Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 650
Filtrar
1.
Anal Bioanal Chem ; 412(4): 933-948, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31927601

RESUMO

Deep eutectic solvents (DESs) were investigated as extracting solvent for headspace single-drop microextraction (HS-SDME). The extraction efficiency of 10 DESs mainly composed of tetrabutylammonium bromide (N4444Br) and long-chain alcohols was evaluated for the extraction of terpenes from six spices (cinnamon, cumin, fennel, clove, thyme, and nutmeg). The DES composed of N4444Br and dodecanol at a molar ratio of 1:2 showed the highest extraction efficiency and was selected to conduct the extractions of terpenes in the rest of the study. HS-SDME was optimized by design of experiments. Only two parameters from the four studied showed a significant influence on the efficiency of the method: the extraction time and the extraction temperature. The optimal extraction conditions were determined by response surface methodology. All extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). More than 40 terpenes were extracted and identified in nutmeg, the richest extract in terpenes in this study. Quantitative analysis based on 29 standards was conducted for each extract. Good linearity was obtained for all standards (R2 > 0.99) in the interval of 1 to 500 µg/g. Limits of quantification ranged from 0.47 µg/g (borneol) to 86.40 µg/g (α-farnesene) with more than half of the values under 2 µg/g. HS-SDME is simple, rapid, and cheap compared with conventional extraction methods. The use of DESs makes this extraction method "greener" and it was shown that DESs can be suitable solvents for the extraction of bioactive compounds from plants.


Assuntos
Microextração em Fase Líquida/métodos , Especiarias/análise , Terpenos/análise , Cinnamomum zeylanicum/química , Cuminum/química , Foeniculum/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Myristica/química , Extratos Vegetais/química , Solventes/química , Syzygium/química , Terpenos/isolamento & purificação , Thymus (Planta)/química
2.
Food Chem ; 307: 125521, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655264

RESUMO

The essential oils and antioxidant activity of four Thymus species were evaluated under five light spectra (namely, red, blue, red-blue, white, and greenhouse condition). The highest essential oil yield (4.17%) was observed under red light in T. migricus, while the lowest (1.05%) was observed in T. carmanicus under greenhouse conditions. Light quality also led to difference in essential oil constituents. The highest thymol (66%) was found in T. migricus exposed to blue light, while the least (1.69%) was observed in T. kotschyanus grown under red-blue light. The LED treatments did not induce any significant effect on carvacrol of Thymus species in comparison to the greenhouse condition. Finally, the analysis of variance indicates that the effect of light varied with the studied species. T. migricus performed the highest antioxidant capacity (IC50 = 176.8 µg/mL) under blue light. Overall, essential oil components as well as antioxidants showed significant responses to light emitting diodes wavelengths.


Assuntos
Antioxidantes/metabolismo , Luz , Timol/metabolismo , Thymus (Planta)/química , Análise de Variância , Antioxidantes/química , Cromatografia Gasosa , Análise por Conglomerados , Efeito Estufa , Óleos Voláteis/química , Análise de Componente Principal , Timol/química , Thymus (Planta)/crescimento & desenvolvimento , Thymus (Planta)/metabolismo
3.
J Sci Food Agric ; 100(2): 656-664, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31577841

RESUMO

BACKGROUND: The frozen preservation of lamb meat could be crucial for successful international trade. The shelf life of thawed meat is shorter than that of fresh meat, so techniques or procedures are required to improve post-thawing meat quality attributes. This study investigated the effect of alginate-based edible coatings after the incorporation of essential oils of thyme (Thymus vulgaris L.) and garlic (Allium sativum L.) on thawed lamb meat (longissimus thoracis et lumborum muscle) quality after long-term frozen storage. Meat samples came from ten light lambs and the evolution of attributes related to shelf life, such as water-holding capacity, color stability, and lipid oxidation, was monitored during display (1, 4 and 7 days). Four meat treatments were evaluated: control (CON, uncoated meat), edible coat of alginate meat (ECA), and ECA with thyme or garlic essential oils (0.05%) (THY and GAR). RESULTS: The alginate-based edible coatings decreased exudative losses (P < 0.001) and modified color characteristics, especially increasing yellowness (P < 0.001) and chrome (P < 0.001). GAR decreased redness (P < 0.001) and the oxy/met ratio [R (630/580) wavelength light reflectance] or discoloration [R (630-580)]. THY was the treatment that best retained color during display and also showed a significantly lower lipid oxidation (P < 0.05) than CON and ECA, whereas GAR presented intermediate values. CONCLUSION: The addition of bioactive essential oils to alginate-based edible coatings improved preservation and shelf life of lamb meat after thawing. © 2019 Society of Chemical Industry.


Assuntos
Conservação de Alimentos/métodos , Conservantes de Alimentos/análise , Alho/química , Carne/análise , Óleos Voláteis/análise , Extratos Vegetais/análise , Thymus (Planta)/química , Animais , Armazenamento de Alimentos , Lipídeos/química , Oxirredução , Ovinos
4.
Food Microbiol ; 86: 103357, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703857

RESUMO

We investigated combinations of gaseous essential oils (EO gases) for their synergistic inhibitory activities against Listeria monocytogenes on a laboratory medium and radish sprouts. The minimum inhibitory concentrations and minimum lethal concentrations of oregano, thyme thymol, and cinnamon bark EO gases against L. monocytogenes were 0.0781 µL/mL on nutrient agar supplemented with glucose and bromocresol purple (NGBA). A checkerboard assay showed that combinations of oregano and thyme thymol EO gases and of oregano and cinnamon bark EO gases exert the strongest synergistic antilisterial activity (fractional inhibitory concentration index [FICI] = 0.3750). A combination of thyme thymol and cinnamon bark EO gases also had a synergistic effect (FICI = 0.5000) on L. monocytogenes on NGBA. Combinations of oregano and thyme thymol EO gases were tested for synergistic antimicrobial activity against L. monocytogenes on radish sprouts. A combination of these gases, each at 0.313 µL/mL, caused a significant (P ≤ 0.05) reduction in the number of L. monocytogenes on radish sprouts compared with reductions caused by treatment with oregano or thyme thymol EO gas alone at the same concentration. Our findings provide information that will be useful when developing antimicrobial applications using EO gases to control L. monocytogenes in the food industry.


Assuntos
Antibacterianos/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Óleos Voláteis/farmacologia , Origanum/química , Raphanus/microbiologia , Timol/farmacologia , Thymus (Planta)/química , Antibacterianos/química , Cinnamomum zeylanicum/química , Meios de Cultura/química , Meios de Cultura/metabolismo , Sinergismo Farmacológico , Gases/farmacologia , Listeria monocytogenes/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Vegetais/química , Óleos Vegetais/farmacologia , Raphanus/crescimento & desenvolvimento , Timol/química
5.
Food Microbiol ; 86: 103338, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703867

RESUMO

Tahini is a popular food product in the Middle East region and is used as a major ingredient in several ready-to-eat food products. Tahini and its products have been linked to foodborne illness outbreaks and product recalls worldwide as a result of Salmonella spp. contamination. The objectives of the current study were to investigate: i) the effectiveness of 10 plant essential oil extracts on the viability of Salmonella spp. using disc diffusion ii) the antimicrobial activity of the most effective oils against Salmonella spp. in commercial or 10% w/v hydrated tahini (tahini-based product model) stored at 37, 25 and 10 °C for 28 d and iii) the effect of the addition of essential oil extracts on the sensory acceptability of tahini and hydrated tahini. Among the tested essential oils, thyme (TO) and cinnamon oil (CO) showed the highest antimicrobial activity against tested Salmonella spp. at 37 and 10 °C using a disc diffusion assay method. In tahini, the addition of 2.0% CO reduced the numbers of Salmonella spp. by 2.87, 2.64 or 2.35 log10 CFU/ml at 37, 25 or 10 °C, respectively, by 28 d. However, the antimicrobial activity of CO was more pronounced at all storage temperatures in hydrated tahini where no viable cells were detected after 3 d storage at 25 and 37 °C, or after 7 d at 10 °C. However, at 25 and 37 °C, the antimicrobial activity of CO was more evident since no viable cells were detected after 14 d when 0.5% was used. The numbers of Salmonella spp. were reduced by 3.29, 3.03 or 2.17 log10 CFU/ml at 37, 25 or 10 °C, respectively, after 28 d when 2.0% TO was added to tahini. Salmonella spp. were not detected in the hydrated tahini treated with 2.0% TO after 28 d at 37 °C or 25 °C, while at 10 °C, the numbers of Salmonella spp. were not significantly reduced after 28 d in hydrated tahini compared to the initial numbers at zero time. Therefore, the addition of TO and CO could be used to preclude the post process contamination of tahini with foodborne pathogens, yet, the addition of TO and CO to tahini reduced its consumer acceptability compared untreated tahini.


Assuntos
Cinnamomum zeylanicum/química , Aditivos Alimentares/farmacologia , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Salmonella/efeitos dos fármacos , Sesamum/microbiologia , Thymus (Planta)/química , Humanos , Salmonella/crescimento & desenvolvimento , Paladar , Temperatura Ambiente
6.
J Food Sci ; 84(11): 3147-3155, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31599978

RESUMO

Oxidative stability of hempseed and soybean oils, was evaluated after heating at 180 °C, followed by a subsequent 14-day storage at 38 °C. Natural plant extracts (Rosemary, Sage, and Thyme) were added to oils, to evaluate the carry-over stabilizing potential. Heated oils exhibited a relatively faster (P < 0.05) onset of lipid oxidation, as depicted by the analysis of the peroxides and aldehydes formed during the lipid oxidation process, with hempseed oil being more susceptible to lipid oxidation than soybean oil. There were notable losses in ω-3 PUFA and ω-6-GLA during storage of heat treated hempseed oil (P < 0.05). Moreover, peroxide values measured from hempseed oil remained low after high-temperature heating but progressed at a relatively greater rate than that observed in soybean during storage (P < 0.05). The addition of different plant extracts to oils did not prevent oxidation due to heating, but effectively inhibited the generation of hydroperoxides during subsequent storage (P < 0.05). This stabilizing effect was attributed to retention of tocopherols, in particular, γ-tocopherol. PRACTICAL APPLICATION: This research demonstrates the use of plant extracts like rosemary, sage and thyme, for improving the shelf-life and nutritional stability of hempseed and soybean oil. We demonstrate the deterioration of fatty acid profiles and vitamin E levels in the oil on heating and subsequent storage, and show the efficacy of using plant extracts in slowing down these deteriorations. This research will be applicable in food industries using or producing oils for use in food during cooking, and also as dressing on already processed food products.


Assuntos
Cannabis/química , Ácidos Graxos Ômega-3/análise , Manipulação de Alimentos/métodos , Extratos Vegetais/farmacologia , Óleo de Soja/química , Vitamina E/análise , Ácidos Graxos/análise , Armazenamento de Alimentos/métodos , Temperatura Alta , Peróxido de Hidrogênio/análise , Peroxidação de Lipídeos/efeitos dos fármacos , Óleos Vegetais/química , Rosmarinus/química , Salvia officinalis/química , Sementes/química , Thymus (Planta)/química
7.
Molecules ; 24(17)2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31455036

RESUMO

Thymus marschallianus Willd. is a Lamiaceae species spread in a large variety of habitats worldwide. The aim of the present research was to analyse two different samples belonging to this species, one obtained from the spontaneous flora and one from culture. The total polyphenols, flavonoids, and phenolic acid contents were spectrophotometrically determined. Qualitative and quantitative analysis of polyphenols was performed by an HPLC-DAD-ESI (+)-MS method. For the antibacterial assay, the well-diffusion and the broth microdilution methods were used. Analysis of polyphenols revealed for both samples the presence of flavonoids like luteolin, quercetin, apigenin and their derivatives, but also of rosmarinic acid and methyl-rosmarinate. Differences regarding the amount of these compounds were emphasized. Significantly larger amounts of flavonoids were found for the sample harvested in the spontaneous flora, while for the rosmarinic acid, larger amounts were found for the cultured sample. Both samples displayed promising antibacterial activity, particularly towards Gram positive organisms. T. marschallianus represents, therefore, a rich source of polyphenolic compounds that prove its promising potential as a medicinal species.


Assuntos
Anti-Infecciosos/farmacologia , Compostos Fitoquímicos/farmacologia , Thymus (Planta)/química , Anti-Infecciosos/química , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Flavonoides/química , Flavonoides/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Hidroxibenzoatos/química , Hidroxibenzoatos/farmacologia , Compostos Fitoquímicos/química , Polifenóis/química , Polifenóis/farmacologia
8.
Environ Sci Pollut Res Int ; 26(30): 30885-30892, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31446593

RESUMO

The western flower thrips (Frankliniella occidentalis Perg.) is one of the most economically important insect pests of greenhouse plants. Plant protection against this pest is based predominantly on synthetic insecticides; however, this form of protection poses problems in terms of thrip resistance to the active substances, along with health risks associated with insecticide residues on the treated plants. Therefore, new active substances need to be sought. Essential oils could be a new, appropriate, and safe alternative for greenhouse culture protection. As greenhouses are enclosed areas, fumigation application of EOs is possible. This paper presents acute toxicity results for 15 commercial EOs applied by fumigation, as well as the effect of sublethal concentrations on fertility of F. occidentalis females. The most efficient EOs were obtained from Mentha pulegium and Thymus mastichina, with LC50(90) estimated as 3.1(3.8) and 3.6 (4.6) mg L-1 air, respectively. As found for the very first time, sublethal concentrations of EOs could result in a significant reduction in the fertility of surviving T. occidentalis females. Among the tested EOs, the EO from Nepeta cataria provided the highest inhibition of fertility, with EC50(90) estimated as 0.18 (0.36) mg L-1 air. Chemical composition of the most efficient EOs and possible applications of the results in practice are discussed. In conclusion, in light of the newly determined facts, EOs can be recommended as active substances for botanical insecticides to be applied against Thysanopteran pests by fumigation.


Assuntos
Inseticidas/farmacologia , Óleos Voláteis/farmacologia , Tisanópteros/efeitos dos fármacos , Animais , Feminino , Fertilidade/efeitos dos fármacos , Fumigação , Mentha pulegium/química , Óleos Voláteis/química , Thymus (Planta)/química , Tisanópteros/fisiologia
9.
J Food Sci ; 84(9): 2467-2474, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31449337

RESUMO

The antioxidant stability of minced pork treated with thyme and oregano essential oils (EOs) was determined. Minced pork containing different concentrations (0%, 0.3%, 0.6%, or 0.9%) of thyme (TEO) or oregano essential oil (OEO) and packaged under vacuum or modified atmosphere (MAP) (30%O2 /50%CO2 /20%N2 ) was evaluated within 15 days of refrigeration (3 ± 1 °C) storage. EOs were examined for scavenging capacity toward 2,2-diphenyl-1-picrylhydrazyl, nitric oxide radicals, and hydroxyl, and inhibition of lipid peroxidation and ferric ion reducing antioxidant power (butylated hydroxytoluene was used as positive controls). The order of antioxidative effectiveness was as follows: butylated hydroxytoluene > OEO > TEO, with significant differences between agents (P < 0.05). Lipid oxidation in meat was determined by monitoring malondialdehyde (MDA) formation and lipolysis was assessed by measuring the acidity index immediately and after 3, 6, 9, 12, and 15 days of storage. EOs significantly (P < 0.05) increased the stability of minced pork with respect to lipid oxidation compared with the control, and the antioxidative effect was dose-dependent. Moreover, vacuum packaging resulted in mince with significantly lower oxidation and lipolysis levels than modified atmosphere packaged mince (P < 0.05). The results demonstrate that both EOs examined effectively reduced lipid oxidation in raw pork mince after 2 weeks' storage. PRACTICAL APPLICATION: The natural food preservatives market is growing rapidly, as is high demand for organic foods. These results are likely to be of interest to the scientists, researchers, and persons who work in the meat industry. Results and discussion can contribute to a better understanding of antioxidative properties of essential oils in food model. Furthermore, no study has reported the effect of these MAP on pork oxidative stability.


Assuntos
Antioxidantes/química , Conservação de Alimentos/métodos , Conservantes de Alimentos/química , Carne/análise , Óleos Voláteis/química , Origanum/química , Extratos Vegetais/química , Thymus (Planta)/química , Animais , Embalagem de Alimentos , Oxirredução , Refrigeração , Suínos , Vácuo
10.
Food Chem Toxicol ; 133: 110747, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377137

RESUMO

Three autochthonous flavouring herbs from Alentejo (Portugal), Calamintha nepeta (syn. Clinopodium nepeta), Origanun virens and Thymus mastichina, were selected to evaluate toxicological, antioxidant, antiproliferative and antimicrobial potential of their essential oils (EOs). C. nepeta and T. mastichina EOs showed a high content of oxygenated monoterpenes (86-91%) while O. virens had similar content of oxygenated and hydrocarbon monoterpenes (45%). Toxicological assessment suggests high activity against A. salina (31.8 < CL50 < 128.4 mg/L) and very low toxicity in Swiss mice (DL50 ≥ 1500 mg/kg). EOs showed high antioxidant ability by DPPH radical scavenging assay (0.1-0.6 mg QE/mL EO), total reducing power method (0.2-1.7 mg QE/mL EO) and ß-carotene/linoleic acid system (11-501 mg QE/mL EO). An important antiproliferative effect against human breast tumour cell line was observed (88.9 < EC50 < 108.5 mg/L). Moreover, EOs presented a large antibacterial spectrum. Results point out the low toxicity and high antioxidant, antiproliferative and antimicrobial activities of EOs of these endemic aromatic plants, suggesting their potential use in biotechnological, food and/or pharmaceutical industries.


Assuntos
Óleos Voláteis/farmacologia , Óleos Voláteis/toxicidade , Óleos Vegetais/farmacologia , Óleos Vegetais/toxicidade , Animais , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Antineoplásicos/farmacologia , Antineoplásicos/toxicidade , Antioxidantes/farmacologia , Antioxidantes/toxicidade , Artemia/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Nepeta/química , Origanum/química , Portugal , Thymus (Planta)/química
11.
Planta Med ; 85(11-12): 941-946, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31163460

RESUMO

Targeted isolation based on a combination of NMR and HPLC-PDA-MS of a dichloromethane extract of Thymus vulgaris Varico 3 aerial parts afforded one new p-cymene dimer, 6,3',4'-trihydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (1: ), together with two known p-cymene derivatives (2: and 3: ), as well as five known compounds, namely, thymol (4: ), oleanolic acid (5: ), ursolic acid (6: ), cirsimaritin (7: ), and xanthomicrol (8: ). The structural elucidation of all compounds was performed by spectroscopic analyses, including 1D and 2D NMR, and HRESIMS experiments. The biphenyls were assayed for their inhibitory activity on tyrosinase. Compounds 2: and 3: showed negligible activity on tyrosinase, while compound 1: effectively inhibited the enzyme with 35% (± 0.3) inhibitory activity, higher than the inhibition of the reference compound kojic acid (18.6 ± 0.02).


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectroscopia de Ressonância Magnética/métodos , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monoterpenos/isolamento & purificação , Extratos Vegetais/química , Thymus (Planta)/química , Flavonas/farmacologia , Monoterpenos/farmacologia , Ácido Oleanólico/farmacologia , Timol/farmacologia , Triterpenos/farmacologia
12.
Int J Food Microbiol ; 305: 108246, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31238193

RESUMO

Cellulosic pads, amended with emulsions containing essential oils of thyme and oregano, exhibited antimicrobial activity against the psychrophilic microbiota of minced beef. In addition, the pads were active against specific meat bacterial species (Pseudomonas putida, Pseudomonas fragi, Pseudomonas fluorescens, Enterococcus faecalis and Lactococcus lactis) and some common foodborne pathogens (Salmonella enterica, Campylobacter jejuni and Staphylococcus aureus). Three emulsions, IT131017, Mediterranean and Etnic, containing different percentages of carvacrol, thymol, linalool, and ɑ and ß-pinene, significantly reduced the growth of S. enterica and P. putida. Pads derived from emulsions Mediterranean and Etnic induced slight (0.3-0.8 Log10 CFUs/g) but reproducible reduction of the psychrophilic microbiota in minced meat and hamburger stored for 12 and 15 days at 4 °C.


Assuntos
Antibacterianos/farmacologia , Cinnamomum zeylanicum/química , Óleos Voláteis/farmacologia , Origanum/química , Extratos Vegetais/farmacologia , Carne Vermelha/microbiologia , Thymus (Planta)/química , Animais , Antibacterianos/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Compostos Bicíclicos com Pontes , Bovinos , Celulose/química , Emulsões/química , Emulsões/farmacologia , Microbiologia de Alimentos , Carne/microbiologia , Monoterpenos/química , Monoterpenos/farmacologia , Óleos Voláteis/química , Extratos Vegetais/química , Carne Vermelha/análise , Timol/química , Timol/farmacologia
13.
Br Poult Sci ; 60(5): 589-596, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195808

RESUMO

1. The purpose of this study was to examine if the concentration of thymol as the main compound of Thymus vulgaris essential oil (TEO) influenced the antioxidant defence system in broilers. 2. Twenty-four broiler chickens were randomly divided at the day of hatching into three dietary treatment groups (0%, 0.05% and 0.1%, w/w TEO) with eight birds in each and were fed until four weeks of age. 3. Thymol content in plasma, duodenal wall and breast muscle significantly increased when 0.1% of thyme oil was added to the diet (P < 0.05). Thymol concentration in plasma significantly correlated with levels measured in the duodenal wall and feed (rs = 0.7857, P < 0.05; rs = 0.7647, P < 0.05). Superoxide dismutase (SOD) activity increased, and malondialdehyde (MDA) concentration decreased significantly (P < 0.05) in blood from chickens fed 0.1% TEO supplementation. Although the thymol concentration did not significantly decrease MDA amounts in breast muscle, a declining trend was observed. 4. The trial data confirmed the efficient absorption of thymol from the digestive tract into the systemic circulation, but only traces were found in breast muscle. Thymol content was sufficient for expressing its antioxidant properties in blood, but its low content in breast muscle was insufficient to significantly affect lipid oxidation and fatty acid composition.


Assuntos
Antioxidantes/fisiologia , Galinhas/imunologia , Gorduras Insaturadas na Dieta/metabolismo , Óleos Voláteis/metabolismo , Timol/metabolismo , Thymus (Planta)/química , Ração Animal/análise , Animais , Galinhas/metabolismo , Dieta/veterinária , Gorduras Insaturadas na Dieta/administração & dosagem , Suplementos Nutricionais , Óleos Voláteis/administração & dosagem , Óleos Voláteis/análise , Timol/administração & dosagem , Timol/análise
14.
Food Microbiol ; 83: 9-17, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31202423

RESUMO

The aims of this study were (i) screening of antifungal activity of thyme essential oil on Penicillium paneum; (ii) development of growth/no-growth models (G/NG); and (iii) validation of the G/NG models by performing bread baking trials. The screening method was based on the measurement of fungal growth in a semi-solid medium through optical density. The combined influence of aw (0.88-0.97), pH (4.8-7.0), temperature (22 and 30 °C), time (0-144 h) and varying concentrations of thyme oil (0-2 µL/mL YES) were assessed. Growth of P. paneum at aw 0.88 was significantly reduced compared to aw 0.93-0.97. A slight pH effect was observed at aw 0.93; growth was delayed at pH 6 compared to pH 4.8. The lowest concentration of thyme oil preventing growth during 144 h of incubation was 1 µL/mL medium. According to the results of the shelf-life test of par-baked bread, fungal growth was inhibited for more than 45 days using 0.3 mL thyme oil/100 g dough. To conclude, this study recognized the potential of using G/NG models to develop better product formulations and to facilitate product innovation.


Assuntos
Antifúngicos/farmacologia , Óleos Voláteis/farmacologia , Penicillium/efeitos dos fármacos , Penicillium/crescimento & desenvolvimento , Temperatura Ambiente , Thymus (Planta)/química , Pão/microbiologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Água
15.
BMC Complement Altern Med ; 19(1): 146, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227024

RESUMO

BACKGROUND: There is increasing interest in the pharmaceutical and food industries to substitute synthetic chemicals with naturally occurring compounds possessing bioactive properties. Plants are valuable sources of bioactive compounds. The present study investigates the chemical composition and antioxidant, antimicrobial, and anticancer activities of ethanolic extracts (EEs) and essential oils (EOs) from two species in the Lamiaceae family, Ocimum basilicum L. and Thymus algeriensis Boiss. & Reut., cultivated in the Algerian Saharan Atlas. METHODS: The total flavonoid contents of the plants' ethanolic extracts were determined by the aluminium chloride method, while the total phenols were determined using the Folin-Ciocalteu method. Essential oils were obtained by hydrodistillation of the aerial parts of the plants and were analysed by GC-MS. The free radical-scavenging ability and antioxidant potential of the plants' EEs and EOs were probed using the 2, 2-diphenyl-picrylhydrazyl radical-scavenging, ABTS radical-scavenging, ferric-reducing power and phosphomolybdenum assays. The antimicrobial activities were evaluated against several pathogens characteristic of gram-negative bacteria (three species), gram-positive bacteria (three species) and fungi (two species). The microdilution method was used to estimate the minimum inhibitory concentrations (MICs). The oils' anticancer potential against several cancer types was also studied using the MTT assay and reported as the toxic doses that resulted in a 50% reduction in cancer cell growth (LD50). RESULTS: Phenolic compounds in the EEs from both plants were analysed by HPLC and demonstrated a rich flavonoid content. Chemical analysis of the essential oil from Ocimum basilicum revealed 26 unique compounds, with linalool (52.1%) and linalyl acetate (19.1%) as the major compounds. A total of 29 compounds were identified in the essential oil from Thymus algeriensis, with α-terpinyl acetate (47.4%), neryl acetate (9.6%), and α-pinene (6.8%) as the major compounds. The ethanolic extracts and essential oils from both plants exhibited moderate antioxidant activities and moderate to weak antimicrobial activities. Furthermore, anticancer activities against the examined human cancer cell lines were associated with only the EOs from both plants, with LD50 values ranging between 300 and 1000 µg/mL. CONCLUSION: The results suggest that the bioactive compounds found in the ethanolic extracts and essential oils from Ocimum basilicum and Thymus algeriensis, with diverse antioxidant, antimicrobial and anticancer activities, may have beneficial applications in nutraceutical and pharmaceutical technologies.


Assuntos
Ocimum basilicum/química , Óleos Voláteis/química , Óleos Vegetais/química , Thymus (Planta)/química , Argélia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Linhagem Celular Tumoral , Sobrevivência Celular , Cromatografia Líquida de Alta Pressão , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Fenol/química , Fenol/farmacologia , Óleos Vegetais/farmacologia
16.
J Food Sci ; 84(6): 1427-1438, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31070787

RESUMO

Thyme essential oil-loaded microcapsules (TMS) were fabricated using natural polysaccharide chitosan (CS) and sodium alginate (SA) as the shell material via the method of layer-by-layer (LBL) assembly. The accumulated release rates of thyme oil and microcapsules at 4 °C were 42.50% and 10.16%, respectively. After heating at 100 °C for 5 hr, the release rate of the 0, 2, 4, 6 layers assembled microcapsules were 100%, 48.84%, 28.38%, 19.3%, severally. Microcapsules also had good pH sensitivity in the range of 4 to 10. Antimicrobial function studies showed that the microcapsules are more effective than thyme oil for three tested microorganisms. When the temperature rose from 37 °C to 121 °C, the antibacterial zone of thyme oil gradually decreased from 18.5 ± 0.6 mm to 12.3 ± 0.6 mm, although inhibition rate of microcapsules increased from 87.97% to 99.75%. The antibacterial effect of thyme oil declined with the increase of pH, in terms of microcapsules, the efficiency was better under acidic or alkaline conditions. The thyme oil microcapsules can suppress the growth of Staphylococcus aureus in milk and prolong its shelf life. It was determined that this microcapsule could be a potential alternative as a natural antimicrobial agent in food and pharmaceutical industries. PRACTICAL APPLICATION: This work provided release performance and mechanism of layer-by-layer (LBL) thyme oil microcapsule under different conditions, and further studies showed its antibacterial ability to explore how herb essential oils can be potentially applied in food packaging and antibacterial areas.


Assuntos
Óleos Vegetais , Thymus (Planta)/química , Alginatos/química , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Cápsulas/química , Cápsulas/farmacologia , Quitosana/química , Preparações de Ação Retardada , Concentração de Íons de Hidrogênio , Leite/microbiologia , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Temperatura Ambiente
17.
J Food Sci ; 84(6): 1439-1446, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31106862

RESUMO

The fumigant toxicity of eight individual essential oils (EOs; basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree, and thyme) and one binary combination (thyme and oregano) for control of the rice weevil, Sitophilus oryzae, were investigated. In bioassays, all individual and combined EOs were toxic to the rice weevil. Eucalyptus EO exhibited the highest toxicity among the individual EO treatments, causing 100% mortality at a minimum concentration of 0.8 µL/mL after 24 hr of exposure. The combination treatment of oregano and thyme EO displayed higher fumigant activity than the individual oregano or thyme treatments. A stable oil-in-water nanoemulsion was evaluated using high-pressure homogenization (microfluidization [MF]) and varying the pressure and number of cycles. The droplet size of the emulsions was found to decrease from 217 to 71 nm and encapsulation efficiency increased from 37% to 84% with increasing MF pressure and number of cycles. The optimum conditions for preparing the mixture of oregano and thyme EO nanoemulsions were evaluated to be homogenization pressure of 103 MPa and three cycles. Incorporating an oregano:thyme nanoemulsion (0.75%) into cellulose nanocrystal (CNC) containing chitosan (CH/CNC), methyl cellulose (MC/CNC), and polylactic acid (PLA/CNC) composite films resulted in extended diffusion matrices causing 32% to 51% rice weevil mortality after 14 days exposure. Irradiation at 200 Gray alone caused 79% mortality and increased to 100% when combined with the bioactive chitosan film containing the oregano:thyme nanoemulsion. PRACTICAL APPLICATION: A binary combination of oregano:thyme has potential as a biopesticide against stored product pests. The encapsulation of EO nanoemulsions into biopolymeric support could be used for bioactive packaging to prevent food spoilage and extend shelf life. Combining bioactive films with irradiation can provide complete control of rice weevil in packaged rice. The system developed in this research may also be extended to explore other food-packaging films with various food models to control different types of stored pests.


Assuntos
Irradiação de Alimentos , Embalagem de Alimentos/instrumentação , Armazenamento de Alimentos/métodos , Nanocompostos , Óleos Voláteis/farmacologia , Gorgulhos/efeitos dos fármacos , Animais , Agentes de Controle Biológico , Biopolímeros/química , Quitosana , Cinnamomum zeylanicum , Grão Comestível , Emulsões , Óleo de Eucalipto/farmacologia , Embalagem de Alimentos/métodos , Fumigação , Origanum/química , Controle de Pragas/métodos , Radiação Ionizante , Thymus (Planta)/química , Gorgulhos/efeitos da radiação
18.
J Anim Sci ; 97(7): 2901-2913, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31119279

RESUMO

The thyme (Thymus vulgaris) essential oil was assessed as antibiotic growth promoter replacement in quail chick diet and in vitro test. In total, 250-d-old Japanese quail chicks (mixed sex) were allocated into 5 dietary treatments of 5 replications (6 females and 4 males in each cage with the size of 40× 90× 25 cm) under a completely randomized design. The dietary treatments were included the control diet, control diet without any additive, control diet plus 100 ppm flavophospholipol as an antibiotic growth promoter, control diet plus 200 ppm TVE, control diet plus 300 ppm TVE, and control diet plus 400 ppm T. vulgaris essential (TVE) oil. Feed intake, BW gain, feed conversion ratio (FCR), organs weight, morphology of intestine, serum lipids, and microbial population were measured on day 35. Lipid oxidation of stored muscle tissue was measured by TBARS test. GC-MS assay, DPPH method, and well diffusion method were evaluated for determination of components, antioxidant, and antimicrobial properties, respectively. FCR improved significantly in 400 ppm TVE compared with 200 and 300 ppm TVE (P < 0.05). The serum triglyceride decreased significantly in both sexes receiving 400 ppm TVE compared with control. Villi height increased significantly in duodenum accompanied by decreasing crypt dept at all TVE levels compared with control and antibiotic. The breast muscle tissue of quail fed on 300 and 400 ppm TVE reduced the rate of oxidation during refrigerated storage compared with control. Thymol was the main component (35.40%) of the thymus oil. The considerable antioxidant activity of TVE was identified by IC50 of 58.48 µg/mL. Moreover, zones of growth inhibition of Gram-positive bacteria and Escherichia coli were numerically greater in different doses of TVE than antibiotics. Therefore, The TVE is suitable alternative component for antibiotic growth promoters by dosing consideration. However, it is possible that antibiotic resistance would increase for these natural compounds along the time.


Assuntos
Antioxidantes/metabolismo , Coturnix/fisiologia , Suplementos Nutricionais/análise , Óleos Voláteis/farmacologia , Óleos Vegetais/farmacologia , Thymus (Planta)/química , Ração Animal/análise , Animais , Antibacterianos/farmacologia , Dieta/veterinária , Feminino , Intestinos/efeitos dos fármacos , Intestinos/microbiologia , Masculino , Distribuição Aleatória , Timol/metabolismo
19.
Molecules ; 24(10)2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31117281

RESUMO

Candida biofilm structure is particularly difficult to eradicate, since biofilm is much more resistant to antifungal agents than planktonic cells. In this context, a more effective strategy seems to be the prevention of biofilm formation than its eradication. The aim of the study was to examine whether the process of initial colonization of materials (glass, polyethylene terephthalate, polypropylene) by food-borne Candida sp. can be impeded by clove and thyme essential oils, used at their minimal inhibitory concentrations. In the presence of clove oil, 68.4-84.2% of the yeast tested showed a statistically significant reduction in biofilm formation, depending on the material. After treatment with thyme oil, statistically significant decrease in biofilm cell numbers was observed for 63.2-73.7% of yeasts. Confocal laser scanning microscopy showed diverse compounds of clove and thyme oils that were disparately located in C. albicans cell, on a cell wall and a cell membrane, in cytoplasm, and in vacuoles, depicting the multidirectional action of essential oils. However, essential oils that were used in sub-inhibitory concentration were sequestrated in the yeast vacuoles, which indicate the activation of Candida defense mechanisms by cell detoxification. Clove and thyme essential oils due to their anti-biofilm activity can be efficiently used in the prevention of the tested abiotic surfaces colonization by Candida sp.


Assuntos
Biofilmes/efeitos dos fármacos , Óleos Voláteis/farmacologia , Syzygium/química , Thymus (Planta)/química , Antifúngicos/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/patogenicidade , Parede Celular/efeitos dos fármacos , Óleo de Cravo/química , Óleo de Cravo/farmacologia , Testes de Sensibilidade Microbiana , Óleos Voláteis/química , Óleos Vegetais/química , Óleos Vegetais/farmacologia
20.
Food Sci Technol Int ; 25(7): 579-587, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31117823

RESUMO

The objective of this work was to evaluate the effects of different decontamination treatments on the quality of dehydrated thyme, coriander, and mustard. Treatments applied were: (i) ultraviolet radiation treatment irradiation; (ii) steam, (iii) steam-ultraviolet radiation treatment; (iv) humidification-ultraviolet radiation treatment, and (v) steam-humidification-ultraviolet radiation treatment. Their effectiveness to control indigenous aerobic mesophiles and yeasts and molds population was assessed by plate count. The effect of proposed treatments on total polyphenol contents and antioxidant activity was also evaluated. Furthermore, the effect of treatments on spices performance to prevent canola oil oxidation was also analyzed. The use of steam-ultraviolet radiation treatment in aqueous medium was the most effective for decontamination, reducing the aerobic mesophiles and yeasts and molds counts between 1.0 and 2.2 log CFU/g dry spice. This treatment decreased significantly the polyphenol content and the antioxidant capacity of the three spices analyzed. However, in the case of mustard, the residual antioxidant compounds were able to control canola oil oxidation more efficiently than butylated hydroxytoluene. Results suggest that the use of steam-ultraviolet radiation treatment in aqueous medium can be useful in food preservation processes.


Assuntos
Coriandrum/química , Descontaminação/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Mostardeira/química , Thymus (Planta)/química , Antioxidantes/análise , Dessecação , Manipulação de Alimentos , Oxirredução , Polifenóis/análise , Óleo de Brassica napus , Especiarias/análise , Vapor , Raios Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA