جستجوی مقالات مرتبط با کلیدواژه "antioxidant effect" در نشریات گروه "صنایع غذایی"

Chemical properties and antimicrobial effect of Thymus trautvetteri essential oil against some of the bacteria causing infection and food poisoning were evaluated in this study. For this purpose, T. trautvetteri essential oil was extracted with the help of hydrodistillation method and its total phenol content was based on Folin-Ciocalteu method, its antioxidant activity was based on DPPH and ABTS free radical inhibition methods and its antibacterial effect against Escherichia coli, Shigella dysenteriae, Staphylococcus aureus and Bacillus cereus were investigated based on disc diffusion agar, well diffusion agar, minimum inhibitory concentration and minimum bactericidal concentration methods. The results showed that T. trautvetteri essential oil contained 6.27 mg of catechin/g total phenol and its inhibitory activity against DPPH and ABTS free radicals was obtained as 12.32 and 10.20 mg/ml, respectively. The results of the antibacterial activity of the essential oil showed that S. aureus and E. coli were the most sensitive and resistant bacterial strains against T. trautvetteri essential oil, respectively. The inhibition zone in the disc diffusion agar and well diffusion agar methods, and the minimum inhibitory and bactericidal concentrations for S. aureus were 14.60 mm, 16 mm, 1 mg/ml and 4 mg/ml, respectively. According to the findings of this research, T. trautvetteri essential oil can be used as a natural antioxidant and antimicrobial agent to prevent oxidative reactions and microbial spoilage in food.

Grape is a very perishable fruit that has a short shelf life. Due to the increase in consumer awareness, the tendency to use natural preservative compounds instead of pesticides and chemical preservatives has increased. Plant essential oils are considered to be the most appropriate natural compounds due to their potentially effective compounds. Therefore, the aim of this research was to identify the chemical compounds of Foeniculum vulgare essential oil, determine its phenolic and flavonoid content, and investigate the antioxidant and antifungal activity of this essential oil against a number of molds that cause spoilage after grape fruit harvesting. The compounds identified in F. vulgare essential oil included limonene, fenchone, p-allylanisole and anethole, which made up 97.60% of the total essential oil. The total phenol content of F. vulgare essential oil was equal to 26.29 mg GAE/g and the total flavonoid content was equal to 19.23 mg QE/g. The antioxidant properties of the essential oil of this plant were obtained by DPPH, ABTS and beta-carotene-linoleic acid decolorization methods, respectively, 38.56, 42.12, and 30.30%. Also, , it was found that Foeniculum vulgare essential oil is capable of inhibiting and controlling Rhizopus stolonifera, Aspergillus niger, and Botrytis cinerea. Due to the antimicrobial and antioxidant compounds present in F. vulgare, the essential oil of this plant can be used as a compound with practical properties to increase the shelf life of agricultural products, including grapes.

In the present study, the hydroalcoholic extract of Withania somnifera was extracted and then the content of total phenol (by Folin-Ciocalteu reagent), total flavonoid (by aluminum chloride method), antioxidant activity (based on DPPH and ABTS free radical scavenging methods) and its antifungal effect against Rhizopu stolonifers, Botrytis cinerea, Penicillium expansum and Alternaria alternata (fungi cause spoilage postharvest apple and strawberry fruits) were determined based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration. The amount of phenol and flavonoids in the extract was 53.16 mg GAE/g and 28.20 mg QE/g, respectively. The antioxidant power of the hydroalcoholic extract was 69.80 and 57.15 μg/ml in terms of DPPH and ABTS free radical scavenging, respectively. The results of antimicrobial activity based on disk diffusion agar and well diffusion agar showed that increasing the concentration of the extract caused a significant increase in the diameter of the growth inhibition zone and Botrytis cinerea and Alternaria alternata were the most resistant and sensitive strains to the extract, respectively. In general, Penicillium expansum and Alternaria alternata were more sensitive than Rhizopus stolonifer and Botrytis cinerea with minimum inhibitory and fungicidal concentrations of 16 and 128 mg/ml, respectively.

Oxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties.

β-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS  radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration.

The results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms.

Economic losses can occur due to the growth of fungi on foods that lead to food spoilage and plant diseases. Fruits and vegetables are often exposed to microbial activity, caused by pathogenic fungi, during post-harvest storage. Diseases of food origin are a growing public health problem. Thus, food safety has become a major public concern as microbial contamination increases the risk of foodborne illnesses and shortens the shelf life of foods. Infection with fungi such as Aspergillus, Rhizopus, and Penicillium species is considered as the primary cause of rapid spoilage of fresh produce, which reduces their quality and shelf life. Synthetic fungicides have been applied to solve this problem for many years. Nonetheless, the adverse effects of synthetic chemicals on human health and the emergence of fungicide-resistant strains have motivated the scientists and food industries to find out safe preservatives to control postharvest rot/diseases. On this point, natural antimicrobial agents such as plant extracts and essential oils are gaining more and more interest. In this study, we used Levisticum officinale Koch essential oil, which its antimicrobial and antioxidant activity has been reported in literatures. 

L. officinale Koch essential oil was obtained by hydrodistillation method and its total phenol content, total flavonoids, antioxidant activity (based on DPPH and ABTS free radical scavenging and β-carotene bleaching tests) and its antifungal effect against fungi causing apple and orange rotting (Alternaria alternata, Penicillium expansum, Penicillium digitatum, Penicillium italicum, and Botrytis cinerea) were examined according to antimicrobial tests of disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration. 

L. officinale Koch essential oil contained 61.27 ± 0.34 mg GAE/g and 20.14 ± 0.21 mg QE/g total phenol and flavonoids, respectively. Its antioxidant activity, based on DPPH free radical scavenging, ABTS free radical scavenging, and β-carotene bleaching inhibition were 69.72 ± 0.65%, 78.54 ± 0.3% and 57.50 ± 0.41%, respectively. L. officinale Koch essential oil was effective against all fungal species and the highest susceptibility was observed for Penicillium expansum. According to the results, L. officinale Koch essential oil can be used as a natural antifungal agent to prevent post-harvest diseases of fruits and vegetables.

The aim of this study was to isolate ethanolic extract from Urtica dioica leaves, and determination of its antioxidant and antimicrobial properties. On this point, the ethanolic extract was obtained by the maceration method and its total phenol content, total flavonoid content, antioxidant activity (DPPH and ABTS radical scavenging activity) and antimicrobial effect (disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) against Salmonella typhi, Escherichia coli, Bacillus cereus, and Listeria innocua, were determined. The extract contained 65.42 ± 0.49 mg GAE/g total phenol content and 22.19 ± 0.30 mg QE/g total flavonoid content. The ethanolic extract of U. dioica leaves was able to scavenge DPPH (61.90 ± 0.54%) and ABTS (70.10 ± 0.47%) free radicals. The antimicrobial effect results showed that Gram-positive bacteria (Bacillus cereus and Listeria innocua) were more sensitive than Gram-negative ones (Salmonella typhi and Escherichia coli) toward the ethanolic extract. Generally, U. dioica leaves’ ethanolic extract is able to be used as a natural bioactive compound to improve shelf-life of food products.

In the present study, the hydroalcoholic extract of Seidlitzia rosmarinus was obtained using maceration method and its antifungal effect against fungi species causing orange fruit rot (Penicillium digitatum and Penicillium italicum) according to disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration were evaluated. In addition, the content of total phenols and flavonoids and the antioxidant activity of the hydroalcoholic extract of S. rosmarinus were determined. According to the results of disk diffusion and well diffusion agar tests, the antifungal activity of the extract was dependent on its concentration and P. digitatum was the most sensitive fungal strain to the extract. Moreover, both fungal strains were unable to grow in the presence of 32 mg/ml extract and the minimum fungicidal concentration for P. digitatum was 512 mg/ml. The contents of total phenols and total flavonoids of the extract were 26.19 mg GAE/g and 11.10 mg QE/g, respectively. The results of antioxidant activity showed that the hydroalcoholic extract of S. rosmarinus is able to scavenge DPPH (112.14 μg/ml) and ABTS (103.46 μg/ml) free radicals. In general, the results of this study show that the hydroalcoholic extract of S. rosmarinus plant contains phenolic compounds with antifungal and antioxidant potential.

This study investigated the total phenols and flavonoids content, antioxidant potential (based on DPPH and ABTS free radical scavenging methods), and antibacterial mechanism (based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) of ethanolic extract of Mentha aquatica. The extract contained significant levels of bioactive phenolic compounds (total phenol: 88.47 ± 0.32 mg gallic acid per gram of extract; total flavonoids: 39.15 ± 0.25 mg quercetin per gram of extract) with acceptable ability in scavenging DPPH (58.50 ± 0.57%) and ABTS (51.44 ± 0.32%) free radicals. The growth of pathogenic and spoilage bacteria, especially Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) in comparison with Gram-negative pairs (Escherichia coli and Salmonella enteritidis) was strongly inhibited by the plant extract. In general, Staphylococcus aureus and Salmonella enteritidis were the most sensitive and resistant microbial strains to the ethanolic extract of M. aquatica, respectively. The present study showed that the ethanolic extract of M. aquatica with significant antioxidant and antimicrobial properties can be used to develop new natural preservatives for food and medicinal purposes.

In recent years, special attention has been devoted to plant-derived drugs. Herbal medicines contain versatile compounds with a vast range of therapeutic effects. In this study, methanolic extract of Rumex alveollatus L. was obtained thorough the maceration method, and its total phenol content, total flavonoid content, antioxidant activity (DPPH and ABTS radical scavenging methods) and antimicrobial property (disk diffusion agar, well diffusion agar, and minimum inhibitory/bactericidal concentration) against Enterobacter aerogenes, Staphylococcus aureus, Salmonella typhi, and Streptococcus pyogenes were evaluated. The methanolic extract of Rumex alveollatus contained 91.90 mg gallic acid/g total phenols and 48.60 mg quercetin/g total flavonoids. Antioxidant activity results showed that the extract was able to scavenge DPPH (69.58%) and ABTS (80.59%) free radicals. The growth of microorganisms was inhibited in the presence of high concentrations of the extract, and E. aerogenes and S. aureus were the most resistant and sensitive bacterial species to the methanolic extract of Rumex alveollatus. Therefore, Rumex alveollatus methanolic extract could be introduced as an effective compound in controlling bacterial infections and oxidation of lipid-based compounds.