Encapsulation of green tea extract in nanoliposomes and evaluation of its antibacterial, antioxidant and prebiotic properties

Background: The application of natural compounds including green tea extract [GTE] in food and pharmaceutical industries is limited. Encapsulation in nanoliposomes could be used as a delivery system to protect these compounds during processing and storage

Objective: In this study encapsulation of green tea extract in nanoliposomes and evaluation of its antibacterial, antioxidant and prebiotic properties were evaluated

Methods: GTE was encapsulated in liposomes by thin film layer method and reached to nanoscale with sonication. The prebiotic activity of 1% nanoliposomal GTE was evaluated on the growth of lactobacillus casei and bifidobacterium lactis in MRS broth medium. Furthermore, the antioxidant activity of nanoliposomal GTE was estimated by DPPH assay. The antibacterial activity of nanoliposomal GTE against Bacillus cereus [ATCC11778], Salmonella typhimurium 138 phage type 2, E. coli O[157]: H[7] and Listeria monocytogenes [ATCC19118] was determined using well diffusion technique

Results: The mean diameter of nanoliposomes was about 44.7 +/- 1.9 nm and had 0.203 +/- 0.014 polydispersity index. Entrapment efficiency of nanoliposomal GTE under the optimum conditions was 97%. Antibacterial activity of GTE was significantly increased after encapsulation in nanoliposomes. The strongest antibacterial activity of nanoliposomal GTE was seen against listeria monocytogenes with an inhibition zone of 16.2 mm while E. coli was the most resistance strain with an inhibition zone of 14 mm. Furthermore, the antioxidant activity of GTE was significantly increased after nanoliposome encapsulation since the IC[50] value of nanoliposomal GTE was decreased to 1.78 microg ml[-1]. Moreover, addition of 1 % nanoliposomal GTE enhanced the growth rate of Lactobacillus casei and Bifidobacterium lactis to a significant extent

Conclusion: Nanoencapsulation effectively enhanced beneficial properties of GTE

[Effect of Zataria multiflora boiss. essential oil on growth curve and shigatoxin 2 production of enterohemorrhagic Escherichia coli O157:H7]

Zataria multiflora Boiss. is one of the Iranian traditional spices and it has antimicrobial effect on the pathogenic bacteria which are agents for some current foodborne intoxications. The present study was conducted to evaluate the antimicrobial activity of Zataria multiflora Boiss. Essential oil on Escherichia coil 0157:H7. Minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] of Zataria multiflora Boiss. Essential oil [EO] for Escherichia coil 0157:H7 at 35°C, the effect of subinhibitory concentrations of EO on growth curve of bacteria up to 24 hours at 25 and 35°C and also production of shigatoxin 2 [Stx2], at 35°C has been determined. MIC and MBC of EO which have been evaluated were 0.04 and 0.06%, respectively the effect of subinhibitory concentrations of EO on bacterial growth curve during 24 hours has been determined by spectrophotometer device at 25 and 35°C and also production of shigatoxin 2 [Stx2], at 35°C has been determined. Subihibitory concentrations of EO, significantly, decreased the production of Stx2 at 35°C in a dose dependent manner. The results showed that Zataria multiflora Boiss. Essential oil had inhibitory effect on Escherichia coli 0157:H7 and it can be used as a natural preservative in food industry

[Study of chemical composition of essential oil of Afsantine [Artemisia absinthium] and inhibitory effects of the essential oil and its aqueous and alcoholic extracts on some food borne bacterial pathogens]

Increasing human knowledge about adverse effects of chemical preservatives has increased public interest to consume products with natural preservatives such as plant extract and their essential oils. In this study chemical composition of essential oil of Afsantine and antibacterial effect of its essential oil and aqueous, ethanolic and methanolic extracts against the most important food borne pathogens, Salmonella typhimurium, Listeria monocytogenes, E. coli O157:H7, Bacillus cereus and Staphylococcus aureus were evaluated. Gas Chromatography-Mass Spectrometry [GC-MS] method was used for chemical composition analysis of the essential oil. Disk diffusion method was done to screen bacterial sensitivity. The Minimum Inhibitory Concentrations [MIC] of extracts were evaluated by broth micro-dilution method. The essential oil components were identified and the major constituents of the oil were Beta Thujone [29.75%] and Phellandrene [20.20%]. In disk diffusion method the most sensitive strain to the essential oil and the extracts was S. typhimurium and E.coli O157:H7. MICs of Afsantine essential oil against S. aureus and L. monocytogenes were estimated 3000 ppm. The methanolic extract showed antimicrobial activity against L. monocytogenes, E.coli O157:H7, B. cereus and S. aureus were estimated 10, 10, 8 and 4 mg ml-1, respectively. The results of this study revealed that the essential oil and methanlic extract of Afsantine have greater antimicrobial effects on given strains and might be used as a natural preservative in food system.

[Antibacterial effect of aqueous and alcoholic extracts from petal of saffron [Crocus sativus L.] on some foodborne bacterial pathogens]

Health concerns due to adverse effects of chemical preservatives have increased public interest to consuming preservative-free products or product containing natural preservatives such as plant extract and their essential oils. In this study the antibacterial effect of aqueous, ethanolic and methanolic extracts from petal of saffron against the most important foodborne pathogens Salmonella typhimurium, Listeria monocytogenes, E. coli O157: H7, Bacillus cereus and Staphylococcus aureus were evaluated. Disk diffusion method was done to screen bacterial sensitivity. The minimum inhibitory concentration [MIC] of extracts were evaluated by agar dilution and broth microdilution method. The most sensitive strain to extracts was S. typhimurium, and the most resistant strains were S. aureus and E. coli O157:H7. MICs of all extracts were estimated 40 mgml[-1], against all bacteria using agar dilution method. The aqua and methanolic extracts showed antimicrobial activity against all of bacteria by broth microdilution and MIC estimated 40 mgml[-1], however MIC of ethanolic extracts estimated 40 mgml[-1] for L. monocytogenes, S. aureus and B. cereus, while the MICs for S. typhimurium and E. coli O157:H7 were estimated >40 mgml[-1]. The results of this study revealed that the studied extracts might be potential sources of natural antimicrobial agents, and propose their potential application in food system as a natural preservative

[Determination of minimum inhibitory concentration [MIC] of Zataria multiflora boiss. essential oil and Lysozim on E. coli]

In order to reduce or eliminate foodborne pathogens or food spoilage agents many research have been done to find natural preservatives. This study was carried out to determine minimum inhibitory concentration [MIC] of lysozyme and Zataria multiflora boiss. essential oil on E. coli 0157: H7 and their sub inhibitory concentration effect on bacterial growth curve. In this study different concentrations of lysozyme [0. 125, 250, 500 and 1000 micro g/ml] and Zataria multiflora boiss. essential oil [0, 0.005, 0.01, 0.02, 0.04 and 0.08%] were used alone and in combination on BHI broth to determine MIC of Zataria multiflora boiss. essential oil and lysozyme with macro dilution and micro dilution methods and effect of sub inhibitory concentrations of them on bacterial growth curve of E. coli 0157: H7. MIC of essential oil in two methods was achieved 0.04% whereas lysozyme in 100 micro g/ml concentration was not able to reduce bacterial growth. Furthermore combination results revealed that high concentration of lysozyme was not able to reduce calculated amount of MIC of essential oil. Sub inhibitory concentration effect of EO and lysozyme showed that their combination result in the increase of lag phase and reduction of bacterial growth. Utilization of EO and lysozyme together did not decrease MIC but combination of them increase lag phase

[Determination of minimum inhibitory concentration [MIC] of zataria multiflora boiss. essential oil and lysozim on L. monocytogenes]

Application of natural compounds, including essential oils [EOs] and lysozyme is an effective method against growth of bacterial pathogens in foods. Determination of minimum inhibitory concentration [MIC] of lysozyme and Zataria multiflora Boiss. essential oil on L. monocytogenes. In this study different concentrations of lysozyme and Zataria multiflora Boiss. EO were used alone and in combination on BHI broth to determine MIC of Zataria multiflora Boiss. EO and lysozyme with macro dilution and micro dilution methods and effect of sub inhibitory concentrations of them on bacterial growth curve of L. monocytogenes. The minimum inhibitory concentration [MIC] of Z. multiflora Boiss EO was estimated ?0.04 using macro and microdilution. lysozyme at the highest concentration [1000 microg/ ml] was not effective in inhibition of bacterial growth and no MIC value obtained. Combination of EO and Lysozyme decreased the MIC value to%0.02 and 250microg/ mlfor Z. multifloraBoiss. EO and lysozyme, respectively. The results of growth curve analysis showed that combination was effective in increasing the lag phase. Z. multiflora Boiss and lysozyme showed to be effective against bacterial growth and its potential application in food systems may be suggested

[Effect of zataria multiflora boiss. Essential oil on growth and enterotoxin E production of staphylocuccus aureus ATCC 29213]

Z. multiflora Boiss. is one of the Iranian traditional spices and it has antimicrobial effect on the pathogenic bacteria which are agents for some current foodborne intoxications. The present study was conducted to evaluate the antimicrobial activity of Z. multiflora Boiss. Essential oil on Staphylocuccus aureus ATCC 29213. Minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] of Z. multiflora Boiss. essential oil [EO] for Staphylocuccus aureus at 35[degree sign]C, the effect of subihibitory concentrations of EO on growth of bacteria up to 72 hours and also production of entertoxin E [SEE], all at 25 and 35[degree sign]C has been determined. MIC and MBC of EO which have been evaluated in 0.005 - 0.06% [V/V] were 0.03 and 0.04%, respectively. Colony counting during 72h showed that 75%MIC of EO in 72h reduced 3 log [cfu/ml] at 25[degree sign]C and 2, 2 and log [cfu/ml] at 35[degree sign]C in comparison with control culture. Subihibitory concentrations of EO, significantly, decreased the production of SEE at both 25 and 35[degree sign]C in a dose dependent manner. The results showed that Z. multiflora Boiss. essential oil had inhibitory effect on Staphylocuccus aureus and it can be used as a natural preservative in food industry

[Effect of zataria multiflora boiss essential oil and nisin on shelf life in light salted fish fillet of silver carp [hypophthalmichthys molitrix]]

Zataria multiflora is medical plants in Traditional Medicine of Iran. It is necessary to study on antimicrobial effects of essential oil on foodborne pathogens. Nisin is bacteriocin, antimicrobial food preservative. It is regarded as natural because it is a polypeptide produced by certain strains of Lactococcus lactis subsp. lactis [hereafter referred to as L. lactis], during fermentation. This study was performed to evaluate the antimicrobial effects of Zataria multiflora Boiss essential oil and Nisin on the shelflife of light salted fish fillet, silver carp. Effects of different concentrations, Zataria multiflora Boiss essential oil [0, 0.045, 0.135, 0.405 and 0.810%] and Nisin [0, 0.25 microg/ml] were studied on shelf life in light salted fish fillets of silver carp at unfavourable refrigeration storage temperature [10 C] by measuring of microbial flora and chemical values such as pH, thiobarbituric acid [TBA] and total volatile basic nitrogen [TVB-N] and perioxide compared with control group. The results showed that higher used concentrations of Zataria multiflora essential oil [0.135, 0.405 and 0.810%] and Nisin [0.25%] had a significant effect on the shelf life of fish fillets [p> 0.05]. The results showed that Z. multiflora essential oil and nisin have antimicrobial effects and are as a food natural preservative in fish fillet. Also, Total volatile basic nitrogen [TVB-N] increased with growth of microbial flora and TVN in the study was best factor for shelf life changes

[Growth inhibition and morphological alterations to Penicellium citrinium in response to Zataria multiflora Boiss. essential oil]

The growing interest in substitution of chemical food preservative with natural ones has fostered researches on plant essential oils and extracts. The purpose of the current study was to evaluate the effect of Zataria multiflora Boiss. essential oil on growth respose, the percent of growth inhibitory and morphology of Penicellium citrinum. Different concentrations of the essential oil [0, 50, 100, 200, 400, 600 ad 1000 ppm] were used in agar dilution method to evaluate growth and spore production parameters. The cultured mold were studied by scanning electron microscope. Values among groups were compared using 1-way ANOVA. It was found that the effect of different concentrations of essential oil on radial growth and sporulation was statistically significant [p<0.05]. The minimum inhibitory concentration [MIC] and minimum fungicidal concentration [MFC] both were 400ppm. According to scaning electron microscopy the treatment with the oil led to alterations in hyphal morphology. Our results suggest that Zataria multiflora Boiss. essential oil can be used as a natural preservative against Pencillium citrinum in foods

[Effect of zataria multiflora boiss. essential oil on enterotoxin production by staphylococcus aureus ATCC 6538]

Staphylococcal food poisoning does not result from the ingestion of S. aureus per se, but rather from enterotoxins which are pre-formed within the food. There is no report on effect of Zataria multiflora Boiss. essential oil on enterotoxin production by this microorganism. The aim of this study was to evaluate the effect of different concentrations of Zataria multiflora Boiss. essential oil on enterotoxin production by S. aureus. This study was done as a factorial model using different concentrations of EO [0, 0.005, 0.015 and 0.03%].The bacterial growth was evaluated during 43 days of incubation and enterotoxin production was analyzed using a enterotoxin assay kit. The growth of the organism was completely inhibited by the EO=0.03%. Enterotoxin production was not affected by sub-inhibitory concentration of EO at level of 0.005%, while it was significantly [p < 0.05] inhibited by increasing subinhibitory concentration of EO to 0.015%. The adverse effect of sub-inhibitory concentration of Zataria multiflora Boiss. EO on enterotoxin production by S. aureus, demonstrated in this study, suggests the potential application of this EO as a natural antimicrobial in foods

[Effect of Zataria multiflora Boiss. essential oil on the behavior of Vibrio parahaemolyticus in salted fish]

Thyme [Zataria multiflora Boiss.] is one of the Iranian traditional spices and it has antimicrobial effect on the pathogenic bacteria which are agents for some current food borne intoxications. The aim of this study was to evaluate the antimicrobial activity of Zataria multiflora Boiss. essential oil on V. parahaemolyticus in salted [8% Nacl in tissue] silver carp. Effect of different concentrations of this Essential oil [0.0%, 0.045%, 0.135%, 0.405%, 0.810%] on behavior of V. parahaemolyticus in two temperatures [15, 25 C] was determined by evaluation of the bacterial growth in salted fish fillets. The essential oil in used concentrations had significant inhibitory effect on the growth of V. parahaemolyticus in salted fish compare with control treatment during the storage time [p<0.05]. There was no significant difference between all treatments. The results showed that Zataria multiflora Boiss. Essential oil had inhibitory effect on V. parahaemolyticus, therefore it can be considered as a natural preservative in salted fish

Fate of Listeria monocytogenes during the manufacturing process of Iranian white brined cheese as affected by Zataria Multiflora Boiss. Essential oil

There are many reports about the isolation of Listeria monocytogenes from different kinds of cheese. Natural preservatives such as Zataria multiflora Boiss. Essential oil can inhibit the growth of foodborne pathogens. Evaluation of antibacterial effect of Zataria multiflora Boiss. Essential oil on Listeria monocytogenes in Iranian white brined cheese. The essential oil of this plant were obtained by hydrodistilation and analysed by GC/MS. Effect of different concentrations of this essential oil [0,50, 150 and 300 ppm] on Listeria monocytogenes were evaluated in Iranian white brined cheese. Results showed the significant [p < 0.05] effect of the essential oil at concentrations of 150 and 300 ppmThe results showed, the potential inhibitory effects of the Zataria multiflora Boiss. Essential oil on Listeria monocytogenes in Iranian white brined cheese

[Effects of zataria multiflora boiss. essential oil on aspergillus flavus]

Molds are important spoiler of food material and have potential of mycotoxin production. The adverse side effects of chemical preservatives have caused that research focused on use of naturally occurring compound, especially essential oils [EOs], for inhibition of mold growth. Essential oils are natural compounds containing terpenic mixtures that have antimicrobial and antioxidant properties. Zataria multifloro Boiss., a domestic aromatic plant of Iran, has different effect such as antispasmodic and antibacterial. In this study effect of Z. multiflora Boiss. Essential oil on growth and spore production by Aspergillus flavus and its morphological alteration action were investigated. After extraction of essential oil with steam distillation method, it was analyzed by GC-MS. Evaluation of essential oil effect on growth and spore production carried out by agar dilution method. For SEM evaluation, mold cultured on PDA was fixed with osmium tetroxide and blocks of agar were coated with gold and observed by scanning electron microscope. Effect of EO on growth and spore production by A. flavus was significant in all concentrations studied. MIC and MFC values were 400 and 1000 ppm, respectively. SEM analysis showed excessive sporulation of mold culture in absence of EO while sporulation of culture containing EO was very sparse. Morphological changes such as irregular surface with many folds and distortion of hyphae were seen in cultures treated with EO. Inhibitory effect of Z. multiflora Boiss. Essential oil demonstrated in this study candidate this EO as a substitution of chemical preservatives

Evaluation of Zataria mutiflora boiss. Effect on staphylococcus aureus in Feta Cheese

Thyme [Zataria multiflora Boiss] is one of the Iranian traditional spice and it has antimicrobial effect on the pathogenic bacteria which are agents for some current food borne intoxications. Evaluation of antimicrobial effect of mentioned plant essential oil on Staphylococcus aureus in Feta cheese. The essential oil of this plant was obtained by hydrodistillation and analyzed by GC/MS. Effects of different concentrations of this essential oil on Staphylococcus aureus were determined by evaluation of the microorganism growth on the selective media in laboratory, and these effect on the growth of Staphylococcus aureus and when the mentioned concentrations of the essential oil were used in combination with cheese starter culture, the counts of the pathogen were decreased significantly below its toxic dose in this kind of food product. The antimicrobial effect of Zataria multiflora Boiss. in 300 ppm was higher than its lesser concentrations and with concern to the control groups, the synergistic effect between the starter and the essential oil is necessary to achieve this inhibitory effect