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17 pages, 1403 KiB

Open AccessArticle

In Silico and In Vitro Evaluation of the Antimicrobial and Antioxidant Potential of Mentha × smithiana R. GRAHAM Essential Oil from Western Romania

by Călin Jianu, Daniela Stoin, Ileana Cocan, Ioan David, Georgeta Pop, Alexandra Teodora Lukinich-Gruia, Marius Mioc, Alexandra Mioc, Codruța Șoica, Delia Muntean, Laura-Cristina Rusu, Ionuț Goleț and Delia Ioana Horhat

Foods 2021, 10(4), 815; https://doi.org/10.3390/foods10040815 - 9 Apr 2021

Cited by 23 | Viewed by 2621

Abstract

This study was conducted to identify the volatile compounds of Mentha × smithiana essential oil (MSEO) and evaluate its antioxidant and antibacterial potential. The essential oil (EO) content was assessed by gas chromatography–mass spectrometry (GC-MS). Carvone (55.71%), limonene (18.83%), trans-carveol (3.54%), cis [...] Read more.

This study was conducted to identify the volatile compounds of Mentha × smithiana essential oil (MSEO) and evaluate its antioxidant and antibacterial potential. The essential oil (EO) content was assessed by gas chromatography–mass spectrometry (GC-MS). Carvone (55.71%), limonene (18.83%), trans-carveol (3.54%), cis-carveol (2.72%), beta-bourbonene (1.94%), and caryophyllene oxide (1.59%) were the main identified compounds. The MSEO displayed broad-spectrum antibacterial effects and was also found to be the most effective antifungal agent against Candida albicans and Candida parapsilosis. The antioxidant activity of MSEO was tested against cold-pressed sunflower oil by peroxide, thiobarbituric acid, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), and β-carotene/linoleic acid bleaching methods. The EO showed strong antioxidant effects as reflected by IC₅₀ values of 0.83 ± 0.01 mg/mL and relative antioxidative activity of 87.32 ± 0.03% in DPPH and β-carotene/linoleic acid bleaching assays, respectively. Moreover, in the first 8 days of the incubation period, the inhibition of primary and secondary oxidation compounds induced by the MSEO (0.3 mg/mL) was significantly stronger (p < 0.05) than that of butylated hydroxyanisole. In silico molecular docking studies were conducted to highlight the underlying antimicrobial mechanism as well as the in vitro antioxidant potential. Recorded data showed that the antimicrobial activity of MSEO compounds could be exerted through the D-Alanine-d-alanine ligase (DDl) inhibition and may be attributed to a cumulative effect. The most active compounds are minor components of the MSEO. Docking results also revealed that several mint EO components could exert their in vitro antioxidant activity by employing xanthine oxidase inhibition. Consequently, MSEO could be a new natural source of antioxidants and antiseptics, with potential applications in the food and pharmaceutical industries as an alternative to the utilization of synthetic additives. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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14 pages, 1348 KiB

Open AccessArticle

Antioxidant Properties of Pecan Shell Bioactive Components of Different Cultivars and Extraction Methods

by Cameron Cason, Veerachandra K. Yemmireddy, Juan Moreira and Achyut Adhikari

Foods 2021, 10(4), 713; https://doi.org/10.3390/foods10040713 - 27 Mar 2021

Cited by 7 | Viewed by 2501

Abstract

Pecan shells are a rich source of various bioactive compounds with potential antioxidant and antimicrobial properties. This study investigated the effect of pecan variety and method extraction on the antioxidant property of shell extracts. Twenty different varieties of pecan shells were subjected to [...] Read more.

Pecan shells are a rich source of various bioactive compounds with potential antioxidant and antimicrobial properties. This study investigated the effect of pecan variety and method extraction on the antioxidant property of shell extracts. Twenty different varieties of pecan shells were subjected to either aqueous or ethanolic extraction and were examined for total phenolics and antiradical activity. The phenolic content and antiradical activity of shell extracts were significantly (p < 0.05) varied with different pecan cultivars. The total phenolic content of ethanol extracts ranged from 304.2 (Caddo) to 153.54 (Cherokee) mg GAE g⁻¹ of dry extract and was significantly greater (p < 0.05) than those obtained by aqueous extraction. The antiradical activity of ethanol extracts ranged from 840.6 (Maramec) to 526.74 (Caper Fear) mg TE g⁻¹, while aqueous extracts ranged from 934.9 (Curtis) to 468.3 (Elliot) mg TE g⁻¹. Chemical profiling of the crude and acid hydrolyzed extracts was performed by reverse phase high performance liquid chromatography and flow injection electrospray ionization mass spectrometry. Lignin degradation products such as lignols, dilignols, trilignols, and oligolignols were found to be the major components of tested extracts. Phenolic content and antiradical activity of pecan shell extracts are significantly varied with cultivars and methods of extraction. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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12 pages, 1895 KiB

Open AccessArticle

Antimicrobial Activity and Chemical Characterization of a Non-Polar Extract of Saffron Stamens in Food Matrix

by Severino Zara, Giacomo L. Petretto, Alberto Mannu, Giacomo Zara, Marilena Budroni, Ilaria Mannazzu, Chiara Multineddu, Giorgio Pintore and Francesco Fancello

Foods 2021, 10(4), 703; https://doi.org/10.3390/foods10040703 - 26 Mar 2021

Cited by 18 | Viewed by 3102

Abstract

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar [...] Read more.

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar fraction extracted from four different saffron flower stamens. The chemical composition of ethereal extracts of the saffron stamens was qualitatively assessed by means of gas–chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses. These analyses revealed ethereal extracts to possess a high polyunsaturated fatty acid content. In vitro antibacterial activity of stamen extracts showed no large differences between Gram-positive and Gram-negative bacteria in terms of minimal inhibitory concentration (MIC). In food matrix microbial analysis of the bacterial strains belonging to the main foodborne pathogen species, including Staphylococcus aureus DSM 20231, Escherichia coli DSM 30083, and Listeria monocytogenes DSM 20600, using low-fat UHT milk, revealed a statistically significant reduction in the number of cells (particularly for E. coli and S. aureus with a complete elimination of the population of the two target bacteria following incubation in diethyl ether extracts of saffron stamen (DES) at high concentrations tested, both at 37 °C and 6 °C (for 48 h and 7 days, respectively). A synergic effect was observed when the pathogens were incubated at 6 °C with DES. This work shows these by-products to be excellent sources of bioactive compounds, which could be exploited in high-added-value products, such as food, cosmetics, and drugs. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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11 pages, 1911 KiB

Open AccessArticle

Evaluation of Recombinant Kpkt Cytotoxicity on HaCaT Cells: Further Steps towards the Biotechnological Exploitation Yeast Killer Toxins

by Gavino Carboni, Ivana Marova, Giacomo Zara, Severino Zara, Marilena Budroni and Ilaria Mannazzu

Foods 2021, 10(3), 556; https://doi.org/10.3390/foods10030556 - 8 Mar 2021

Cited by 7 | Viewed by 2022

Abstract

The soil yeast Tetrapisispora phaffii secretes a killer toxin, named Kpkt, that shows β-glucanase activity and is lethal to wine spoilage yeasts belonging to Kloeckera/Hanseniaspora, Saccharomycodes and Zygosaccharomyces. When expressed in Komagataella phaffii, recombinant Kpkt displays a wider spectrum of [...] Read more.

The soil yeast Tetrapisispora phaffii secretes a killer toxin, named Kpkt, that shows β-glucanase activity and is lethal to wine spoilage yeasts belonging to Kloeckera/Hanseniaspora, Saccharomycodes and Zygosaccharomyces. When expressed in Komagataella phaffii, recombinant Kpkt displays a wider spectrum of action as compared to its native counterpart, being active on a vast array of wine yeasts and food-related bacteria. Here, to gather information on recombinant Kpkt cytotoxicity, lyophilized preparations of this toxin (LrKpkt) were obtained and tested on immortalized human keratinocyte HaCaT cells, a model for the stratified squamous epithelium of the oral cavity and esophagus. LrKpkt proved harmless to HaCaT cells at concentrations up to 36 AU/mL, which are largely above those required to kill food-related yeasts and bacteria in vitro (0.25–2 AU/mL). At higher concentrations, it showed a dose dependent effect that was comparable to that of the negative control and therefore could be ascribed to compounds, other than the toxin, occurring in the lyophilized preparations. Considering the dearth of studies regarding the effects of yeast killer toxins on human cell lines, these results represent a first mandatory step towards the evaluation the possible risks associated to human intake. Moreover, in accordance with that observed on Ceratitis capitata and Musca domestica, they support the lack of toxicity of this toxin on non-target eukaryotic models and corroborate the possible exploitation of killer toxins as natural antimicrobials in the food and beverages industries. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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15 pages, 325 KiB

Open AccessArticle

Nutritional and Antioxidant Potential of Fiddleheads from European Ferns

by Marcela Dvorakova, Karolína Pumprova, Žaneta Antonínová, Jan Rezek, Daniel Haisel, Libor Ekrt, Tomas Vanek and Lenka Langhansova

Foods 2021, 10(2), 460; https://doi.org/10.3390/foods10020460 - 19 Feb 2021

Cited by 18 | Viewed by 4903

Abstract

Ferns are part of the diet and traditional medicine in East Asia, North America, and Oceania, however, their importance has been forgotten in Europe. Here, the nutritional and antioxidant potential of young fern fronds (fiddleheads) of eight families were studied. Most of the [...] Read more.

Ferns are part of the diet and traditional medicine in East Asia, North America, and Oceania, however, their importance has been forgotten in Europe. Here, the nutritional and antioxidant potential of young fern fronds (fiddleheads) of eight families were studied. Most of the tested fern species excelled in high antioxidant capacity when compared to the reference leafy vegetables spinach and rocket. On average, the total phenol content reached 220 mg·g⁻¹ of extract dry weight for all fiddleheads, and 15 out of 24 tested species exceeded 1 g Trolox equivalent per gram of extract dry weight in Oxygen Radical Absorbance Capacity (ORAC) assay. On the other hand, fiddleheads contained a comparable amount of carotenoids and ascorbic acid with the reference vegetables. In the case of fatty acid composition, fiddleheads contained especially high amounts of essential omega-3 (n3) and omega-6 (n6) polyunsaturated fatty acids with a beneficial n6/n3 ratio. The n6/n3 ratio in all tested species was between 2 and 6.4, whereas the ratio in the reference vegetables was below 0.4. All in all, fiddleheads from European ferns are a rich source of valuable antioxidants and essential fatty acids with a desirable n-6/n-3 ratio and may thus form an alternative source of these compounds, especially for those people not consuming fish and fish products. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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12 pages, 927 KiB

Open AccessArticle

Application of White Mustard Bran and Flour on Bread as Natural Preservative Agents

by Raquel Torrijos, Tiago de Melo Nazareth, Juan Manuel Quiles, Jordi Mañes and Giuseppe Meca

Foods 2021, 10(2), 431; https://doi.org/10.3390/foods10020431 - 16 Feb 2021

Cited by 10 | Viewed by 3120

Abstract

In this study, the antifungal activity of white mustard bran (MB), a by-product of mustard (Sinapis alba) milling, and white mustard seed flour (MF) was tested against mycotoxigenic fungi in the agar diffusion method. The results obtained were posteriorly confirmed in [...] Read more.

In this study, the antifungal activity of white mustard bran (MB), a by-product of mustard (Sinapis alba) milling, and white mustard seed flour (MF) was tested against mycotoxigenic fungi in the agar diffusion method. The results obtained were posteriorly confirmed in a quantitative test, determining the minimum concentration of extract that inhibits the fungal growth (MIC) and the minimum concentration with fungicidal activity (MFC). Since MF demonstrated no antifungal activity, the MB was stored under different temperature conditions and storage time to determine its antifungal stability. Finally, an in situ assay was carried out, applying the MB as a natural ingredient into the dough to avoid P. commune CECT 20767 growth and increase the bread shelf life. The results demonstrated that the antifungal activity of MB was dose-dependent. The higher assayed dose of MB (10 g/kg) reduced the fungal population in 4.20 Log CFU/g regarding the control group. Moreover, the shelf life was extended four days compared to the control, equaling its effectiveness with the synthetic preservative sodium propionate (E-281). Therefore, MB could be an alternative to chemical additives in bread formulations since it satisfies consumer requirements. Also, the formulation of bread with MB valorizes this by-product generated during mustard seed milling, thereby helping the industry move forward sustainably by reducing environmental impact. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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19 pages, 2095 KiB

Open AccessArticle

Development and Characterization of a Nutritionally Rich Spray-Dried Honey Powder

by Yogita Suhag, Gulzar Ahmad Nayik, Ioannis K. Karabagias and Vikas Nanda

Foods 2021, 10(1), 162; https://doi.org/10.3390/foods10010162 - 14 Jan 2021

Cited by 21 | Viewed by 5137

Abstract

In the present study, the spray-dried honey powder enriched with aonla (Emblica officinalis Gaertn) and basil (Ocimum sanctum) extract was developed using drying aids—gum arabic (GA), maltodextrin (MD), and whey protein concentrate (WPC), and then characterized based on particle size [...] Read more.

In the present study, the spray-dried honey powder enriched with aonla (Emblica officinalis Gaertn) and basil (Ocimum sanctum) extract was developed using drying aids—gum arabic (GA), maltodextrin (MD), and whey protein concentrate (WPC), and then characterized based on particle size distribution, colour, glass transition temperature (Tg), X-ray diffraction, and antioxidant and rheological properties. Results showed the highest Tg (86.13 °C) for WPC based honey powder, which, in turn, resulted in least stickiness as compared to GA and MD based honey powders with Tg 74.53 °C and 68.26 °C, respectively. The dried honey powder with all three carrier agents exhibited a metastable amorphous state as proved by the broader peaks of X-ray diffractograms due to the short drying time, whereas, a peak at 1637 cm⁻¹, attributed to the carbonyl (C=O) stretching, established the ascorbic acid in the studied powder on account of aonla extract. The mean particle diameter significantly (p < 0.05) increased, following the order WPC (60.45 μm) > GA (41.24 μm) > MD (20.06 μm) as carrier agents, which were related to the higher feed viscosity. The colour parameter L* (30.74–45.78) and b* (5.82–11.64) values of the nutritionally rich honey powder were higher due to presence of polyphenols in aonla and basil extracts, which resulted in the formation of dark brown complexes. The antioxidant activity of WPC based fortified honey powder was highest (82.73%), followed by GA (78.15%) and MD (74.85%) based honey powders. A significant (p < 0.05) increase was found in powder recovery, solubility, and dispersibility using the drying aids in the following order: WPC < GA < MD. Furthermore, the storage modulus (G′) was higher than loss modulus (G″) in all honey powders, wherein the WPC containing powder demonstrated maximum value of G′, followed by GA and MD. Finally, the three honey powders were microbiologically stable. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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16 pages, 1982 KiB

Open AccessArticle

Packaging Design Using Mustard Seeds as a Natural Antimicrobial: A Study on Inhibition of Pseudomonas fragi in Liquid Medium

by Nur Alim Bahmid, Jenneke Heising, Vincenzo Fogliano and Matthijs Dekker

Foods 2020, 9(6), 789; https://doi.org/10.3390/foods9060789 - 16 Jun 2020

Cited by 12 | Viewed by 5949

Abstract

Pseudomonas fragi is the dominant spoilage organism in various foods, especially in spoiled milk, fish, and meats. Its growth can be inhibited by releasing allyl isothiocyanate (AITC) from ground mustard seeds in food packages. This paper aims to investigate the antimicrobial potential of [...] Read more.

Pseudomonas fragi is the dominant spoilage organism in various foods, especially in spoiled milk, fish, and meats. Its growth can be inhibited by releasing allyl isothiocyanate (AITC) from ground mustard seeds in food packages. This paper aims to investigate the antimicrobial potential of ground mustard seeds against P. fragi growth and the effectiveness of released AITC concentration from mustard seeds on microbial inhibition of the spoilage bacteria growing in the liquid medium. The AITC concentration in the headspace and the liquid medium was measured and the growth of P. fragi in the liquid medium was monitored. Depending on the concentration of AITC, not only growth was inhibited but a reduction of the total count of P. fragi was even observed. The inactivation rate (k) of P. fragi was estimated using first-order inactivation kinetics and the minimum gaseous-released AITC to inactivate P. fragi was determined. Higher AITC concentration in the headspace and liquid medium was observed when using a higher amount of ground mustard seeds and a lower food to headspace ratio. Increasing the amount of ground mustard seeds (>100 mg per 10 mL liquid medium) led to full inactivation of P. fragi in 48 hours. By using an inhibition sigmoid E_max model, the minimum gaseous-released AITC for inactivation of P. fragi in 48 hours was observed around 15 µg/L headspace. These results indicate that inhibition of the spoilage bacteria and extending the shelf life using ground mustard seeds is only possible by applying a careful design of the packaging system. Full article

(This article belongs to the Special Issue Natural Compounds as Novel Sources of Antimicrobial and Antioxidative Agents in Food)

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