Submit to Applied Sciences Review for Applied Sciences Propose a Special Issue

Journal Browser

New Insights into Natural Antioxidants in Foods

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Related Special Issue
Published Papers

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Food Science and Technology".

Deadline for manuscript submissions: closed (20 June 2023) | Viewed by 19403

Share This Special Issue

Special Issue Editor

Dr. Małgorzata Muzolf-Panek

E-Mail Website
Guest Editor

Department of Food Quality and Safety Management, Poznań University of Life Sciences, ul. Wojska polskiego 28, 60-637 Poznań, Poland
Interests: polyphenols (mainly catechins and anthocyanins); natural antioxidants of plant origin; antioxidant activity (effect of chemical structure on the antioxidant activity, interactions of antioxidants with other compounds); effect of natural antioxidants on food quality during storage; extraction of antioxidant-active compounds from plant material
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Increasing awareness of consumers on the effect of food components on human health and increasing demands of innovations have led the food industry to change its strategy and offer allegedly “natural” and “clean label” products. These marketing catchwords are often used to describe food with naturally derived bioactive compounds, including natural antioxidants. Therefore, the efforts of scientists and the food industry have been focused on searching for new sources of natural antioxidants (mainly of plant origin) and new methods of incorporation of the antioxidant-active compounds into food. Natural antioxidants can easily minimize the addition of chemical preservatives to food. This approach has gained consumers’ acceptance, even though the sensory attributes of such “natural” food have changed in terms of sensory properties. Most natural antioxidants are derived from plant resources and include various compounds such as vitamins, polyphenols, phenolic acids, enzymes, and low-molecular antioxidants. However, “nature-origin” antioxidants are also obtained from enzymatic hydrolysis of protein (peptides). The broad range of natural antioxidant-active compounds results in various mechanisms of antioxidant action in food, such as free radical scavenging, scavenging of molecular oxygen, chelating transition metal ions, regeneration of other antioxidants (such as tocopherols), and finally, inhibition of pro-oxidant enzymes. Moreover, the final antioxidant effect in food is the result of various factors, such as concentration of antioxidants, interaction with food constituents, mode of incorporation (direct or indirect) into food products, and storage conditions.

The aim of this Special Issue is to bring new insights into natural antioxidants in food in terms of new sources of these compounds, extraction and purification techniques from various materials, new application strategies in food (biofilms, nanocapsules, etc.), interaction of natural antioxidants with other compounds in the food matrix (e.g., polyphenols–proteins interaction), and finally, development of mathematical models for describing changes to the antioxidant activity of food products during storage.

Researchers are encouraged to submit both original research and review articles that report results in the field of natural antioxidants in food.

Dr. Małgorzata Muzolf-Panek
Guest Editor

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 submissions that pass pre-check are 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. Applied Sciences is an international peer-reviewed open access semimonthly 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 2400 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.

Related Special Issue

New Insights into Natural Antioxidants in Foods: 2nd Edition in Applied Sciences (3 articles)

Published Papers (14 papers)

Download All Papers

Research

17 pages, 1156 KiB

Open AccessArticle

Nitrogen Metabolism and Antioxidant Capacity of Selected Vegetables from Organic and Conventional Crops

by Tamara Chadzinikolau and Magda Formela-Luboińska

Appl. Sci. 2023, 13(20), 11170; https://doi.org/10.3390/app132011170 - 11 Oct 2023

Cited by 2 | Viewed by 899

Abstract

The study aimed to determine the level of selected indicators of nitrogen metabolism in vegetables from organic (organic food store) and conventional (supermarket and local market) crops. Nitrates, total chlorophyll content, and the activity of the nitrate biosynthesis pathway enzymes—nitrate reductase (NR) and glutamine synthetase (GS)—were determined in the leaves of selected species from different plant families. The research material consisted of dill, carrot, celery, beet, onion, Chinese and white cabbage, and rocket. The nitrate content was within the permissible limits, except for vegetables bought at a local market. In most cases, no significant differences in the level of nitrates between organic and conventional farming were observed. The analyses revealed the highest nitrate content in dill [2.16 mg × g⁻¹] and the lowest in onions [0.06 mg × g⁻¹] from conventional crops. The enzyme activities were related to the level of nitrates. The analysed species differed in phenolic compounds, ascorbate levels, and total antioxidant capacity (TCA). Positive correlations were found between TCA and antioxidants. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

15 pages, 3052 KiB

Open AccessArticle

Acid-Catalyzed Organosolv Treatment of Potato Peels to Boost Release of Polyphenolic Compounds Using 1- and 2-Propanol

by Selma Casasni, Akram Guenaoui, Spyros Grigorakis and Dimitris P. Makris

Appl. Sci. 2023, 13(16), 9484; https://doi.org/10.3390/app13169484 - 21 Aug 2023

Viewed by 957

Abstract

The current study aimed at developing an effective organosolv treatment, with the objective to obtain potato peel extracts highly enriched in polyphenols. To this end, two low-cost solvents were employed, 1- and 2-propanol, which are considered green, but they have been rather poorly studied compared to other conventional solvents, such as ethanol. Treatment development also embraced the use of sulfuric acid, a well-examined catalyst in organosolv processes. Treatment evaluation on the basis of response surface optimization and severity demonstrated that 1-propanol was a more effective solvent, providing a maximum yield in total polyphenols of 19.28 mg chlorogenic acid equivalents per g of dry potato peel weight, attained with 40% 1-propanol/1.5% (w/v) sulfuric acid at a treatment time of 60 min and a temperature of 90 °C. This treatment was of lower severity compared to the one with 2-propanol, and it also provided almost 24% higher total polyphenol yield. The extracts produced contained chlorogenic acid as the major constituent, accompanied by caffeic acid and minor amounts of p-coumaric acid. This is the first report on such an organosolv treatment of potato peels to recover polyphenolic compounds with high efficiency. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Graphical abstract

17 pages, 1403 KiB

Open AccessArticle

Proximate Analysis and Antioxidant Properties of Young Plants of Sinapis alba L. Depend on the Time of Harvest and Variety

by Urszula Sadowska, Klaudia Jewiarz, Magdalena Kopak, Kinga Dziadek, Renata Francik and Aneta Kopeć

Appl. Sci. 2023, 13(13), 7980; https://doi.org/10.3390/app13137980 - 07 Jul 2023

Cited by 5 | Viewed by 1120

Abstract

White mustard plant (Sinapis alba L.) is an easy-to-grow species with low soil requirements and is often sown as a catch crop in Northern Europe to reduce nitrate leaching, especially during the winter. There are studies showing the high nutritional value of mustard seeds, which have a wide application, mainly in food production. Still little is known about the young shoots or plants of different cultivars of white mustard, although in Asian countries, eating them raw is quite common. The aim of the research was to determine the proximate composition, antioxidant activity and polyphenolic compound content in young green plants of the Polish cultivars of white mustard: Borowska (traditional, with a high content of erucic acid and glucosinolates), Bamberka (non-erucic with glucosinolates) and Warta (non-erucic with low glucosinolates content; double-improved). Young plants were harvested in three terms. The first harvest took place at the plover stadium and the next ones at 7-day intervals (31, 38 and 45 day after sowing). In freeze-dried plant material, proximate composition and antioxidant activity with the ABTS and FRAP methods, as well as phenolic compound content, were measured. The highest concentration of protein was measured in cultivars Warta and Borowska after 31 and 38 days of sowing. Harvest time and cultivar affected antioxidant activity and total polyphenol content in young mustard plants. Thirty-eight days after sowing, the examined cultivars of the young plants of mustard had the highest antioxidant activity and total polyphenolic compound content. Green young mustard plants have strong antioxidant properties at the basic level, they are classified as functional foods and are similar to other edible leafy plants such as celery, spinach and Brussels sprouts. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

13 pages, 470 KiB

Open AccessArticle

Physico-Chemical Characteristics, Sensory Attributes and Oxidative Stability of Soy Milk Mayonnaise Enriched in Carotenoids from Tomato By-Products

by Ana Maria Blejan and Violeta Nour

Appl. Sci. 2023, 13(12), 7101; https://doi.org/10.3390/app13127101 - 14 Jun 2023

Cited by 2 | Viewed by 1107

Abstract

In the present study, sunflower oil was used as the extracting solvent for carotenoids and other lipophylic compounds from tomato by-products at 2.5% and 5.0% (w/v) and the carotenoid-enriched oils were further used in the manufacturing of soy milk mayonnaise. An addition of basil essential oil at 0.05% (v/v) in the carotenoid-enriched mayonnaise was also investigated. Color parameters, pH, acid, and peroxide values, as well as lipid oxidation as measured by TBARS values were monitored in control and in supplemented mayonnaise samples during refrigerated storage for up to 8 weeks. The effect of enrichment on the sensory attributes of mayonnaises was also studied. The extraction of dry tomato by-products resulted in a significant increase in the total carotenoid content and antioxidant activity of the oils while their color changed significantly by increasing the redness and decreasing the lightness and yellowness. The use of carotenoid-enriched oils in the mayonnaise manufacture increased the oxidative stability of soy milk mayonnaise during storage and improved the flavor and the chromatic characteristics of mayonnaise compared to the control sample without significantly affecting its consistency and overall acceptability. The addition of basil essential oil (0.05% v/v) enhanced the oxidative stability and improved the sensory profile of the mayonnaise. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

15 pages, 1890 KiB

Open AccessArticle

Antioxidant Capacity and Total Phenolic Content of Spice Extracts Obtained by Ultrasound-Assisted Extraction Using Deep Eutectic and Conventional Solvents

by Alicja Tymczewska, Julia Klebba and Aleksandra Szydłowska-Czerniak

Appl. Sci. 2023, 13(12), 6987; https://doi.org/10.3390/app13126987 - 09 Jun 2023

Cited by 4 | Viewed by 1251

Abstract

This study investigated the use of eco-friendly novel formulations of deep eutectic solvents (DESs) with water in ultrasound-assisted extraction (UAE) of antioxidant compounds from six spices, comparing them to traditional ethanol-based solvents. Significant differences in antioxidant capacity (AC) determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) assays, and total phenolic content (TPC) analysed using Folin-Ciocalteu (F-C) method were observed among the prepared extracts of spices. Regardless of the solvent used, clove extracts exhibited the highest antioxidant properties, whereas coriander presented the lowest values of AC and TPC. Choline chloride (ChCl)-based DES3 with propylene glycol (PG) as the hydrogen bond donor was more promising for effectively extracting antioxidants from the studied spices than ChCl-based DES1 and DES2 containing urea (U) and glycerol (Gly), respectively. Although DESs showed lower efficiency in this study, they represent a viable and environmentally sustainable approach for the extraction of bioactive compounds from spices. However, DES-based extracts can be recommended as potential sources of bioactive compounds and sustainable solvent systems for the plasticization and modification of active food packaging. This research offers valuable insights for the food, pharmaceutical, cosmetic, and spice industries, particularly for future developments in sustainable extraction techniques and potential applications in eco-friendly solutions and health-related areas. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

14 pages, 1279 KiB

Open AccessArticle

Effect of Black Cumin Cake Extract, Octyl Caffeate, and Active Packaging on Antioxidant Properties of Egg-Free Mayonnaise during Storage

by Katarzyna Włodarczyk, Alicja Tymczewska, Dobrochna Rabiej-Kozioł and Aleksandra Szydłowska-Czerniak

Appl. Sci. 2023, 13(10), 6245; https://doi.org/10.3390/app13106245 - 19 May 2023

Cited by 1 | Viewed by 847

Abstract

The egg-less mayonnaise (CM) based on aquafaba and refined rapeseed oil was prepared and enriched with black cumin cake extract (BCCE) at two concentrations of 0.1% (BCCM0.1%) and 3% (BCCM3%) and 0.1% of octyl caffeate (OCM). The obtained mayonnaises were placed in glass jars without and with active film incorporating BCCE at the jar bottom (AFM). The influence of antioxidants on oxidative stability and antioxidant capacity (AC) of the prepared mayonnaises was estimated by the shelf-life test. Peroxide value (PV), anisidine value (AnV), total oxidation (TOTOX) value, acid value (AV), and amounts of conjugated dienes (CD) and conjugated trienes (CT) were used to assess the extent of mayonnaise deterioration during storage of up to 4 weeks in a refrigerator. The synthesized octyl caffeate (OC) and natural antioxidants from BCCE added to mayonnaises directly and released from active film enhanced the AC of the studied mayonnaise samples determined using the QUick, Easy, New, CHEap, and Reproducible-2,2-diphenyl-1-picrylhydrazyl (QUENCHER-DPPH), and QUENCHER-2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (QUENCHER-ABTS) methods. All enriched mayonnaises had higher antioxidant potential than the AC of the control sample without antioxidants (CM) and commercial plant-based mayonnaise (CPBM). Therefore, the proposed antioxidants and active film can be used in the food industry to suppress lipid oxidation. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Graphical abstract

12 pages, 1049 KiB

Open AccessArticle

Nutritional, Antioxidant and Sensory Characteristics of Bread Enriched with Wholemeal Flour from Slovakian Black Oat Varieties

by Eva Ivanišová, Matej Čech, Peter Hozlár, Grzegorz Zaguła, Dorota Gumul, Olga Grygorieva, Agnieszka Makowska and Przemysław Łukasz Kowalczewski

Appl. Sci. 2023, 13(7), 4485; https://doi.org/10.3390/app13074485 - 01 Apr 2023

Cited by 2 | Viewed by 1327

Abstract

This paper is a report on the nutritional composition (dry matter, total protein, fat, crude fibre, ash, β-glucan content, and selected mineral compounds), antioxidant (antioxidant activity with the DPPH method and total anthocyanin content), physical properties, and sensory profiles of prepared bread enriched with black oat flours (variety Norik and Hucul) in amounts of 3, 6, and 9%. In the enriched breads (especially with 9% addition), there was a significantly higher (p < 0.05) content of protein (~13.00%), fat (~1.35%), crude fibre (~0.55%), ash (~1.25%), and β-glucan (~0.17%) with comparison to the control bread (12.01%; 0.87%; 0.47%; 0.92%; 0.07%, respectively). Among mineral compounds, the amount of manganese (~73.00 mg/100 g), iron (~45.00 mg/100 g), and calcium (~40.00 mg/100 g) were the highest in enriched breads with 9% of oat flours. In the case of antioxidant potential and total anthocyanin content, the same tendency was observed, and the values obtained were the highest in the case of 9% addition, especially with the Hucul variety (1.98 mg TEAC/g; 21.01 µg/g). The sensory properties of the prepared enriched breads were overall evaluated as good with the best score in smell, taste, colour, and properties of bread crumb (soft and flexible) compared to the control sample. Consumption of enriched breads with black oat can also increase the assortment of bakery products in markets, which is now popular for consumers. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

14 pages, 341 KiB

Open AccessFeature PaperArticle

Polyphenol Content, Mineral Compounds Composition, Antimicrobial and Antioxidant Activities of Selected Medicinal Herbs from Slovak Republic

by Eva Ivanišová, Marek Horňák, Matej Čech, Ľuboš Harangozo, Miroslava Kačániová, Olga Grygorieva and Przemysław Łukasz Kowalczewski

Appl. Sci. 2023, 13(3), 1918; https://doi.org/10.3390/app13031918 - 02 Feb 2023

Cited by 1 | Viewed by 1502

Abstract

The aim of this study was to determine antioxidant activity (DPPH and phosphomolybdenum method), polyphenols content (total polyphenols, flavonoids, and phenolic acids), mineral compounds composition (Cu, Zn, Mn, Fe, Cr, Ni, Co, Pb and Cd) and antimicrobial activity (with disc diffusion method) of medicinal herbs traditionally used in the Slovak republic. The tested plants belonged to the Primulaceae, Urticaceae, Grossulariaceae, Rosaceae, Lamiaceae, Asteraceae, Equisetaceae, Tropaeolaceae, and Plantaginaceae families. The highest antioxidant activities were found in samples of Rosa canina L. (DPPH—29.43 ± 0.11 mg TE/g; TE—Trolox equivalent) and Fragaria vesca L. (phosphomolybdenum method—679.56 ± 3.06 mg TE/g), both from the Rosaceae family. Total polyphenols (determined using the Folin–Ciocâlteu-reagent) were most abundant in a sample of Fragaria vesca L.—124.51 ± 5.05 mg GAE/g (GAE—gallic acid equivalent), total flavonoids (determined using the aluminum chloride method)—in a sample of Primula veris L.—48.35 ± 3.77 mg QE/g (QE—quercetin equivalent), and total phenolic acids (determined using Arnova reagent)—in a sample of Thymus serpyllum L.—102.31 ± 2.89 mg CAE/g (CAE—caffeic acid equivalent). Regarding mineral compounds composition, samples of Fragaria vesca L. and Thymus serpyllum L. showed the highest levels of iron. In samples of Calendula officinalis L. and Trapaeolum majus L., the highest amounts of zinc were determined, while copper was the most abundant in samples of Urtica dioica L. and Melissa officinalis L. The amounts of heavy metals were within legally acceptable limits. The extract of Equisetum arvense L. showed the strongest inhibitory activity towards Clostridium perfringens CCM 4991 (6 mm), while the one from Mentha piperita L.—towards Candida glabrata CCM 8270 (4.83 mm) and Candida tropicalis CCM 8223 (4.33 mm). Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

16 pages, 1767 KiB

Open AccessArticle

Antioxidant Properties of Selenium Nanoparticles Synthesized Using Tea and Herb Water Extracts

by Aleksandra Sentkowska and Krystyna Pyrzyńska

Appl. Sci. 2023, 13(2), 1071; https://doi.org/10.3390/app13021071 - 13 Jan 2023

Cited by 9 | Viewed by 2105

Abstract

Selenium nanoparticles (SeNPs) are the object of great interest due to their potential to be used in many areas of industry and medicine. Work is still underway on their synthesis methods; however, green methodologies are becoming more and more popular. In this study, aqueous extracts of black and green tea as well as infusions of popular herbs such as chamomile and mint were used in the synthesis of SeNPs serving as the Se(IV) reducers to its nano form. The influence of the reagents concentration ratios on the properties of the obtained nanoparticles were examined. SeNPs showed a greater ability to neutralize hydroxyl radicals compared to tea extracts. It has been proven that in the infusion of selenium-containing tea, the formation of SeNPs occurs. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

17 pages, 1798 KiB

Open AccessArticle

Ultrasound-Assisted Extraction of Specific Phenolic Compounds from Petroselinum crispum Leaves Using Response Surface Methodology and HPLC-PDA and Q-TOF-MS/MS Identification

by Afroditi Michalaki, Haralabos C. Karantonis, Anastasia S. Kritikou, Nikolaos S. Thomaidis and Marilena E. Dasenaki

Appl. Sci. 2023, 13(2), 798; https://doi.org/10.3390/app13020798 - 06 Jan 2023

Cited by 4 | Viewed by 1480

Abstract

Petroselinum crispum is native to the Mediterranean region and has been reported to contain several phenolic compounds in addition to the highest quantity of apigenin among several natural raw materials. The aim of the present study was to establish an extraction method for the most abundant phenolic compounds of Petroselinum crispum leaves by using response surface methodology. A Box–Behnken design was applied to optimize the extraction conditions with regards to the extraction time, temperature, solvent mixture, and sample to solvent ratio with the use of ultrasound-assisted extraction. An analytical HPLC-PDA methodology was developed to accurately quantify the phenolic compounds in the extracts. Identification of the most abundant phenolic compounds (luteolin, caffeic acid, and apigenin) was also performed with an UPLC-Q-TOF MS methodology. The predicted optimal conditions of the statistical model were identified, and the predicted values confirmed. Actual values of 23.92 ± 1.86 with 100 mL/g, 40% ethanol, 70 °C and 40 min, 19.10 ± 0.75 with 20 mL/g, 0% ethanol, 70 °C and 40 min, and 25.29 ± 1.82 μg/g dry parsley with and 100 mL/g, 0% ethanol, 25 °C and 40 min of luteolin, caffeic acid, and apigenin respectively, were estimated. Total phenolic content and antioxidant activities by DPPH, ABTS, FRAP, and CUPRAC assays were performed for the extracts. The extracts acquired under the optimum conditions contain an adequate quantity of phenolic compounds that could be used in the production of functional foods by food enrichment prcedure. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

14 pages, 1399 KiB

Open AccessFeature PaperArticle

Increasing the Oxidative Stability of the Wafer Lipid Fraction with Fruit Extract during Storage

by Liliana Bełkowska, Małgorzata Muzolf-Panek, Mahbuba Islam and Jolanta Tomaszewska-Gras

Appl. Sci. 2023, 13(1), 103; https://doi.org/10.3390/app13010103 - 21 Dec 2022

Viewed by 1074

Abstract

Confectionary products are increasingly popular among consumers. However, since they usually have a long shelf life (about 12 months), their oxidative stability during long-term storage becomes a significant issue. Thus, the aim of this study was to investigate the effect of addition of commercially available fruit extract on the oxidative stability of lipid fraction, extracted from wafers sheets stored 13 months at 18 °C. For this purpose, the oxidation induction times (OIT) were determined by using isothermal differential scanning calorimetry (DSC). Conjugated diene content (CD) and 2,2-diphenyl-1-pikrylhydrazyl (DPPH) antioxidant activity were also monitored. All results obtained showed that the fruit extract addition slowed down effectively the peroxidation process of lipid fraction of wafer sheets. The rate of OIT and CD changes during the first six months of storage were about two times lower for the sample with the extract (LWE) than for the control (LWS). The DPPH antioxidant activity of LWE was higher than for the LWS sample until the 8th month of storage. It was stated that fruit extract effectively enhanced the oxidative stability of lipid fraction of wafers up until the 10th month of storage. After this period, CD values increased significantly for LWS and LWE samples, while at the same time there were no significant differences in OIT and DPPH values between both samples (p > 0.05). Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

14 pages, 1119 KiB

Open AccessArticle

An Analysis of Commercial Noni Juice: LC-MS/MS Phenolic Profiles and Cytotoxic Activity

by Joel B. Johnson, Janice S. Mani and Mani Naiker

Appl. Sci. 2022, 12(24), 13034; https://doi.org/10.3390/app122413034 - 19 Dec 2022

Viewed by 2251

Abstract

Fermented juice from the noni tree (Morinda citrifolia) is a traditional medicinal product used by South Pacific Islanders to treat a wide range of ailments, including cancer, inflammation and obesity, as well as improving overall wellbeing. Many of its bioactive properties have been suggested to arise from the high antioxidant capacity and phenolic content found in the juice. However, there have been limited investigations into the phenolic profiles of noni juice produced locally in the Pacific. This study aimed to investigate the chemical composition and bioactive properties of noni juice. The first phase of this study used liquid chromatography with tandem mass spectrometry (LC-MS/MS) to characterise the phenolic composition of five brands of commercial noni juice produced in the South Pacific region. A total of 21 phenolic compounds were putatively identified, with the most abundant generally being rutin, 4-hydroxybenzoic acid and gentisic acid. Vastly differing phenolic profiles were found between the noni juice brands. Significant differences were also found in their antioxidant capacities and total phenolic contents. Of the three major phenolic compounds identified, gentisic acid showed the highest antioxidant activity (640% higher than Trolox). Additionally, the noni juice showed no significant anti-acetylcholinesterase activity and no to moderate cytotoxicity against two cancer cell lines (HeLa and HT29). These results indicate that the phytochemical profiles—and hence, the expected bioactive properties—are likely to vary significantly between different noni juice brands. Furthermore, the anti-cancer activity of non-concentrated noni juice appears to be relatively low. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

12 pages, 1565 KiB

Open AccessArticle

The Influence of Thiol Addition on Selenium Stability and Antioxidant Activity of Beetroot Juice

by Aleksandra Sentkowska and Krystyna Pyrzynska

Appl. Sci. 2022, 12(24), 12634; https://doi.org/10.3390/app122412634 - 09 Dec 2022

Cited by 2 | Viewed by 957

Abstract

Determination of selenium species in food samples causes problems due to their possible oxidation and degradation. In this study, the stability of selenium compounds present in beetroot juices after addition of recommended thiols, such as ditiotreitol (DDT) or β-mercaptoethanol (βME), was evaluated. More total selenium was found in homemade freshly squeezed beetroot juice than in that sold as an organic juice. Furthermore, Se(IV) and selenomethionine oxide (SeMetO) were the main Se species found in both juices. During storage at different temperatures, the concentrations of selenomethionine (SeMet) and Se-methylselenocysteine (MetSeCys) decreased, while Se(IV) and SeMetO contents increased. The addition of DDT or βME, regardless their concentration, did not increase the concentration of SeMet at the expense of SeMetO decrease, as it was expected based on the literature data. Moreover, the used thiols affected the quantification of other selenium species, particularly Se(IV). The purchased organic beetroot juice showed higher ability to scavenge free radicals when it was stored at 4 °C. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

12 pages, 689 KiB

Open AccessArticle

Relationship between Phenolic Compounds, Antioxidant Activity and Color Parameters of Red Table Grape Skins Using Linear Ordering Analysis

by Małgorzata Muzolf-Panek and Agnieszka Waśkiewicz

Appl. Sci. 2022, 12(12), 6146; https://doi.org/10.3390/app12126146 - 16 Jun 2022

Cited by 7 | Viewed by 1434

Abstract

Color, being one of the most important sensory characteristics, could be associated to the phenolic compound content and/or the antioxidant activity of fruits and vegetables. In this study, linear ordering was used to build quality rankings of red table grapes based on color parameters or phenolic compounds. First, the principle component analysis (PCA) was used to show the association between color of red grape skins (evaluated in CIE L*a*b* and L*C*h systems) and their individual phenolic compounds (investigated by the HPLC), total polyphenol content (TPC), total anthocyanins (ACNs), as well as the antioxidant activity (DPPH) of five table grape varieties. It could be observed that the lightness (L*) and hue angle (h) are the color coordinates strongly related to some phenolic compounds and ACN, whereas a* was related to DPPH and TPC. Five distinct clusters could be observed from PCA analysis with dark-colored grape varieties showing high levels of ACN (3.48–5.83 mg/g), low lightness (47.8–53.0), and high h values (353.7–359.8°). L*, a*, and h color coordinates were used to build table grape ranking. The second ranking was built based on phenolic compound content. Results of the two rankings were correlated. High Tau Kendall correlation coefficient (0.51, p = 0.000) indicated that linear ordering analysis, based on the simple color measurements, could be a useful tool for rapid screening of the quality of grapes. This could be valuable information for producers and consumers of the fruit making decision on the market. Full article

(This article belongs to the Special Issue New Insights into Natural Antioxidants in Foods)

► Show Figures

Figure 1

Journal Menu

Journal Browser

New Insights into Natural Antioxidants in Foods

Share This Special Issue

Special Issue Editor

Special Issue Information

Related Special Issue

Published Papers (14 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI