Special Issue "Antioxidants in Olive 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 June 2019).

Special Issue Editors

Guest Editor
Dr. Isabel Seiquer Website E-Mail
Department of Physiology and Biochemistry of Animal Nutrition, Estación Experimental del Zaidín (EEZ), Spanish National research Council (CSIC), Granada, Spain
Interests: edible oils; olive oil; antioxidant properties; food quality; dietary minerals; digestive process; bioavailability; cell cultures; antioxidant markers
Guest Editor
Dr. Jesús R. Huertas Website E-Mail
Institute of Nutrition and Food Technology “José Mataix”, Biomedical Research Centre, Department of Physiology, University of Granada, Granada, Spain
Interests: antioxidants; adaptation of antioxidant mechanisms; new physiological antioxidants in response to extreme stress; the relationship between different doses of dietary antioxidants and gene expression during physical activity; mitochondrial free radical production and cell signaling; antioxidants component of virgin olive oil; aging; oxidative stress and apoptosis; and new food antioxidants

Special Issue Information

Dear Colleagues,

Olive oil, and especially virgin olive oil (VOO), is well recognized as one of the healthiest edible oils in human diet. Multiple biological properties, providing beneficial effects in the prevention of degenerative diseases and also of aging, have been attributed to olive oil, and are mainly based on its antioxidant potential. The protective role of VOO is the results of its particular fatty acid composition (with a high content of oleic acid) and the wide number of minor constituents with antioxidant properties. Among these, polyphenols (especially hydroxytyrosol and oleuropein) and tocopherols are of major interest, but other components, such as Coenzyme Q and pigments, also contribute to the antioxidant properties of VOO. Antioxidants of VOO are of high importance, not only acting in vivo against free radicals at any level, but also for the sensory quality and shelf-life of oil. In this sense, the antioxidant properties of VOO may be affected by different factors, such as cultivar, climatic and geographic aspects of producing areas and technologic aspects of oil production.

Many in vitro, ex-vivo, and in vivo studies, using different approaches and tests, have been carried out to investigate antioxidant activity of VOO over the last few years, and the related scientific research is of great interest. Therefore, in this Special Issue, original research papers or review articles focused on the different aspects of antioxidant compounds in olive oil are welcome.

Dr. Isabel Seiquer
Dr. Jesús R. Huertas
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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. Antioxidants 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 1200 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

  • Virgin olive oil
  • Antioxidants properties
  • Antioxidant compounds
  • Polyphenols
  • Tocopherols
  • Oxidative stress
  • Health benefits

Published Papers (9 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Open AccessArticle
Hydroxytyrosol Supplementation Modifies Plasma Levels of Tissue Inhibitor of Metallopeptidase 1 in Women with Breast Cancer
Antioxidants 2019, 8(9), 393; https://doi.org/10.3390/antiox8090393 - 11 Sep 2019
Abstract
The etiology of breast cancer can be very different. Most antineoplastic drugs are not selective against tumor cells and also affect normal cells, leading to a wide variety of adverse reactions such as the production of free radicals by altering the redox state [...] Read more.
The etiology of breast cancer can be very different. Most antineoplastic drugs are not selective against tumor cells and also affect normal cells, leading to a wide variety of adverse reactions such as the production of free radicals by altering the redox state of the organisms. Therefore, the objective of this study was to elucidate if hydroxytyrosol (HT) (an antioxidant present in extra virgin olive oil) has a chemomodulatory effect when combined with the chemotherapeutic drugs epirubicin and cyclophosphamide followed by taxanes in breast cancer patients. Changes in plasma levels of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) throughout the chemotherapy treatment were studied. Both molecules are involved in cell proliferation, apoptosis, neoangiogenesis, and metastasis in breast cancer patients. Women with breast cancer were divided into two groups: a group of patients receiving a dietary supplement of HT and a control group of patients receiving placebo. The results showed that the plasma levels of TIMP-1 in the group of patients receiving HT were significantly lower than those levels found in the control group after the epirubicin-cyclophosphamide chemotherapy. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Figure 1

Open AccessArticle
An Aromatic Aldehyde Synthase Controls the Synthesis of Hydroxytyrosol Derivatives Present in Virgin Olive Oil
Antioxidants 2019, 8(9), 352; https://doi.org/10.3390/antiox8090352 - 01 Sep 2019
Abstract
The phenolic composition of virgin olive oil (VOO) is strongly determined by the content and distribution of secoiridoid phenolic glucosides present in the olive fruit. Among them, oleuropein is the most abundant in olive mesocarp and is characterized by containing an hydroxytyrosol residue [...] Read more.
The phenolic composition of virgin olive oil (VOO) is strongly determined by the content and distribution of secoiridoid phenolic glucosides present in the olive fruit. Among them, oleuropein is the most abundant in olive mesocarp and is characterized by containing an hydroxytyrosol residue in its chemical structure. Hydroxytyrosol-containing molecules are those that exhibit the most important biological activities in virgin olive oil. In this regard, we identified an aromatic aldehyde synthase gene (OeAAS) from an olive transcriptome, which was synthesized, expressed in Eschrichia coli, and purified its encoded protein. The recombinant OeAAS is a bifunctional enzyme catalyzing decarboxylation and amine-oxidation reactions in a single step. OeAAS displays strict substrate specificity for l-DOPA to form 2,4-dihydroxyphenylacetaldehyde, the immediate precursor of hydroxytyrosol. In addition to the biochemical characterization of the enzyme, the expression analysis carried out in different olive cultivars and ripening stages indicate that OeAAS gene is temporally regulated in a cultivar-dependent manner. High correlation coefficients were found between OeAAS expression levels and the phenolic content of olive fruits and oils, which supports a key role for OeAAS in the accumulation of hydroxytyrosol-derived secoiridoid compounds in olive fruit and virgin olive oil. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Figure 1

Open AccessArticle
Nitrogen Headspace Improves the Extra Virgin Olive Oil Shelf-Life, Preserving Its Functional Properties
Antioxidants 2019, 8(9), 331; https://doi.org/10.3390/antiox8090331 - 22 Aug 2019
Abstract
The functional foods field has recently evolved due to new research being carried out in the food area and greater regulations; these factors have contributed to the creation of health claims, and to the increasing attention that consumers give to health-promoting food products. [...] Read more.
The functional foods field has recently evolved due to new research being carried out in the food area and greater regulations; these factors have contributed to the creation of health claims, and to the increasing attention that consumers give to health-promoting food products. The aim of this research was to improve the shelf-life of a typical functional food of the Mediterranean diet, the Extra Virgin Olive Oil (EVOO). We focused our attention on the standardization and validation of a production process, starting from the cultivation and harvesting of the olives, which would guarantee a product of quality in terms of bioactive compound content. Furthermore, a methodology/procedure to preserve them in the best way over a long period of time, in order to guarantee the consumer receives a product that retains its functional and organoleptic native properties, was evaluated. The monitoring of biological cultivations, harvesting, milling process, and storage, as well as careful quality control of the analytical parameters (e.g., contents of polyphenols, α-tocopherol, fatty acids, acidity, peroxides, dienes, trienes, ΔK, and antioxidant power) showed that, under the same conditions, a nitrogen headspace is a discriminating factor for the maintenance of the functional properties of EVOO. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Open AccessArticle
Water Stress, Irrigation and Concentrations of Pentacyclic Triterpenes and Phenols in Olea europaea L. cv. Picual Olive Trees
Antioxidants 2019, 8(8), 294; https://doi.org/10.3390/antiox8080294 - 08 Aug 2019
Abstract
Pentacyclic triterpenes and phenols are two types of bioactive molecules found in olive trees that have important activities related to health and disease prevention. Triterpenes, including oleanolic acid, maslinic acid, erythrodiol and uvaol, show antitumoral activities, and phenols such as oleuropein, tyrosol, and [...] Read more.
Pentacyclic triterpenes and phenols are two types of bioactive molecules found in olive trees that have important activities related to health and disease prevention. Triterpenes, including oleanolic acid, maslinic acid, erythrodiol and uvaol, show antitumoral activities, and phenols such as oleuropein, tyrosol, and hydroxytyrosol are natural antioxidants. The concentration of these metabolites is considered a marker of the quality of olives and olive oil. In recent years, a lack of rain water has caused important economic losses relating to olive trees grown in Jaén, Spain. In this work, we investigated the effect of water stress by drought on the concentration of pentacyclic triterpenes and phenols in the fruits, leaves, stems and roots of cv. Picual olive trees, by comparing the concentration found in water-stressed versus irrigated plants. We used HPLC-UV/Vis and HPLC-MS to identify and determine the concentration of each individual compound. Our results showed that important changes in the concentration of these compounds are produced in response to water stress in different organs. The total content of most of these compounds in the fruits was significantly reduced, affecting their quality and production. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Figure 1

Open AccessArticle
Diet and Oxidative Status. The Dietary Pattern and Urinary 8-Isoprostane in Healthy Spanish Women
Antioxidants 2019, 8(8), 271; https://doi.org/10.3390/antiox8080271 - 02 Aug 2019
Abstract
The Mediterranean diet is associated with a low incidence of physiologic and metabolic non-communicable diseases such as hypertension, obesity, and insulin resistance. These chronic diseases are closely related to oxidative status, which is determined by the balance between oxidant and antioxidant levels. The [...] Read more.
The Mediterranean diet is associated with a low incidence of physiologic and metabolic non-communicable diseases such as hypertension, obesity, and insulin resistance. These chronic diseases are closely related to oxidative status, which is determined by the balance between oxidant and antioxidant levels. The Mediterranean diet is rich in foods with important antioxidant properties, such as fruits and extra virgin olive oil. The aim of this work was to establish the relationship between dietary patterns, the total intake of polyphenols, and the levels of 8-isoprostanes in urine, as a marker of lipid peroxidation, in a group of healthy Spanish women. The main sources of dietary polyphenols were fruits, vegetables, pulses, nuts, and extra virgin olive oil. There was a significant and positive correlation between the estimated intake of polyphenols, total polyphenols excreted in urine, adherence to the Mediterranean diet, and the intake of specific food groups. A positive correlation was established between the total polyphenols in urine and the intake of raw extra virgin olive oil. However, a negative correlation was established between the amount of 8-isoprostanes in urine, total intake of polyphenols, adherence to the Mediterranean diet, and the intake of fruits and nuts. These results indicate an association between oxidative status and the intake of foods that are typical of the Mediterranean diet, in healthy women. Furthermore, the results demonstrate the use of urine 8-isoprostanes as a marker of adherence to the Mediterranean diet. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Open AccessArticle
Changes in the Antioxidant Properties of Extra Virgin Olive Oil after Cooking Typical Mediterranean Vegetables
Antioxidants 2019, 8(8), 246; https://doi.org/10.3390/antiox8080246 - 26 Jul 2019
Abstract
Extra virgin olive oil (EVOO), water, and a water/oil mixture (W/O) were used for frying, boiling and sautéeing Mediterranean vegetables (potato, pumpkin, tomato and eggplant). Differences in antioxidant capacity (AC) (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric iron (FRAP), 2,2-azinobis-(3-ethylbensothiazoline)-6-sulphonic acid (ABTS)), total phenolic content (TPC) and [...] Read more.
Extra virgin olive oil (EVOO), water, and a water/oil mixture (W/O) were used for frying, boiling and sautéeing Mediterranean vegetables (potato, pumpkin, tomato and eggplant). Differences in antioxidant capacity (AC) (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric iron (FRAP), 2,2-azinobis-(3-ethylbensothiazoline)-6-sulphonic acid (ABTS)), total phenolic content (TPC) and individual phenols (high-performance liquid chromatography (HPLC)) in unused and used EVOO and water were determined. The water used to boil tomatoes showed the highest TPC value, whilst the lowest was found in the EVOO from the W/O used for boiling potatoes. After processing, the concentrations of phenols exclusive to EVOO diminished to different extents. There was a greater transfer of phenols from the vegetable to the oil when eggplant, tomato and pumpkin were cooked. W/O boiling enriched the water for most of the phenols analysed, such as chlorogenic acid and phenols exclusive to EVOO. The values of AC decreased or were maintained when fresh oil was used to cook the vegetables (raw > frying > sautéing > boiling). The water fraction was enriched in 6-hydroxy-2,5,7,8–tetramethyl-chroman-2-carboxylic acid (Trolox) equivalents following boiling, though to a greater extent when EVOO was added. Phenolic content and AC of EVOO decreased after cooking Mediterranean diet vegetables. Further, water was enriched after the boiling processes, particularly when oil was included. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Open AccessArticle
Analysis of Olive (Olea Europaea L.) Genetic Resources in Relation to the Content of Vitamin E in Virgin Olive Oil
Antioxidants 2019, 8(8), 242; https://doi.org/10.3390/antiox8080242 - 25 Jul 2019
Abstract
Virgin olive oil (VOO) is the main source of lipids in the Mediterranean diet and one of the main contributors to its proven protection against diseases associated with chronic inflammation states. This oil is rich in antioxidant compounds such as tocopherols, which together [...] Read more.
Virgin olive oil (VOO) is the main source of lipids in the Mediterranean diet and one of the main contributors to its proven protection against diseases associated with chronic inflammation states. This oil is rich in antioxidant compounds such as tocopherols, which together constitute the vitamin E stock of the oil. The purpose of the present work was to conduct a study on the diversity of the contents of vitamin E in the olive species (Olea europaea L.), and to know how the season climatic conditions and the degree of fruit ripening stage influences the final content of this vitamin in VOO. Data showed that the content of vitamin E in VOO is highly dependent on the olive cultivar, displaying a wide variability (89–1410 mg tocopherol/kg oil) in the olive species, and that is also dependent, to a lesser extent, on the crop year climate and the stage of fruit ripening. In addition, the suitability of cultivar crosses for breeding programs to obtain new cultivars with improved vitamin E content in VOO has been assessed. Our findings demonstrated that a single cross of olive cultivars may provide sufficient variability to be used in the selection of new cultivars. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Open AccessArticle
Composition and Antioxidant Properties of Spanish Extra Virgin Olive Oil Regarding Cultivar, Harvest Year and Crop Stage
Antioxidants 2019, 8(7), 217; https://doi.org/10.3390/antiox8070217 - 11 Jul 2019
Abstract
The health benefits of extra virgin olive oil (EVOO) are related to its chemical composition and the presence of bioactive compounds with antioxidant properties. The aim of this study was to evaluate antioxidant compounds (pigments, coenzyme Q10 (CoQ10) and phenolic [...] Read more.
The health benefits of extra virgin olive oil (EVOO) are related to its chemical composition and the presence of bioactive compounds with antioxidant properties. The aim of this study was to evaluate antioxidant compounds (pigments, coenzyme Q10 (CoQ10) and phenolic compounds) and antioxidant properties of EVOO from the same region comparing different cultivars (Hojiblanca and Arbequina), harvest year and crop stage. Antioxidant properties of oils were studied before and after a gastrointestinal digestion process, by in vitro assays (DPPH, ABTS and FRAP) and antioxidant markers in Caco-2 cells (reactive oxygen species production). The content of bioactive compounds measured was significantly affected by cultivar and harvest year (except for carotenoids) and by the crop stage (except for coenzyme Q10). Higher amounts of coenzyme Q10 were observed in Hojiblanca than in Arbequina EVOO. Total phenol content and antioxidant properties were also different depending on cultivar and harvest year and the in vitro digestion process strongly improved antioxidant marker values. Antioxidant potential in bioaccessible fractions was mainly related to the content of coenzyme Q10 and phenolic compounds in EVOO. Chemometric analysis showed that the oils were clearly classified by cultivars, harvest and crop stage, according to the chemical composition and antioxidant activity analyzed in the present study. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Open AccessArticle
Phenolic Profile and Antioxidant Activity of Italian Monovarietal Extra Virgin Olive Oils
Antioxidants 2019, 8(6), 161; https://doi.org/10.3390/antiox8060161 - 05 Jun 2019
Abstract
In the last years, the interest in Italian monovarietal oils has increased due to their specific organoleptic qualities. Extra virgin olive oils (EVOOs) are rich in phenolic compounds, secondary metabolites well known and studied for their nutraceutical properties. However, among EVOOs, there is [...] Read more.
In the last years, the interest in Italian monovarietal oils has increased due to their specific organoleptic qualities. Extra virgin olive oils (EVOOs) are rich in phenolic compounds, secondary metabolites well known and studied for their nutraceutical properties. However, among EVOOs, there is great variability in phenolic composition due to the origin, the production technique, and mainly, the genotype. The aim of this work was to evaluate the different phenolic profiles and the antioxidant activities of monovarietal oils. The results confirm this variability. In fact, the overall content of oleuropein varies up to four times between the different genotypes (from 33.80 to 152.32 mg/kg oil), while the oleocanthal content is significant only in two oils. The antioxidant activity, determined with 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays, is correlated with the content of total phenolic substances, with half maximal inhibitory concentration (IC50) values for the DPPH test ranging from 160 to 91 mg of oil, while the ORAC test shows values between 5.45 and 8.03 μmol Trolox equivalent (TE)/g oil. Full article
(This article belongs to the Special Issue Antioxidants in Olive Oils)
Show Figures

Graphical abstract

Back to TopTop