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Antioxidant Capacity of Phytochemicals in Fruits and Vegetables

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Food Chemistry".

Deadline for manuscript submissions: closed (31 January 2023) | Viewed by 25680

Special Issue Editors


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Guest Editor
MARE-Marine and Environmental Sciences Centre, Polytechnic University of Leiria, 2520-630 Peniche, Portugal
Interests: chemistry of marine natural products; extraction and fractionation; purification and identification of phytochemicals; nutraceuticals; in vitro antioxidant activity
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
MARE-Marine and Environmental Sciences Centre, Polytechnic University of Leiria, 2520-630 Peniche, Portugal
Interests: nutraceuticals; functional foods; foods formulation; antioxidant activity; health benefits
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the years, fruits and vegetables have been promoted for their richness in terms of nutritional composition, sensorial properties, and presence of health-promoting compounds, combining the nutritious role with health benefits through their inclusion in daily diet.

It is well established that many phytochemicals found in fruits and vegetables, e.g., phenolics, anthocyanins, carotenoids, tocopherols, ascorbic acid, among others, are critical to counteract the deleterious effects of oxidative stress events involved in several chronic diseases like cancer, diabetes, cardiovascular, and neurodegenerative disorders. Into this framework, new insights into the antioxidant capacity of natural phytochemicals remain a current topic.

Contributions to this Special Issue can cover innovative and promising studies related to phytochemicals extraction methodologies, chemical characterization and quantification, antioxidant capacity determination, mechanisms of action, and bioaccessibility/bioavailability studies. Evaluations of the phytochemical composition correlated with antioxidant capacity along different moments of the fruit and vegetable chain value, namely, preharvest (maturity stage, agricultural techniques, ripening time) and postharvest (preservation treatment) will also be considered.

 

This Special Issue will include original articles, reviews, and short communications related to the characterization, antioxidant capacity, and health-promoting properties of phytochemicals found in fruits and vegetables.

Dr. Alice Martins
Dr. Joaquina Pinheiro
Guest Editors

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Keywords

  • Antioxidant compounds
  • Phenolic acids
  • Flavonoids
  • Oxidative stress
  • Free radicals
  • Health benefits
  • Preharvest
  • Postharvest
  • Preservation technologies

Published Papers (9 papers)

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Research

12 pages, 4493 KiB  
Article
Effect of Esculetin on Tert-Butyl Hydroperoxide-Induced Oxidative Injury in Retinal Pigment Epithelial Cells In Vitro
by Woo Kwon Jung, Su-Bin Park, Hwa Young Yu, Yong Hwan Kim and Junghyun Kim
Molecules 2022, 27(24), 8970; https://doi.org/10.3390/molecules27248970 - 16 Dec 2022
Cited by 2 | Viewed by 1276
Abstract
Esculetin is a coumarin-derived compound with antioxidant and anti-inflammatory properties. The current study aims to evaluate the therapeutic implications of esculetin on retinal dysfunction and uncover the underlying mechanisms. Tert-butyl hydroperoxide (t-BHP) at a concentration of 300 μM was used [...] Read more.
Esculetin is a coumarin-derived compound with antioxidant and anti-inflammatory properties. The current study aims to evaluate the therapeutic implications of esculetin on retinal dysfunction and uncover the underlying mechanisms. Tert-butyl hydroperoxide (t-BHP) at a concentration of 300 μM was used to induce oxidative stress in human retinal pigment epithelial cell line (ARPE-19) cells. Esculetin at concentrations below 250 μM did not cause cytotoxicity to ARPE-19 cells. Cell viability analysis confirmed that t-BHP induced oxidative injury of ARPE-19 cells. However, ARPE-19 cells were protected from t-BHP-induced oxidative injury by esculetin in a concentration-dependent manner. As a result of the TUNEL assay to confirm apoptosis, esculetin treatment reduced the number of TUNEL-positive cells. Esculetin down-regulated the expression levels of Bax, Caspase-3, and PARP and up-regulated the expression level of Bcl2. Collectively, this study demonstrates that esculetin exerts potent antioxidant properties in ARPE-19 cells, inhibiting t-BHP-induced apoptosis under the regulation of apoptotic factors. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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15 pages, 3180 KiB  
Article
Photo-Protective and Anti-Inflammatory Effects of Antidesma thwaitesianum Müll. Arg. Fruit Extract against UVB-Induced Keratinocyte Cell Damage
by Sutthibhon Natewong, Cholticha Niwaspragrit, Piyanee Ratanachamnong, Papavee Samatiwat, Poommaree Namchaiw and Yamaratee Jaisin
Molecules 2022, 27(15), 5034; https://doi.org/10.3390/molecules27155034 - 8 Aug 2022
Cited by 6 | Viewed by 2153
Abstract
The main cause of most skin cancers is damage from UVB from sunlight, which penetrate the skin surface and induce inflammation. For this reason, this study aims to identify natural products with photo-protection properties and their mode of action by using the UVB-irradiated [...] Read more.
The main cause of most skin cancers is damage from UVB from sunlight, which penetrate the skin surface and induce inflammation. For this reason, this study aims to identify natural products with photo-protection properties and their mode of action by using the UVB-irradiated HaCaT keratinocyte model. Antidesma thwaitesianum fruit extracts at 25, 50, and 100 µg/mL recovered cell viability following UVB exposure in a dose-dependent manner. Cell survival was associated with the reduction in intracellular ROS and NO. In addition, we showed that the pre-treatment with the fruit extract lowered the phosphorylation level of two MAPK-signaling pathways: p38 MAPKs and JNKs. The resulting lower MAPK activation decreased their downstream pro-inflammatory cascade through COX-2 expression and subsequently reduced the PGE2 proinflammatory mediator level. The photoprotective effects of the fruit extract were correlated with the presence of polyphenolic compounds, including cyanidin, ferulic acid, caffeic acid, vanillic acid, and protocatechuic acid, which have been previously described as antioxidant and anti-inflammation. Together, we demonstrated that the pre-treatment with the fruit extract had photo-protection by inhibiting oxidative stress and subsequently lowered stress-induced MAPK responses. Therefore, this fresh fruit is worthy of investigation to be utilized as a skincare ingredient for preventing UVB-induced skin damage. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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11 pages, 1813 KiB  
Article
Metabolic Profiling and Transcriptional Analysis of Carotenoid Accumulation in a Red-Fleshed Mutant of Pummelo (Citrus grandis)
by Congyi Zhu, Cheng Peng, Diyang Qiu and Jiwu Zeng
Molecules 2022, 27(14), 4595; https://doi.org/10.3390/molecules27144595 - 19 Jul 2022
Cited by 4 | Viewed by 1461
Abstract
Citrus grandis ‘Tomentosa’, commonly known as ‘Huajuhong’ pummelo (HJH), is used in traditional Chinese medicine and can moisten the lungs, resolve phlegm, and relieve coughs. A spontaneous bud mutant, named R-HJH, had a visually attractive phenotype with red albedo tissue and red juice [...] Read more.
Citrus grandis ‘Tomentosa’, commonly known as ‘Huajuhong’ pummelo (HJH), is used in traditional Chinese medicine and can moisten the lungs, resolve phlegm, and relieve coughs. A spontaneous bud mutant, named R-HJH, had a visually attractive phenotype with red albedo tissue and red juice sacs. In this study, the content and composition of carotenoids were investigated and compared between R-HJH and wild-type HJH using HPLC–MS analysis. The total carotenoids in the albedo tissue and juice sacs of R-HJH were 4.03- and 2.89-fold greater than those in HJH, respectively. The massive accumulation of carotenoids, including lycopene, β-carotene and phytoene, led to the attractive red color of R-HJH. However, the contents of flavones, coumarins and most volatile components (mainly D-limonene and γ-terpinene) were clearly reduced in R-HJH compared with wild-type HJH. To identify the molecular basis of carotenoid accumulation in R-HJH, RNA-Seq transcriptome sequencing was performed. Among 3948 differentially expressed genes (DEGs), the increased upstream synthesis genes (phytoene synthase gene, PSY) and decreased downstream genes (β-carotene hydroxylase gene, CHYB and carotenoid cleavage dioxygenase gene, CCD7) might be the key factors that account for the high level of carotenoids in R-HJH. These results will be beneficial for determining the molecular mechanism of carotenoid accumulation and metabolism in pummelo. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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17 pages, 383 KiB  
Article
Phytonutrients, Colorant Pigments, Phytochemicals, and Antioxidant Potential of Orphan Leafy Amaranthus Species
by Umakanta Sarker, Md. Golam Rabbani, Shinya Oba, Wagdy M. Eldehna, Sara T. Al-Rashood, Nada M. Mostafa and Omayma A. Eldahshan
Molecules 2022, 27(9), 2899; https://doi.org/10.3390/molecules27092899 - 2 May 2022
Cited by 44 | Viewed by 2843
Abstract
The underutilized Amaranthus leafy vegetables are a unique basis of pigments such as β-cyanins, β-xanthins, and betalains with radical scavenging capacity (RSC). They have abundant phytonutrients and antioxidant components, such as pigments, vitamins, phenolics, and flavonoids. Eight selected genotypes (four genotypes from each [...] Read more.
The underutilized Amaranthus leafy vegetables are a unique basis of pigments such as β-cyanins, β-xanthins, and betalains with radical scavenging capacity (RSC). They have abundant phytonutrients and antioxidant components, such as pigments, vitamins, phenolics, and flavonoids. Eight selected genotypes (four genotypes from each species) of underutilized Amaranthus leafy vegetables were evaluated for phytonutrients, pigments, vitamins, phenolics, flavonoids, and antioxidants in a randomized complete block design under ambient field conditions with three replicates. The studied traits showed a wide range of variations across eight genotypes of two species of Amaranthus leafy vegetables. The highest fat, β-xanthins, K, dietary fiber, Mg, β-cyanins, Mn, chlorophyll ab, Zn, TP, TF, betalains, chlorophyll a content, and (RSC) (DPPH) and RSC (ABTS+) were obtained from A. tricolor accessions. Conversely, the highest protein, Cu, carbohydrates, Ca, and chlorophyll b content were obtained from A. lividus accessions. The highest dry matter, carotenoids, Fe, energy, and ash were obtained from A. tricolor and A. lividus. The accession AT2 confirmed the highest vit. C and RSC (DPPH) and RSC (ABTS+); AT5 had the highest TP content; and AT12 had the highest TF content. A. tricolor accessions had high phytochemicals across the two species, such as phytopigments, vitamins, phenolics, antioxidants, and flavonoids, with considerable nutrients and protein. Hence, A. tricolor accessions can be used as high-yielding cultivars comprising ample antioxidants. The correlation study revealed that vitamin C, pigments, flavonoids, β-carotene, and phenolics demonstrated a strong RSC, and showed a substantial contribution to the antioxidant potential (AP) of A. tricolor. The investigation exposed that the accessions displayed a plentiful origin of nutritional values, phytochemicals, and AP with good quenching ability of reactive oxygen species (ROS) that provide enormous prospects for nourishing the mineral-, antioxidant-, and vitamin-threatened community. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
17 pages, 24719 KiB  
Article
Changes in Physicochemical, Free Radical Activity, Total Phenolic and Sensory Properties of Orange (Citrus sinensis L.) Juice Fortified with Different Oleaster (Elaeagnus angustifolia L.) Extracts
by Maryam Sarvarian, Afshin Jafarpour, Chinaza Godswill Awuchi, Ademiku O. Adeleye and Charles Odilichukwu R. Okpala
Molecules 2022, 27(5), 1530; https://doi.org/10.3390/molecules27051530 - 24 Feb 2022
Cited by 20 | Viewed by 2490
Abstract
In Iran and other parts of Western Asia, the oleaster (Elaeagnus angustifolia L.) fruit is processed in the dried powdery form, and in recent times, increasingly applied/sprinkled in fruit juices such as those made from oranges (Citrus sinensis L.). To our [...] Read more.
In Iran and other parts of Western Asia, the oleaster (Elaeagnus angustifolia L.) fruit is processed in the dried powdery form, and in recent times, increasingly applied/sprinkled in fruit juices such as those made from oranges (Citrus sinensis L.). To our best knowledge, the effectiveness of oleaster fruit extract in fortifying the orange juice has not yet been reported and the knowledge of this will greatly benefit the consumers, particularly those around the Western Asia region. This current work, therefore, investigated the changes in physicochemical, free radical activity, total phenolic compounds, and sensory properties of orange juice fortified with different oleaster fruit extracts. The orange juice mix formulation comprised different concentrations (5, 10, 15, 20, and 25%) of oleaster (alcoholic, aqueous, and hydro-alcoholic) extracts. The control comprised orange concentrate (4% w/v), sugar (8.5% w/v), and citric acid (0.1% w/v) brought to the desirable volume with water. As the free radical activity depicted the antioxidant properties, the physicochemical aspects of this work involved the determinations of Brix, density, ash, pH, total acidity, sucrose, and total sugar, whereas the sensory aspects involved the determinations of color and taste. Whilst the aqueous oleaster 20 and 25% extracts produced notable physicochemical differences in the orange juice mix, both free radical activity, and phenolic compounds significantly increased (p < 0.05) after 30 days despite resembling (p > 0.05) those of control at day 1. More so, the increases in aqueous, alcoholic, and hydro-alcoholic oleaster extracts would decrease (p < 0.05) the sensory color and taste of the orange juice mix in this study. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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13 pages, 963 KiB  
Article
Contribution to the Evaluation of Physicochemical Properties, Total Phenolic Content, Antioxidant Potential, and Antimicrobial Activity of Vinegar Commercialized in Morocco
by Mohammed Kara, Amine Assouguem, Mohamed El Fadili, Safaâ Benmessaoud, Samar Zuhair Alshawwa, Omkulthom Al Kamaly, Hamza Saghrouchni, Abdou Rachid Zerhouni and Jamila Bahhou
Molecules 2022, 27(3), 770; https://doi.org/10.3390/molecules27030770 - 25 Jan 2022
Cited by 15 | Viewed by 2778
Abstract
Vinegar is a natural product widely used in food and traditional medicine thanks to its physicochemical properties and its richness in bioactive molecules. However, its direct use by consumers can have complications and undesirable effects. Therefore, this study contributes to investigating the physicochemical [...] Read more.
Vinegar is a natural product widely used in food and traditional medicine thanks to its physicochemical properties and its richness in bioactive molecules. However, its direct use by consumers can have complications and undesirable effects. Therefore, this study contributes to investigating the physicochemical and biological properties of eleven vinegars marketed in Morocco. Determination of pH, acetic acid, conductivity, total soluble solids and alcohol content in vinegar was carried out. The polyphenols (TP), flavonoids (TF), and condensed tannins (CT) content was determined, and their antioxidant activities were evaluated using 2,2-diphenyl-1-picryl Hydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP) and Phosphomolybdenum Reduction Assay (TAC). Then, the antimicrobial activity was studied against four pathogenic bacteria and two fungal strains, using the disk diffusion and the microdilution method. This study showed a wide range of acetic acid values from 0.65 ± 0.29 to 5.15 ± 0.20%. The high value of TP, TF, and CT in our samples V10, V9, and V4 was 655.00 ± 22.2 µgGAE/mL, 244.53 ± 11.32 µgQE/mL and 84.63 ± 1.00 µgTAE/mL, respectively. The tested strains showed variable sensitivities to the different samples with inhibition zones ranging from 6.33 ± 2.08 to 34.33 ± 0.58 mm. The lowest minimum inhibition concentrations were recorded against Staphylococcus aureus ATCC29213 ranging from 1.95 to 7.81 µL/mL. While Aspergillus niger ATCC16404 showed resistance against all of the analyzed samples. In general, vinegar commercialized in Morocco presents a variable range of products with variable properties. Indeed, must take into account this diversity when using it. A future study is needed to identify the phytochemical composition that will further the comprehension of this variability and contribute to its valorization. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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14 pages, 2649 KiB  
Article
Dynamic Changes in Anthocyanin Accumulation and Cellular Antioxidant Activities in Two Varieties of Grape Berries during Fruit Maturation under Different Climates
by Liuwei Qin, Hui Xie, Nan Xiang, Min Wang, Shouan Han, Mingqi Pan, Xinbo Guo and Wen Zhang
Molecules 2022, 27(2), 384; https://doi.org/10.3390/molecules27020384 - 7 Jan 2022
Cited by 8 | Viewed by 1841
Abstract
As popularly consumed fruit berries, grapes are widely planted and processed into products, such as raisins and wine. In order to identify the influences of different climatic conditions on grape coloring and quality formation, we selected two common varieties of grape berries, ‘Red [...] Read more.
As popularly consumed fruit berries, grapes are widely planted and processed into products, such as raisins and wine. In order to identify the influences of different climatic conditions on grape coloring and quality formation, we selected two common varieties of grape berries, ‘Red Globe’ and ‘Xin Yu’, for investigation. Grapes were separately grown in different climates, such as a temperate continental arid climate and a temperate continental desert climate, in Urumqi and Turpan, China, for five developmental stages. As measured, the average daily temperature and light intensity were lower in Urumqi. Urumqi grape berries had a lower brightness value (L*) and a higher red-green value (a*) when compared to Turpan’s. A RT-qPCR analysis revealed higher transcriptions of key genes related to anthocyanin biosynthesis in Urumqi grape berries, which was consistent with the more abundant phenolic substances, especially anthocyanins. The maximum antioxidant activity in vitro and cellular antioxidant activity of grape berries were also observed in Urumqi grape berries. These findings enclosed the influence of climate on anthocyanin accumulation and the antioxidant capacity of grapes, which might enlarge our knowledge on the quality formation of grape berries and might also be helpful for cultivating grapes with higher nutritional value. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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14 pages, 1140 KiB  
Article
Physicochemical, Antioxidant, Microstructural Properties and Bioaccessibility of Dark Chocolate with Plant Extracts
by Szymon Poliński, Sylwia Kowalska, Patrycja Topka and Aleksandra Szydłowska-Czerniak
Molecules 2021, 26(18), 5523; https://doi.org/10.3390/molecules26185523 - 11 Sep 2021
Cited by 10 | Viewed by 3281
Abstract
In this study, dark chocolates (DCh) containing zinc lactate (ZnL) were enriched with extracts from elderberries (EFrE), elderflowers (EFlE), and chokeberries (ChFrE) to improve their functional properties. Both dried plant extracts and chocolates were analyzed for antioxidant capacity (AC) using four different analytical [...] Read more.
In this study, dark chocolates (DCh) containing zinc lactate (ZnL) were enriched with extracts from elderberries (EFrE), elderflowers (EFlE), and chokeberries (ChFrE) to improve their functional properties. Both dried plant extracts and chocolates were analyzed for antioxidant capacity (AC) using four different analytical methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric ion-reducing antioxidant capacity (CUPRAC), and ferric-reducing antioxidant power (FRAP), while total phenolic content (TPC) was determined by Folin–Ciocalteu (F–C) assay. An increase in antioxidant properties of fortified chocolates was found, and the bioaccessibility of their antioxidants was evaluated. The highest AC and TPC were found in ChFrE and chocolate with chokeberries (DCh + ChFrE) before and after simulated in vitro digestion. Bioaccessibility studies indicated that during the simulated digestion the AC of all chocolates reduced significantly, whereas insignificant differences in TPC results were observed between chemical and physiological extracts. Moreover, the influence of plant extracts on physicochemical parameters such as moisture content (MC), fat content (FC), and viscosity of chocolates was estimated. Furthermore, scanning electron microscopy with dispersive energy spectroscopy (SEM-EDS) was used to analyze surface properties and differences in the chemical composition of chocolates without and with additives. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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17 pages, 1401 KiB  
Article
Pineapple (Ananas comosus L.) By-Products Valorization: Novel Bio Ingredients for Functional Foods
by Diana I. Santos, Cátia F. Martins, Renata A. Amaral, Luísa Brito, Jorge A. Saraiva, António A. Vicente and Margarida Moldão-Martins
Molecules 2021, 26(11), 3216; https://doi.org/10.3390/molecules26113216 - 27 May 2021
Cited by 10 | Viewed by 6086
Abstract
Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30–50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse [...] Read more.
Pineapple is consumed on a large scale around the world due to its appreciated sensorial characteristics. The industry of minimally processed pineapple produces enormous quantities of by-products (30–50%) which are generally undervalued. The end-of-life of pineapple by-products (PBP) can be replaced by reuse and renewal flows in an integrated process to promote economic growth by reducing consumption of natural resources and diminishing food waste. In our study, pineapple shell (PS) and pineapple core (PC), vacuum-packed separately, were subjected to moderate hydrostatic pressure (225 MPa, 8.5 min) (MHP) as abiotic stress to increase bromelain activity and antioxidant capacity. Pressurized and raw PBP were lyophilized to produce a stable powder. The dehydrated samples were characterized by the following methodologies: chemical and physical characterization, total phenolic compounds (TPC), antioxidant capacity, bromelain activity, microbiology, and mycotoxins. Results demonstrated that PBP are naturally rich in carbohydrates (66–88%), insoluble (16–28%) and soluble (2–4%) fiber, and minerals (4–5%). MHP was demonstrated to be beneficial in improving TPC (2–4%), antioxidant activity (2–6%), and bromelain activity (6–32%) without affecting the nutritional value. Furthermore, microbial and mycotoxical analysis demonstrated that powdered PC is a safe by-product. PS application is possible but requires previous decontamination to reduce the microbiological load. Full article
(This article belongs to the Special Issue Antioxidant Capacity of Phytochemicals in Fruits and Vegetables)
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