weight). The obtained results highlight the potential of using date fruit extracts as natural antioxidants, especially at industrial scales that tend use hydrothermal extraction.

scholarly journals Synthesis and antioxidant properties of 2-(3-(hydroxyimino)methyl)-1H-indol-1-yl)acetamide derivatives

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Chandravadivelu Gopi ◽  
Magharla Dasaratha Dhanaraju
Keyword(s):  
Antioxidant Activity ◽  
Condensation Reaction ◽  
Antioxidant Properties ◽  
Side Chain ◽  
Antioxidant Power ◽  
H Nmr ◽  
Antioxidant Agents ◽  
Phenyl Rings ◽  
Ferric Reducing Antioxidant Power ◽  
Ft Ir

Abstract Background The main aim of this work was to synthesise a novel N-(substituted phenyl)-2-(3-(hydroxyimino) methyl)-1H-indol-1-yl) acetamide derivatives and evaluate their antioxidant activity. These compounds were prepared by a condensation reaction between 1H-indole carbaldehyde oxime and 2-chloro acetamide derivatives. The newly synthesised compound structures were characterised by FT-IR, 1H-NMR, mass spectroscopy and elemental analysis. Furthermore, the above-mentioned compounds were screened for antioxidant activity by using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Result The antioxidant activity result reveals that most of the compounds were exhibiting considerable activity in both methods and the values are very closer to the standards. Among the synthesised compounds, compound 3j, 3a and 3k were shown remarkable activity at low concentration. Conclusion Compounds 3j, 3a and 3k were shown highest activity among the prepared analogues due to the attachment of halogens connected at the appropriate place in the phenyl ring. Hence, these substituted phenyl rings considered as a perfect side chain for the indole nucleus for the development of the new antioxidant agents.

scholarly journals Effect of Parinari curatellifolia Peel Flour on the Nutritional, Physical and Antioxidant Properties of Biscuits

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1262
Author(s):  
Shonisani Eugenia Ramashia ◽  
Felicia Matshepho Mamadisa ◽  
Mpho Edward Mashau
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Properties ◽  
Polyphenolic Compounds ◽  
Total Phenolic ◽  
Crude Fibre ◽  
Yellowness Index ◽  
Antioxidant Power ◽  
Parinari Curatellifolia ◽  
Ferric Reducing Antioxidant Power ◽  
The Impact

This study investigated the impact of Parinari curatellifolia peel flour on the nutritional, physical and antioxidant properties of formulated biscuits. Biscuits enriched with 5%, 10%, 15% and 20% of Parinari (P). curatellifolia peel flour were formulated and characterised. Thermal, physicochemical, polyphenolic compounds and antioxidant properties of flour and biscuits were determined. The incorporation of P. curatellifolia peel flour significantly increased (p < 0.05) thermal properties (onset, peak and conclusion temperatures) of flour. However, enthalpy of gelatinisation, viscosity and pH of flour samples decreased. Nutritional analysis revealed an increase in ash (0.74% to 2.23%) and crude fibre contents (0.39% to 2.95%) along with an increase of P. curatellifolia peel flour levels. Protein content and carbohydrates decreased while moisture content was insignificantly affected by the addition of P. curatellifolia peel flour. The L*, b* values and whiteness index of formulated biscuits decreased while parameter a* value (10.76 to 21.89) and yellowness index (69.84 to 102.71) decreased. Physical properties such as diameter (3.57 mm to 3.97 mm), spread ratio (2.67 to 3.45) and hardness (1188.13 g to 2432.60 g) increased with the inclusion levels of peel flour while weight and thickness decreased. The inclusion of P. curatellifolia improved the polyphenolic compounds and antioxidant activity of biscuits with values of total flavonoids content ranging from 0.028 to 0.104 mg CE/g, total phenolic content increasing from 20.01 mg to 48.51 mg GAE/g, ferric reducing antioxidant power (FRAP) increasing from 108.33 mg to 162.67 mg GAE/g and DPPH (2,2-diphenyl-1-picrylhydrazyl) from 48.70% to 94.72%. These results lead to the recommendation of the utilisation of P. curatellifolia peel flour to enhance the nutritional value, polyphenolic compounds and antioxidant activity of bakery products such as biscuits.

scholarly journals Comparative Evaluation of Argania spinosa and Olea europaea Leaf Phenolic Compounds and their Antioxidant Activity

Botanica ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 76-87
Author(s):  
Aziza Lfitat ◽  
Hind Zejli ◽  
Abdelkamel Bousselham ◽  
Yassine El Atki ◽  
Badiaa Lyoussi ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Total Phenolic ◽  
Olive Leaves ◽  
Antioxidant Power ◽  
Ferric Reducing Antioxidant Power ◽  
Total Flavonoids Content

AbstractWe conducted this study to determine and compare the content of phenolic compounds and flavonoids in the argan and olive leaves as well as their antioxidant capacity in aqueous, methanolic, and ethyl acetate extracted fractions. In vitro antioxidant activity was evaluated in comparison with synthetic antioxidants by assessing DPPH• radical scavenging capacity, ferric reducing antioxidant power, scavenging ability by inhibiting the β-carotene/linoleic acid emulsion oxidation, and by the ABTS radical scavenging activity assay. Total phenolic content in argan samples ranged from 221.69 ± 2.07 to 1.32 ± 0.01 mg GAE/g DW and in olive samples from 144.61 ± 0.82 to 1.21 ± 0.02 mg GAE/g DW. Total flavonoids content in argan samples varied from 267.37 ± 1.12 to 25.48 ± 0.02 mg QE/g DW, while in olives from 96.06 ± 0.78 to 10.63 ± 0.05 mg QE/g DW. In vitro antioxidant studies strongly confirmed the antioxidant potency of argan and olive leaves and their richness in secondary metabolites that are effective in free radicals scavenging and metal chelating capacities, indicating their antioxidant power.

scholarly journals UPLC-QTOF-MS/MS and GC-MS Characterization of Phytochemicals in Vegetable Juice Fermented Using Lactic Acid Bacteria from Kimchi and Their Antioxidant Potential

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1761
Author(s):  
Moeun Lee ◽  
Jung Hee Song ◽  
Eun Ji Choi ◽  
Ye-Rang Yun ◽  
Ki Won Lee ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Phenyllactic Acid ◽  
Antioxidant Power ◽  
Vegetable Juice ◽  
Daucus Carota L ◽  
Ferric Reducing Antioxidant Power

This study aims to investigate fermentative metabolites in probiotic vegetable juice from four crop varieties (Brassica oleracea var. capitata, B. oleracea var. italica, Daucus carota L., and Beta vulgaris) and their antioxidant properties. Vegetable juice was inoculated with two lactic acid bacteria (LAB) (Companilactobacillus allii WiKim39 and Lactococcus lactis WiKim0124) isolated from kimchi and their properties were evaluated using untargeted UPLC-QTOF-MS/MS and GC-MS. The samples were also evaluated for radical (DPPH• and OH•) scavenging activities, lipid peroxidation, and ferric-reducing antioxidant power. The fermented vegetable juices exhibited high antioxidant activities and increased amounts of total phenolic compounds. Fifteen compounds and thirty-two volatiles were identified using UPLC-QTOF-MS/MS and GC-MS, respectively. LAB fermentation significantly increased the contents of d-leucic acid, indole-3-lactic acid, 3-phenyllactic acid, pyroglutamic acid, γ-aminobutyric acid, and gluconic acid. These six metabolites showed a positive correlation with antioxidant properties. Thus, vegetable juices fermented with WiKim39 and WiKim0124 can be considered as novel bioactive health-promoting sources.

scholarly journals Antioxidant Activities and Volatile Flavor Components of Selected Single-Origin and Blend Chocolates

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3648
Author(s):  
Lucia Godočiková ◽  
Eva Ivanišová ◽  
Grzegorz Zaguła ◽  
Luis Noguera-Artiaga ◽  
Ángel A. Carbonell-Barrachina ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Acids ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Total Content ◽  
Composition Analysis ◽  
High Positive Correlation ◽  
Antioxidant Power ◽  
Single Origin ◽  
Ferric Reducing Antioxidant Power

The biological activity of chocolates gains more and more attention of consumers. Its antioxidant properties depend, among other factors, mainly on the origin of cocoa and the characteristics that this origin gives to the final product. Therefore, the aim of the study was to measure and compare the total content of polyphenols, antioxidant activity, and key odorants of commercial chocolates made from blend cocoa with single-origin ones. The highest content of polyphenols was found in 90% blend cocoa chocolate and single-origin samples, while the lowest content was exhibited by 100% chocolate from blend cocoa mass. The highest antioxidant activity measured by 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and ferric reducing antioxidant power (FRAP) assays was observed in the sample of chocolate with 90% cocoa solids from blend mass, followed by single-origin chocolates. A high positive correlation between ABTS assay and the total polyphenol and phenolic acids’ content, as well as among the total content of polyphenols, flavonoids, and phenolic acids was found. Mineral composition analysis showed that dark chocolate is a valuable source of some elements, especially Mg, Fe, and Zn. Potentially toxic elements were not detected or below permitted limits. Moreover, it was noticed that the main volatile compound in all tested samples was acetic acid, but pyrazines were considered the most important group of chocolate odorants.

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