Microbiology
Ali Ehsani; Omar Alizadeh; Mohammad Hashemi; Asma Afshari; Majid Aminzare
Volume 8, Issue 3 , September 2017, , Pages 223-229
Abstract
Aromatic plants are rich in essential oils with considerable antimicrobial properties.The aim of this study was to investigate chemical composition, antimicrobial activity and antioxidant properties of Melissa officinalis and Deracocephalum moldavica essential oils (EOs). The identification of chemical ...
Read More
Aromatic plants are rich in essential oils with considerable antimicrobial properties.The aim of this study was to investigate chemical composition, antimicrobial activity and antioxidant properties of Melissa officinalis and Deracocephalum moldavica essential oils (EOs). The identification of chemical constituents of the EOs was carried out using gas chromato-graphy-mass spectrometry analysis and antimicrobial activity of the EOs was evaluated by disc diffusion assay as well as determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration against four important food-borne bacteria: Salmonella typhimorium, Escherichia coli, Listeria monocytogenes and Staphylococcus aureus. Antioxidant activity of the EOs was also determined by 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis 3-ethylbenzo thiazoline-6-sulfonic acid and β-carotene bleaching tests. The major compounds of D. moldavica were geranial (28.52%), neral (21.21%), geraniol (19.60%), geranyl acetate (16.72%) and the major compounds of M. officinalis EO were citronellal (37.33%), thymol (11.96%), citral (10.10%) and β-caryophyllene (7.27%). The underlying results indicated strong antimicrobial effects of the oils against tested bacteria. Staphylococcus aureus with the lowest MIC value (0.12 mg mL-1) for both EOs was the most sensitive bacterium, although, antibacterial effect of M. officinalis EO was stronger than D. moldavica. In addition, the results of the antioxidant activity showed that both EOs had notable antioxidant properties. In conclusion, both EOs are appropriate alternatives as potential sources of natural preservative agents with the aim of being applied in food industries.
Food Hygiene
Ali Ehsani; Mohammad Hashemi; Nima Hosseini Jazani; Javad Aliakbarlu; Sajad Shokri; Seyedeh Samane Naghibi
Volume 7, Issue 2 , June 2016, , Pages 139-148
Abstract
The present study was carried out to enhance shelf life of pasteurized cream using Echinophora platyloba essential oil (EEO) and lycopene. For this purpose, two concentrations of EEO (0.10% and 0.50%) and lycopene (20 and 50 ppm) alone and together as combinations were added in pasteurized creams and ...
Read More
The present study was carried out to enhance shelf life of pasteurized cream using Echinophora platyloba essential oil (EEO) and lycopene. For this purpose, two concentrations of EEO (0.10% and 0.50%) and lycopene (20 and 50 ppm) alone and together as combinations were added in pasteurized creams and analyzed for microbial characteristics, sensorial properties and lipid stability during storage at 4 ˚C and 25 ˚C for 14 days. Results of microbial and chemical analyses of experimental pasteurized creams showed that pasteurized creams treated with combinations of the EEO and lycopene in their higher concentrations had the best microbial and chemical properties and the most stability than control during storage (p < 0.05). Results of sensorial evaluation demonstrated that all treatments had favorable overall acceptability, even though, the best sensorial properties were observed in creams with combinations of EEO and lycopene in their lower concentrations. Therefore, based on the results of the present study, application of EEO and lycopene as natural preservatives is especially recommend in high fat dairy products such as butter and cream.
Abdollah Jamshidi; Saeid Khanzadi; Majid Azizi; Mohammad Azizzadeh; Mohammad Hashemi
Volume 5, Issue 2 , June 2014, , Pages 107-114
Abstract
Black zira (Bunium persicum) is a medicinal plant and spice, naturally grows in Iran. The aim of this study was to investigate the combined effects of different concentrations of Bunium persicum essential oil (EO; including 0, 0.08, 0.16 and 0.24%), three incubation temperatures (15, 25 and 35˚C), three ...
Read More
Black zira (Bunium persicum) is a medicinal plant and spice, naturally grows in Iran. The aim of this study was to investigate the combined effects of different concentrations of Bunium persicum essential oil (EO; including 0, 0.08, 0.16 and 0.24%), three incubation temperatures (15, 25 and 35˚C), three levels of pH (5, 6 and 7 adjusted by hydrochloric acid), and three inoculum size (102, 103 and 104 CFU mL-1) on the growth of Staphylococcus aureus in the brain heart infusion broth. Black zira EO was extracted and its component was identified using gas chromatography-mass spectrometry (GC-MS) analyses. The experiment was carried out in triplicate. Growth was monitored by visible turbidity during a 30-day period. To evaluate effects of explanatory variable on time to detection (TTD) of bacterial growth, parametric survival models based on Log-normal distribution was used. All explanatory variables had significant association with time to detection (p < 0.05). The final model accurately predicted the growth initiation and inhibition of S. aureus.
Mohammad Hashemi; Ali Ehsani; Nima Hosseini Jazani; Javad Aliakbarlu; Razzaqh Mahmoudi
Volume 4, Issue 2 , June 2013, , Pages 123-127
Abstract
Echinophora Platyloba D.C as a medicinal plant is used for preservation of foods and treatment of many diseases in different regions of Iran. The present study was undertaken to determine the chemical composition and investigation of the antibacterial effects of essential oil as well as methanol extract ...
Read More
Echinophora Platyloba D.C as a medicinal plant is used for preservation of foods and treatment of many diseases in different regions of Iran. The present study was undertaken to determine the chemical composition and investigation of the antibacterial effects of essential oil as well as methanol extract from aerial part of Echinophora Platyloba D.C against S. aureus, L. monocytogenes, S. Thyphimurium and E. coli. Chemical analysis using gas chromatography and mass spectrophotometry (GC/MS) showed that ocimene (26.51%), 2,3-Dimethyl-cyclohexa-1,3-diene (9.87%), alpha-pinene (7.69%) and gamma-dodecanolactone (5.66%) were dominant components of essential oil and the main constituents of methanol extract were o-Cymene (28.66%), methanol (8.50%), alpha-pinene (7.42%) and gamma-decalactone (5.20%). The essential oil showed strong antimicrobial activity against tested bacteria, whereas the methanol extract almost remained inactive against gram-negative bacteria. The most sensitive bacteria to essential oil and extract of Echinophora Platyloba D.C were L. monocytogenes and S. aureus. Minimum inhibitory concentration (MIC) values of essential oil against L. monocytogenes and S. aureus were 6250 and 12500 ppm, respectively. MIC of methanol extract against S. aureus and L. monocytogenes was 25000 ppm. Therefore, purifying and evaluation of antibacterial effects of the active substances of the essential oil and methanol extract of this plant for future application as antibacterial agents and food preservatives to combat pathogenic and toxigenic microorganisms is recommended.