Search

The phytochemical and biological properties of tangerine ( Citrus reticulata L.), grapefruit ( Citrus paradisi L.), lemon ( Citrus lemon L.) and cinnamon ( Cinnamomum zeylanicum Blume) essential oils were examined. The chemical composition of the essential oils determined using chromatography analysis revealed that D-limonene and cis -cinnamaldehyde were the main components. The antioxidant and antimicrobial activities of the essential oils have been studied by the DPPH radical-scavenging assay and the disc-diffusion method, respectively. All essential oils had antimicrobial activity against saprophytic ( Bacillus subtilis , Penicillium chrysogenum , Fusarium moniliforme , Aspergillus niger , Aspergillus flavus , Saccharomyces cerevisiae ) and pathogenic microorganisms ( Escherichia coli , Salmonella abony , Staphylococcus aureus , Pseudomonas aeruginosa, Candida albicans ), with the highest inhibitory activity being observed in cinnamon oil, followed by grapefruit zest oil, tangerine zest oil and lemon zest oil; the MIC ranging from 6 to 60 ppm. In addition, they exhibited high antioxidant activity with the highest antioxidant activity being determined for the grapefruit zest essential oil, followed by the lemon zest essential oil, the tangerine zest essential oil and the cinnamon essential oil. The demonstrated promising results for the antioxidant and antimicrobial activity of the studied essential oils would give reason for their inclusion in the development of bio-preservation strategies for food emulsion preservation., (© 2020 Walter de Gruyter GmbH, Berlin/Boston.)

This study aims to investigate the chemical composition, antioxidant, and antimicrobial activity of Citrus aurantium L zest essential oil. The identification of the chemical compounds was done using chromatography analysis. The antioxidant activity was studied by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Results showed that the main components of the essential oil were limonene (85.22%), β-myrcene (4.3%), and α-pinene (1.29%). Regarding the DPPH radical scavenging ability, the zest essential oil showed higher activity than limonene. The antimicrobial activity of the essential oil against pathogenic [Staphylococcus aureus NBIMCC 3703, Salmonella sp. (clinical isolate), Pseudomonas aeruginosa NBIMCC 1390, Bacillus subtilis NBIMCC 1208, Escherichia coli NBIMCC 3702] microorganisms by disc-diffusion method was examined. Gram-positive bacteria were more sensitive to the oil (inhibition zones being between 9 and 12.5 mm) and the minimum inhibitory concentration was more than 600 ppm; Gram-negative bacteria were less sensitive. The obtained essential oil displayed promising results for its application as a biopreservative agent.

The growing consumer demand for the development of functional foods with a number of benefits for the consumer has led to a considerable increase in the studies focused on examining different natural agents to be included in the composition of newly developed functional foods. The chemical compositions of the essential oils (EOs) of lavender (Lavandula angustifolia Mill.), peppermint (Mentha piperita L.), raspberry seed (Rubus idaeus L.), and ylang-ylang (Cananga odorata (Lam.)) were determined using gas chromatography with a mass selective detector (GC-MS). The antibacterial and antifungal activities of these EOs were examined using a high-throughput 96-well microplate bioassay procedure and the MICs of each EO against each test microorganism were determined. The results indicated significant antimicrobial activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Salmonella abony NTCC 6017, Pseudomonas aeruginosa NBIMCC 1390, Bacillus subtilis ATCC 19659, Penicillium chrysogenum ATCC 28089, Fusarium moniliforme ATCC 38932, Aspergillus niger ATCC 1015, and Aspergillus flavus ATCC 9643. To explore their potential applications in food preservation, model chocolate mousse food emulsions were prepared that incorporated EOs and/or selected probiotic lactobacilli strains in both free and encapsulated forms. The inclusion of EOs and/or probiotic lactobacilli resulted in enhanced microbial safety and an extended shelf life. Furthermore, the chocolate mousse variants that were biopreserved with the inclusion of probiotic lactobacilli maintained a high viable lactobacillus cell concentration throughout the storage period. As a result, these products would not only be suitable as functional probiotic foods but also as effective delivery vehicles for probiotic lactobacilli. [ABSTRACT FROM AUTHOR]

Introduction. Lactic acid bacteria produce various compounds such as organic acids, diacetyl, hydrogen peroxide and bacteriocin during lactic fermentations. All of these can antagonize the growth of some spoilage and pathogenic bacteria in foods. Materials and methods. To determine the antimicrobial activity of Lactobacillus plantarum D1 and Lactobacillus plantarum D2 against Salmonella sp. and Salmonella abony ATCC 6017, the method of co-culturing was applied. The study was conducted under static conditions at 37±1 ºC for 72 hours, taking samples at 0, 12, 24, 36, 48, 60 and 72 h and monitoring the changes in the titratable acidity and the concentration of viable cells of both the pathogens and the Lactobacillus plantarum strains. Results and discussion. In the single-strain cultivation of each Lactobacillus plantarum strain and each Salmonella strain high concentration of viable cells were achieved by the 24th hour and it was maintained by the end of the culturing. In the co-culturing of each Lactobacillus plantarum strain and each Salmonella strain, the Lactobacillus strain was not significantly influenced by the presence of any of the Salmonella strains. But the number of viable cells of the pathogens was greatly reduced, the reduction being strainspecific. In the co-culturing of each Lactobacillus plantarum strain and Salmonella abony ATCC 6017, the concentration of viable cells of the pathogen strain was reduced by the 60th h. In the co-culturing of each Lactobacillus plantarum strain and Salmonella sp., the concentration of viable cells of the pathogen strain was reduced by the 72th h. The observed antimicrobial activity was due to a great extent to the acidification of the medium because of the production and accumulation of lactic and other oraganic acids. Conclusions. The demonstrated antimicrobial activity is a prerequisite for further research on the probiotic potential of the two Lactobacillus plantarum strains for their inclusion in the composition of probiotic preparations and starters for probiotic functional foods. [ABSTRACT FROM AUTHOR]

Four popular spices black pepper (Piper nigrum L.), cumin (Cuminum cyminum L.), coriander (Coriandrum sativum L.) and cardamom (Elettaria cardamomum) were analyzed for their oil composition by GC-MS. Thirty compounds were identified in the black pepper oil and the main components were β-caryophyllene (20.225 %), sabinene (18.054 %), limonene (16.924 %), a-pinene (9.171 %) and α-phellandrene (5.968 %). Twenty five compounds were identified in the cumin oil - cuminaldehyde (30.834 %), 3-caren-10-al (17.223 %), β-pinene (14.837 %), ϒ-terpinene (11.928 %), 2-caren-10-al (8.228 %) and pcymene (6.429 %). Twenty nine compounds were identified in the coriander oil - ⛚-linalool (58.141 %), β-pinene (8.731 %), ϒ-terpinene (6.347 %) and p-cymene (5.227 %). Twenty nine compounds were identified in the cardamom oil - β-terpinyl acetate (39.032 %), eucalyptol (31.534 %), β-linalool (4.829 %), sabinene (4.308 %) and α-terpineol (4.127 %). The antimicrobial activity of essential oils against pathogenic (Escherichia coli ATCC 25922, Escherichia coli ATCC 8739, Salmonella sp. (clinical isolate), Staphylococcus aureus ATCC 6538P, Proteus vulgaris G) microorganisms by disc-diffusion method was examined. Gram-positive bacteria were more sensitive to the oils (inhibition zones being between 8 and 12.5 mm) and the minimum inhibitory concentration was more than 600 ppm; Gram-negative bacteria were less sensitive. The obtained essential oils are suitable for use as biopreservative agents. [ABSTRACT FROM AUTHOR]