Antioxidants in Oils

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Natural and Synthetic Antioxidants".

Deadline for manuscript submissions: closed (30 December 2013) | Viewed by 153091

Special Issue Editor

Department of Food and Nutritional Sciences, University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK
Interests: antioxidants in food; antioxidant mechanisms; food chemistry; phytochemicals; bioavailability of antioxidants
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues:

Edible oils contain a range of natural antioxidants. Vitamin E is the most widespread and widely studied, although oils contain mixtures of tocopherols and tocotrienols that vary in their contribution to the stability of oils and also vary in their significance for human nutrition. Some oils contain very characteristic antioxidants including virgin olive oil that contains mixtures of secoiridoids, and sesame oil, which contains mixtures of lignans with antioxidant properties.

It is widely recognised that the matrix of the food or biological system affects the activity of antioxidants, and much work is needed to clarify the interactions of antioxidants with proteins and other components, and the significance of antioxidants for human health. This issue will allow publication of all aspects of the properties of antioxidants in oils, and their significance for oil stability and health.

Prof. Dr. Michael H. Gordon
Guest Editor

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Keywords

  • antioxidant
  • edible oil
  • phenolic compounds
  • oxidation
  • lipids
  • stability
  • nutrition
  • bioavailability

Published Papers (15 papers)

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799 KiB  
Article
Endogenous Phenolics in Hulls and Cotyledons of Mustard and Canola: A Comparative Study on Its Sinapates and Antioxidant Capacity
by Shyamchand Mayengbam, Ayyappan Aachary and Usha Thiyam-Holländer
Antioxidants 2014, 3(3), 544-558; https://doi.org/10.3390/antiox3030544 - 15 Aug 2014
Cited by 24 | Viewed by 6556
Abstract
Endogenous sinapic acid (SA), sinapine (SP), sinapoyl glucose (SG) and canolol (CAN) of canola and mustard seeds are the potent antioxidants in various lipid-containing systems. The study investigated these phenolic antioxidants using different fractions of canola and mustard seeds. Phenolic compounds were extracted [...] Read more.
Endogenous sinapic acid (SA), sinapine (SP), sinapoyl glucose (SG) and canolol (CAN) of canola and mustard seeds are the potent antioxidants in various lipid-containing systems. The study investigated these phenolic antioxidants using different fractions of canola and mustard seeds. Phenolic compounds were extracted from whole seeds and their fractions: hulls and cotyledons, using 70% methanol by the ultrasonication method and quantified using HPLC-DAD. The major phenolics from both hulls and cotyledons extracts were SP, with small amounts of SG, and SA with a significant difference of phenolic contents between the two seed fractions. Cotyledons showed relatively high content of SP, SA, SG and total phenolics in comparison to hulls (p < 0.001). The concentration of SP in different fractions ranged from 1.15 ± 0.07 to 12.20 ± 1.16 mg/g and followed a decreasing trend- canola cotyledons > mustard cotyledons > mustard seeds > canola seeds > mustard hulls > canola hulls. UPLC-tandem Mass Spectrometry confirmed the presence of sinapates and its fragmentation in these extracts. Further, a high degree of correlation (r = 0.93) was noted between DPPH scavenging activity and total phenolic content. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Article
Screening of Antioxidant Activity of Gentian Lutea Root and Its Application in Oil-in-Water Emulsions
by Nurul Aini Mohd Azman, Francisco Segovia, Xavier Martínez-Farré, Emilio Gil and María Pilar Almajano
Antioxidants 2014, 3(2), 455-471; https://doi.org/10.3390/antiox3020455 - 19 Jun 2014
Cited by 32 | Viewed by 8389
Abstract
Gentiana Lutea root (G. Lutea) is a medicinal herb, traditionally used as a bitter tonic in gastrointestinal ailments for improving the digestive system. The active principles of G. Lutea were found to be secoiridoid bitter compounds as well as [...] Read more.
Gentiana Lutea root (G. Lutea) is a medicinal herb, traditionally used as a bitter tonic in gastrointestinal ailments for improving the digestive system. The active principles of G. Lutea were found to be secoiridoid bitter compounds as well as many other active compounds causing the pharmacological effects. No study to date has yet determined the potential of G. Lutea antioxidant activity on lipid oxidation. Thus, the aim of this study was to evaluate the effects of an extract of G. Lutea on lipid oxidation during storage of an emulsion. G. Lutea extracts showed excellent antioxidant activity measured by DPPH scavenging assay and Trolox equivalent antioxidant capacity (TEAC) assays. An amount of 0.5% w/w G. Lutea lyophilise was able to inhibit lipid oxidation throughout storage (p < 0.05). A mixture of G. Lutea with 0.1% (w/w) BSA showed a good synergic effect and better antioxidant activity in the emulsion. Quantitative results of HPLC showed that G. Lutea contained secoiridoid-glycosides (gentiopiocroside and sweroside) and post column analysis displayed radical scavenging activity of G. Lutea extract towards the ABTS radical. The results from this study highlight the potential of G. Lutea as a food ingredient in the design of healthier food commodities. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Article
Avocado Seeds: Extraction Optimization and Possible Use as Antioxidant in Food
by Francisco Segovia Gómez, Sara Peiró Sánchez, Maria Gabriela Gallego Iradi, Nurul Aini Mohd Azman and María Pilar Almajano
Antioxidants 2014, 3(2), 439-454; https://doi.org/10.3390/antiox3020439 - 10 Jun 2014
Cited by 64 | Viewed by 17313
Abstract
Consumption of avocado (Persea americana Mill) has increased worldwide in recent years. Part of this food (skin and seed) is lost during processing. However, a high proportion of bioactive substances, such as polyphenols, remain in this residue. The primary objective of this [...] Read more.
Consumption of avocado (Persea americana Mill) has increased worldwide in recent years. Part of this food (skin and seed) is lost during processing. However, a high proportion of bioactive substances, such as polyphenols, remain in this residue. The primary objective of this study was to model the extraction of polyphenols from the avocado pits. In addition, a further objective was to use the extract obtained to evaluate the protective power against oxidation in food systems, as for instance oil in water emulsions and meat products. Moreover, the possible synergy between the extracts and egg albumin in the emulsions is discussed. In Response Surface Method (RSM), the variables used are: temperature, time and ethanol concentration. The results are the total polyphenols content (TPC) and the antiradical power measured by Oxygen Radical Antioxidant Capacity (ORAC). In emulsions, the primary oxidation, by Peroxide Value and in fat meat the secondary oxidation, by TBARS (Thiobarbituric acid reactive substances), were analyzed. The RSM model has an R2 of 94.69 for TPC and 96.7 for ORAC. In emulsions, the inhibition of the oxidation is about 30% for pure extracts and 60% for the combination of extracts with egg albumin. In the meat burger oxidation, the formation of TBARS is avoided by 90%. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Article
The Effectiveness of Rambutan (Nephelium lappaceum L.) Extract in Stabilization of Sunflower Oil under Accelerated Conditions
by Winne Sia Chiaw Mei, Amin Ismail, Norhaizan Mohd. Esa, Gabriel Akyirem Akowuah, Ho Chun Wai and Yim Hip Seng
Antioxidants 2014, 3(2), 371-386; https://doi.org/10.3390/antiox3020371 - 09 May 2014
Cited by 42 | Viewed by 12114
Abstract
The oxidative properties of sunflower oil supplemented with rambutan extract, (crude extract and its fractionated fraction, SF II) in comparison with synthetic antioxidant were investigated. The supplemented sunflower oils were stored under accelerated conditions for 24 days at 60 °C. For every 6-day [...] Read more.
The oxidative properties of sunflower oil supplemented with rambutan extract, (crude extract and its fractionated fraction, SF II) in comparison with synthetic antioxidant were investigated. The supplemented sunflower oils were stored under accelerated conditions for 24 days at 60 °C. For every 6-day interval, the oxidative properties of the supplemented sunflower oil were evaluated based on the following tests, namely peroxide value, p-anisidine value, Thiobarbituric Acid Reactive Substances (TBARS) assay, iodine value and free fatty acids. The total oxidation (TOTOX) values were also calculated based on the peroxide values and p-anisidine values. Rambutan extract is a potential source of antioxidant. The oxidative activities of the extracts at all concentrations were significantly (p < 0.05) higher than the control. Generally, the partially fractionated fraction was more effective than the crude extract. With a 2-year storage period at ambient temperature, the fractionated fraction of the extract, SF II at 300 ppm, was observed to work more effectively than the synthetic antioxidant, t-Tocopherol, and it possessed a protective effect comparable with butylatedhydrioxynanisole (BHA). Therefore, rambutan extract could be used as a potential alternative source of antioxidant in the oil industry or other fat-based products to delay lipid oxidation. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Article
Extraction of Antioxidants from Borage (Borago officinalis L.) Leaves—Optimization by Response Surface Method and Application in Oil-in-Water Emulsions
by Francisco Segovia, Bryshila Lupo, Sara Peiró, Michael H. Gordon and María Pilar Almajano
Antioxidants 2014, 3(2), 339-357; https://doi.org/10.3390/antiox3020339 - 06 May 2014
Cited by 19 | Viewed by 8361
Abstract
Borage (Borago officinalis L.) is a typical Spanish plant. During processing, 60% are leaves. The aim of this work is to model and optimize the extraction of polyphenol from borage leaves using the response surface method (RSM) and to use this extract [...] Read more.
Borage (Borago officinalis L.) is a typical Spanish plant. During processing, 60% are leaves. The aim of this work is to model and optimize the extraction of polyphenol from borage leaves using the response surface method (RSM) and to use this extract for application in emulsions. The responses were: total polyphenol content (TPC), antioxidant capacity by ORAC, and rosmarinic acid by HPLC. The ranges of the variables temperature, ethanol content and time were 50–90 °C, 0%–30%–60% ethanol (v/v), and 10–15 min. For ethanolic extraction, optimal conditions were at 75.9 °C, 52% ethanol and 14.8 min, yielding activity of 27.05 mg GAE/g DW TPC; 115.96 mg TE/g DW in ORAC and 11.02 mg/L rosmarinic acid. For water extraction, optimal activity was achieved with extraction at 98.3 °C and 22 min, with responses of 22.3 mg GAE/g DW TPC; 81.6 mg TE/g DW in ORAC and 3.9 mg/L rosmarinic acid. The significant variables were ethanol concentration and temperature. For emulsions, the peroxide value was inhibited by 60% for 3% extract concentration; and 80% with 3% extract concentration and 0.2% of BSA. The p-anisidine value between the control and the emulsion with 3% extract was reduced to 73.6% and with BSA 86.3%, and others concentrations had similar behavior. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Article
Distribution and Antioxidant Efficiency of Resveratrol in Stripped Corn Oil Emulsions
by Sonia Losada-Barreiro, Marlene Costa, Carlos Bravo-Díaz and Fátima Paiva-Martins
Antioxidants 2014, 3(2), 212-228; https://doi.org/10.3390/antiox3020212 - 04 Apr 2014
Cited by 48 | Viewed by 8672
Abstract
We investigated the effects of resveratrol (RES) on the oxidative stability of emulsions composed of stripped corn oil, acidic water and Tween 20 and determined its distribution in the intact emulsions by employing a well-established kinetic method. The distribution of RES is described [...] Read more.
We investigated the effects of resveratrol (RES) on the oxidative stability of emulsions composed of stripped corn oil, acidic water and Tween 20 and determined its distribution in the intact emulsions by employing a well-established kinetic method. The distribution of RES is described by two partition constants, that between the oil-interfacial region, POI, and that between the aqueous and interfacial region, PWI. The partition constants, POI and PWI, are obtained in the intact emulsions from the variations of the observed rate constant, kobs, for the reaction between the hydrophobic 4-hexadecylbenzenediazonium ion and RES with the emulsifier volume fraction, ФI. The obtained POI and PWI values are quite high, PWI = 4374 and POI = 930, indicating that RES is primarily located in the interfacial region of the emulsions, %RESI > 90% at ФI = 0.005, increasing up to 99% at ФI = 0.04. The oxidative stability of the corn oil emulsions was determined by measuring the formation of conjugated dienes at a given time in the absence and in the presence of RES. The addition of RES did not improve their oxidative stability in spite that more than 90% of RES is located in the interfacial region of the emulsion, because of the very low radical scavenging activity of RES. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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189 KiB  
Article
Effect of Drying Operating Conditions on Canola Oil Tocopherol Content
by Daniela Laoretani, María Fernández, Guillermo Crapiste and Susana Nolasco
Antioxidants 2014, 3(2), 190-199; https://doi.org/10.3390/antiox3020190 - 27 Mar 2014
Cited by 20 | Viewed by 5916
Abstract
The aim of this work was to evaluate two operating parameters of seed drying (temperature and initial moisture content) on the tocopherol content of canola oil. The raw material was characterized by moisture, oil, protein, crude fiber and ash content. Seeds at 13.6% [...] Read more.
The aim of this work was to evaluate two operating parameters of seed drying (temperature and initial moisture content) on the tocopherol content of canola oil. The raw material was characterized by moisture, oil, protein, crude fiber and ash content. Seeds at 13.6% and 22.7% moisture content (dry basis, db) were dried at temperatures in the range of 35–100 °C to a safe storage moisture of 7% db. Oil was extracted from each treated sample. The oil extracted from the samples dried at the extreme temperatures was analyzed by means of the acidity value, peroxide index and fatty acid composition, finding no significant differences among treatments or among untreated and treated samples. Tocopherol contents in the oils obtained for all the assayed temperatures were determined. Differences were found for the samples with 22.7% (db) initial moisture content. Except at 35 °C, temperature affected negatively the oil tocopherol content. However, when 13.6% (db) moisture seeds were processed, no significant differences were observed in the amount of this minor oil component among assays. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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307 KiB  
Article
Effectiveness of α-, γ- and δ-Tocopherol in a CLA-Rich Oil
by Gloria Márquez-Ruiz, María Del Carmen García-Martínez, Francisca Holgado and Joaquín Velasco
Antioxidants 2014, 3(1), 176-188; https://doi.org/10.3390/antiox3010176 - 17 Mar 2014
Cited by 12 | Viewed by 6210
Abstract
Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have been attributed to some isomers, such as anticarcinogenic activity, antiartherosclerotic effects and reduction of body fat gain. Hence, oils rich [...] Read more.
Conjugated linoleic acid (CLA) is a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bounds. Positive health properties have been attributed to some isomers, such as anticarcinogenic activity, antiartherosclerotic effects and reduction of body fat gain. Hence, oils rich in CLA such as Tonalin® oil (TO), normally obtained through alkaline isomerization of safflower oil (SO), an oil rich in linoleic acid (LA), are currently used in functional foods. However, special care must be taken to protect them from oxidation to ensure the quality of the supplemented foods. The objective of this work was to evaluate the oxidation and effectiveness of different tocopherol homologues (α-, γ- and δ-), alone or in combination with synergists (ascorbyl palmitate and lecithin), in TO compared to SO at different conditions, ambient temperature (25 °C) and accelerated conditions in Rancimat (100 °C). The oils, the oils devoid of their antioxidants and the latter containing the antioxidants added were assayed. Results showed great differences between SO and TO in terms of formation of hydroperoxides and polymers and also in the effectiveness of tocopherols to delay oxidation. TO showed higher levels of polymerization and, in general, the effectiveness of tocopherol homologues, alone or in combination with synergists, was also lower in the TO. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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304 KiB  
Article
Antioxidant Properties of Artemisia annua Extracts in Model Food Emulsions
by Monika Skowyra, Maria Gabriela Gallego, Francisco Segovia and Maria Pilar Almajano
Antioxidants 2014, 3(1), 116-128; https://doi.org/10.3390/antiox3010116 - 03 Mar 2014
Cited by 45 | Viewed by 8909
Abstract
Artemisia annua is currently the only commercial source of the sesquiterpene lactone artemisinin. Although artemisinin is a major bioactive component present in this Chinese herb, leaf flavonoids have shown a variety of biological activities. The polyphenolic profile of extract from leaves of A. [...] Read more.
Artemisia annua is currently the only commercial source of the sesquiterpene lactone artemisinin. Although artemisinin is a major bioactive component present in this Chinese herb, leaf flavonoids have shown a variety of biological activities. The polyphenolic profile of extract from leaves of A. annua was assessed as a source of natural antioxidants. Total phenolic content and total flavonoid content were established and three assays were used to measure the antioxidant capacity of the plant extract. The measurement of scavenging capacity against the 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation, the oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP) were 314.99 µM Trolox equivalents (TE)/g DW, 736.26 µM TE/g DW and 212.18 µM TE/g DW, respectively. A. annua extracts also showed good antioxidant properties in 10% sunflower oil-in-water emulsions during prolonged storage (45 days) at 32 °C. Artemisia extract at 2 g/L was as effective as butylated hydroxyanisole (BHA) at 0.02 g/L in slowing down the formation of hydroperoxides as measured by peroxide value and thiobarbituric acid reactive substances. The results of this study indicate that extract of A. annua may be suitable for use in the food matrix as substitutes for synthetic antioxidants. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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329 KiB  
Article
Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism
by Martina Höferl, Ivanka Stoilova, Erich Schmidt, Jürgen Wanner, Leopold Jirovetz, Dora Trifonova, Lutsian Krastev and Albert Krastanov
Antioxidants 2014, 3(1), 81-98; https://doi.org/10.3390/antiox3010081 - 24 Feb 2014
Cited by 109 | Viewed by 20562
Abstract
The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of [...] Read more.
The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and β-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН) scavenging and chelating capacity, superoxide radical (O2) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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403 KiB  
Article
Antioxidative Polyphenols from Defatted Oilseed Cakes: Effect of Solvents
by Sue-Siang Teh, Alaa El-Din Bekhit and John Birch
Antioxidants 2014, 3(1), 67-80; https://doi.org/10.3390/antiox3010067 - 24 Feb 2014
Cited by 64 | Viewed by 8812
Abstract
Defatted hemp, flax and canola seed cakes were extracted with different solvent systems namely methanol, ethanol, acetone, methanol 80%, acetone 80% and mixed solvent of methanol:acetone:water (MAW, 7:7:6, v/v/v). Each extract was analyzed for antioxidant capacity using ferric reducing/antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl [...] Read more.
Defatted hemp, flax and canola seed cakes were extracted with different solvent systems namely methanol, ethanol, acetone, methanol 80%, acetone 80% and mixed solvent of methanol:acetone:water (MAW, 7:7:6, v/v/v). Each extract was analyzed for antioxidant capacity using ferric reducing/antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. MAW exhibited the highest extraction of phenolic and flavonoid contents in the seed cakes, followed by acetone 80% and methanol 80%. The antioxidant capacity was proportional to the polyphenols recovery in the extracts. Canola seed cakes possessed the highest recovery of polyphenols and antioxidant capacity, followed by hemp and flax seed cakes. MAW extract of canola contained total phenolic content, 2104.67 ± 2.52 mg GAE/100 g fresh weight; total flavonoids, 37.79 ± 0.04 mg LUE/100 g fresh weight; percentage inhibition of DPPH, 33.03 ± 0.38%; FRAP assay, 8.78 ± 0.07 μmol Fe (II)/g fresh weight. Identification of individual polyphenol compounds were performed HPLC. MAW extract of canola had the highest (P < 0.05) concentration of all individual polyphenols except gallic acid and catechin. Highest concentration of quercetin and luteolin in MAW extract of hemp was obtained among all solvent systems. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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869 KiB  
Article
The Effect of Perilla frutescens Extract on the Oxidative Stability of Model Food Emulsions
by Monika Skowyra, Victor Falguera, Nurul A. M. Azman, Francisco Segovia and Maria P. Almajano
Antioxidants 2014, 3(1), 38-54; https://doi.org/10.3390/antiox3010038 - 22 Jan 2014
Cited by 32 | Viewed by 8560
Abstract
The polyphenolic profile of leaves and stalks of Perilla frutescens, was assessed as a source of natural antioxidants. The amount of caffeic and rosmarinic acids, determined by high-performance liquid chromatography (HPLC), were 0.51 mg/g dry weight (DW) and 2.29 mg/g DW, respectively. [...] Read more.
The polyphenolic profile of leaves and stalks of Perilla frutescens, was assessed as a source of natural antioxidants. The amount of caffeic and rosmarinic acids, determined by high-performance liquid chromatography (HPLC), were 0.51 mg/g dry weight (DW) and 2.29 mg/g DW, respectively. The measurement of scavenging capacity against the 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation, the oxygen radical absorbance capacity (ORAC), and the ferric reducing antioxidant power (FRAP) were 65.03 mg Trolox equivalents (TE)/g DW, 179.60 mg TE/g DW and 44.46 mg TE/g DW, respectively. P. frutescens extracts also showed good antioxidant properties in 10% sunflower oil-in-water emulsions during storage at 32 °C. Perilla extract at 320 ppm was as effective as butylated hydroxyanisole (BHA) at 20 ppm in slowing down the formation of hydroperoxides as measured by peroxide value, thiobarbituric acid reactive substances and hexanal content. The results of this study indicate that extract of P. frutescens may be suitable for use in the food matrix to help achieve potential health benefits. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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227 KiB  
Article
Chemical Composition and Antioxidant Activity of Essential Oils from Cinnamodendron dinisii Schwacke and Siparuna guianensis Aublet
by Milene Aparecida Andrade, Maria Das Graças Cardoso, Juliana De Andrade, Lucilene Fernandes Silva, Maria Luisa Teixeira, Juliana Maria Valério Resende, Ana Cristina Da Silva Figueiredo and José Gonçalves Barroso
Antioxidants 2013, 2(4), 384-397; https://doi.org/10.3390/antiox2040384 - 26 Nov 2013
Cited by 114 | Viewed by 10301
Abstract
The objectives of this study were to chemically characterize and evaluate the antioxidant activity of essential oils Cinnamodendron dinisii Schwacke (pepper) and Siparuna guianensis Aublet (negramina). The essential oil was isolated by hydrodistillation using a Clevenger modified apparatus, and the identification and quantification [...] Read more.
The objectives of this study were to chemically characterize and evaluate the antioxidant activity of essential oils Cinnamodendron dinisii Schwacke (pepper) and Siparuna guianensis Aublet (negramina). The essential oil was isolated by hydrodistillation using a Clevenger modified apparatus, and the identification and quantification of constituents, through GC/MS and GC-FID analysis. The antioxidant activity was evaluated using β-carotene/linoleic acid system and the DPPH radical sequestering method. In chromatographic analysis, the majority constituents found in the essential oil of C. dinisii were bicyclic monoterpenes, α-pinene (35.41%), β-pinene (17.81%), sabinene (12.01%) and sesquiterpene bicyclogermacrene (7.59%). In the essential oil of the fresh leaves of Siparuna guianensis Aublet, acyclic monoterpene, β-myrcene (13.14%), and sesquiterpenes, germacrene-D (8.68%) and bicyclogermacrene (16.71%) were identified. The antioxidant activity was low by the β-carotene/linoleic acid test and was not evidenced by the DPPH test, for both oils evaluated. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
262 KiB  
Article
Antioxidant Potential of the Extracts, Fractions and Oils Derived from Oilseeds
by Shagufta Ishtiaque, Nasir Khan, Muhammad A. Siddiqui, Rahmanullah Siddiqi and Shahina Naz
Antioxidants 2013, 2(4), 246-256; https://doi.org/10.3390/antiox2040246 - 15 Oct 2013
Cited by 30 | Viewed by 7342
Abstract
The polyphenolic extracts and oils were obtained from ajwain, mustard, fenugreek and poppy seeds. The extracts were partitioned into acidic and neutral polyphenolic fractions and following estimation of total phenolics in the crude extract, acidic and neutral fractions and oil, all were [...] Read more.
The polyphenolic extracts and oils were obtained from ajwain, mustard, fenugreek and poppy seeds. The extracts were partitioned into acidic and neutral polyphenolic fractions and following estimation of total phenolics in the crude extract, acidic and neutral fractions and oil, all were analyzed for their DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging potential, ferric reducing ability and chelating power. The highest amount of polyphenols was found in ajwain (8330 ± 107), then in mustard seeds (2844 ± 56.00) and in fenugreek (1130 ± 29.00), and least in poppy seeds (937 ± 18.52). The higher amounts of polyphenols were estimated in neutral fraction compared to acidic (p < 0.05). % Inhibition of DPPH by the crude extract and fractions of all oilseeds was quite significant, being higher for acidic than neutral. The highest % DPPH inhibition was shown by ajwain extract than mustard > fenugreek and least by poppy seed extracts (p < 0.05). The reducing power and the chelating effect of the oilseeds followed the same order as DPPH, but higher % chelation was shown by neutral than acidic fraction (p < 0.05). Though low in polyphenols, the oil fractions were as strong antioxidants as the acidic one. Though oilseeds are used in very small quantity in food, they are potential sources of natural antioxidants and may replace synthetic ones. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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Review

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297 KiB  
Review
Antioxidants in Greek Virgin Olive Oils
by Nick Kalogeropoulos and Maria Z. Tsimidou
Antioxidants 2014, 3(2), 387-413; https://doi.org/10.3390/antiox3020387 - 13 May 2014
Cited by 96 | Viewed by 10061
Abstract
Greece is ranked third after Spain and Italy in virgin olive oil production. The number of Greek olive cultivars—excluding clonal selections—is greater than 40; however, more than 90% of the acreage is cultivated with 20 cultivars, adapted to a wide range of environmental [...] Read more.
Greece is ranked third after Spain and Italy in virgin olive oil production. The number of Greek olive cultivars—excluding clonal selections—is greater than 40; however, more than 90% of the acreage is cultivated with 20 cultivars, adapted to a wide range of environmental conditions. Greek virgin olive oils, produced mainly with traditional, non-intensive cultivation practices, are mostly of exceptional quality. The benefits of consuming virgin olive oil, originally attributed to its high oleic acid content, are now considered to be the combined result of several nutrient and non-nutrient phytochemicals. The present work summarizes available data regarding natural antioxidants in Greek virgin olive oils (VOO) namely, polar phenolic compounds, tocopherols, squalene, and triterpenic acids. The literature survey indicated gaps in information, which should be filled in the near future so that the intrinsic properties of this major agricultural product of Greece will be substantiated on a solid scientific basis. Full article
(This article belongs to the Special Issue Antioxidants in Oils)
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