جستجوی مقالات مرتبط با کلیدواژه « natural preservative » در نشریات گروه « صنایع غذایی »

Adding chemical preservatives increases the shelf life of food products, but long-term and indiscriminate use of chemical preservatives increases the resistance of microorganisms and health risks associated with their absorption. Medicinal plants have a great diversity both in the world and in Iran and have the potential to be used as alternatives to chemical compounds. In this study, the antimicrobial effect of Pterocarya fraxinifolia essential oil against Bacillus subtilis, Streptococcus pyogenes, Staphylococcus aureus, Shigella dysenteriae, Enterobacter aerogenes, and Salmonella typhi was investigated by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration. The total phenol and flavonoid content of the essential oil was determined using Folin Ciocalteu and aluminium chloride methods, respectively. The antioxidant activity of the essential oil was evaluated using two methods of inhibiting free radicals DPPH and ABTS. The total phenol and flavonoid content of the essential oil was 38.63 mg of gallic acid/g and the flavonoid content was 19.20 mg of quercetin/g. The essential oil of P. fraxinifolia was able to inhibit free radicals DPPH (58.60%) and ABTS (59.80%). The results of the antimicrobial activity of the essential oil by the disk diffusion agar and well diffusion agar methods showed that B. subtilis and E. aerogenes are the most sensitive and resistant microbial strains to the essential oil, respectively. The minimum inhibitory concentration for these bacteria was 2 and 64 mg/mL, respectively, and the minimum bactericidal concentration was 32 and > 512 mg/mL, respectively.

The aim of this study was to determine the total phenol and flavonoid content and investigate the antioxidant and antimicrobial activity of Perovskia abrotanoides essential oil. The total phenol content was determined using the Folin Ciocalteu method, the total flavonoid content using the colorimetric aluminum chloride method, the antioxidant potential using the DPPH and ABTS free radical inhibition methods, and the antimicrobial activity using the disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. The total phenol, total flavonoid, DPPH free radical inhibition, and ABTS free radical inhibition of the essential oil were found to be 24.26 mg of gallic acid per gram, 13.15 mg of quercetin per gram, 52.49%, and 56.79%, respectively. The antimicrobial results showed that the antimicrobial effect of the essential oil was higher against Gram-positive bacteria than Gram-negative types, and Staphylococcus aureus and Salmonella typhi were the most sensitive and resistant microbial strains against P. abrotanoides essential oil, respectively. The diameter of the growth inhibition zone in the disc diffusion agar and well diffusion agar tests, as well as the minimum inhibitory and bactericidal concentrations for S. aureus, were 16.50 mm, 17.30 mm, 2 mg/mL, and 128 mg/mL, respectively, and these values for S. typhi were 7.60 mm, 9.20 mm, 16 mg/mL, and 512 mg/mL, respectively. In general, P. abrotanoides essential oil can be used as a natural antioxidant and antimicrobial compound.

Datura stramonium is well known as a valuable drug in many diseases including inflammation, wounds, fever and toothache, and its extract has significant antimicrobial activity. Therefore, this study was performed to isolate the ethanolic extract of D. stramonium leaves and to investigate its antimicrobial activity. In this study, D. stramonium extract was obtained using the maceration method. Antimicrobial methods of disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration were used to determine the antibacterial activity of ethanolic extract of D. stramonium leaves against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Bacillus cereus. The antimicrobial activity of the extract was concentration dependent and the highest diameter of growth inhibition zone was observed at a concentration of 60 mg/ml of the extract. According to disk diffusion agar and well diffusion agar tests, S. aureus and S. typhimurium had the highest and lowest diameter of growth inhibition zones, respectively. The minimum inhibitory concentrations for E. coli, S. typhimurium, S. aureus and B. cereus were 16, 16, 8 and 8 mg/ml, respectively, and the minimum bactericidal concentrations for these bacteria were 256, 256, 64, and 128 mg/ml, respectively. In general, Gram-positive bacteria were more sensitive to the extract than Gram-negative types. Ethanolic extract of D. stramonium leaves can be used as a natural antimicrobial agent to prevent the growth of pathogenic bacteria and treat related diseases.

This study aimed to produce tomato paste using natural preservatives as an alternative to chemical preservatives. Fennel seed extract (Foeniculum vulgare Mill) and Ziziphora clinopodioides Lam. were used as natural preservatives.Physicochemical properties of tomato paste such as pH, acidity and total soluble solids (Brix) were measured during 5 weeks of storage at 4°C. Sensory properties of tomato paste were assessed using trained and untrained sensory evaluators using a 5-point hedonic scale.To predict the data from an artificial neural network of topology 2-37-1, storage period and different concentrations of fennel seed extract and Ziziphora clinopodioides Lam. were considered as inputs and acidity as the target parameter.The results showed that using different concentrations of fennel seed extract and Ziziphora clinopodioides Lam. significantly reduced (p <0.05) the pH and increased the acidity of tomato paste.Increasing the level of extracts in tomato paste samples significantly (p <0.05) increased Brix during storage period.Sensory evaluation showed that in terms of color, appearance and consistency treatments containing low concentrations of the extracts (0.5 and 1% of both extracts) scored higher.In terms of taste and smell, treatments 3 and 4 (containing 2 and 3% of fennel seed extract, respectively) had the highest score.In general, it can be concluded that using 2 or 3% fennel seed extract as a natural preservative in tomato paste leads to desirable physicochemical and sensory properties.The results of acidity prediction showed that the correlation coefficient and the mean squared error for the total data were 0.99232 and 0.00002, indicating a successful prediction.

Strawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste is a costly process and the hazardous waste causes serious environmental problems. In addition, fungal pathogens have shown a worrying trend of resistance to these fungicides, thus shortening the shelf life of products. Compounds that can be equally effective in controlling pathogens, but preventing or minimizing the waste problems will be inevitable. The large volume of internationally processed agricultural products, as well as the increasing demand for organically produced fruits, emphasizes the need to replace synthetic fungicides with safer and biodegradable alternatives. Natural plant-derived products effectively meet this criterion and have great potential to influence modern agricultural research. Catechins and other polyphenols in green tea show strong antioxidant activity. Also, the antimicrobial activity of green tea extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans has been reported. Therefore, the present study was performed to prepare the ethanolic extract of green tea and to determine the content of total phenol, total flavonoids, antioxidant activity, and its antifungal effect against Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer (causing rot in strawberry and grapes).

Fresh green tea leaves were dried at room temperature and then powdered. Then, ethanol (70%) was added to the powdered leaves (solvent to powder ratio of 10:1 v/w) and the mixture was refluxed for 120 min. The resulting mixture was filtered through a filter paper and then concentrated under vacuum and finally dried in an oven.Total phenol content (by Folin-Ciocalteu reagent at 756 nm), total flavonoid content (spectrophotometrically at 510 nm), antioxidant activity (by DPPH and ABTS radical scavenging methods), and antifungal effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated.

The extract contained 175.60 mg GAE /g total phenol and 47.53 mg QE/g total flavonoids and its antioxidant activity using DPPH and ABTS free radical assays was 78.89% and 86.57%, respectively. The results of antifungal activity showed that the diameter of the growth inhibition zone increased significantly with increasing the concentration of the extract, and Botrytis cinerea and Rhizopus stolonifer were the most sensitive and resistant fungal strains to the extract, respectively. The minimum fungicidal concentrations for the strains of Botrytis cinerea and Rhizopus stolonifer were 64 and 512 mg/ml, respectively.

The results of the present study showed that the ethanolic extract of green tea could be considered as potential source of natural antioxidant and antifungal agents. The presence of phenolic and flavonoid compounds may be responsible for the antifungal and antioxidant effects of the extract. However, due to the fact that this study was performed with the crude extract of green tea, it is difficult to identify compounds responsible for antifungal and antioxidant activity. On this point, only the separation of the components of the extract allows the detection of antifungal and antioxidant compounds. This study provides a basis for further researches, in particular the use of these antioxidants and antifungal compounds. Green tea extract is especially suitable for products with high sensitivity to lipid oxidation and infection with molds.

Satureja and Tarragon Extracts as natural preservative for mayonnaise sauce: physicochemical, microbial and sensory analysisAbstract mayonnaise sauce is oil in water emulsion that has numerous consumption. As there is no heating process during production of mayonnaise sauce, using preservatives is necessary. On the side of this, concern about chemical preservatives caused a development in formulation with natural preservatives. Traditional plants are one of the antimicrobial component sources that extraction and use of them in foods could be step for achieving above goal. The objective of this study was using natural preserving properties of Satureja and Tarragon extracts as substitute of chemical preservatives in mayonnaise sauce and investigating its changes. In this study, alcoholic method was used for extracting. After investigating antimicrobial effect of extracts in culture, selected extracts according with experimental design were added to mayonnaise. In order to determination of experimental treats, mixture design with 3 variables (chemical preservative, Satureja and Tarragon extract) was used. Combination of these variables led to an experimental design with 16 runs. Intended extracts were added to mayonnaise sauce formulation and physicochemical experiments such as pH, acidity, colorimetery and sensory evaluation were done. Also antimicrobial effect of extracts against important microorganisms in mayonnaise sauce (Lactobacillus, Salmonella and yeast and molds) was evaluated. Relation of each dependent variable with independent variables was showed via proper equation and their contour graph was drawn by design expert software. Results of antimicrobial test showed that using Satureja and Tarragon extracts decreased the population of yeast, Lactobacillus and Salmonella during 3 month of storage. In all samples, pH and acidity range was according to ISIRI standard of mayonnaise sauce. Colorimetric assay showed using Satureja and Tarragon increased a* and decreased L*. In terms of sensory evaluation, it was shown that samples containing Satureja and Tarragon extracts had lower score than sample containing chemical preservative. to determination of optimum formulation of mayonnaise sauce, range or goal of intended properties was specified and considering them, optimum formulation was presented by software. In this formulation, 18.88% chemical preservative (136.41ppm), 34.49 % Satureja extract (27595 ppm) and 47.31% Tarragon extract (37855 ppm) led to mayonnaise sauce formula with capability of using natural preservative and acceptable physicochemical and sensory characteristics.18.88% chemical preservative (136.41ppm), 34.49 % Satureja extract (27595 ppm) and 47.31% Tarragon extract (37855 ppm) led to mayonnaise sauce formula with capability of using natural preservative and acceptable physicochemical and sensory characteristics.Keywords:Satureja , Tarragon, mayonnaise sauce, antimicrobial, sensory evaluation

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.

Oxidation and food pathogens are considered two important and influential factors affecting food quality and health. Recently, due to the increasing demand for natural products, the application of synthetic preservatives to control microbial growth and lipid oxidation have been decreased significantly. Therefore, natural antioxidant and antimicrobial compounds are receiving more attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased. Furthermore, secondary metabolites in plant extracts and essential oils are able to control and inhibit free radical-mediated reactions. The olive tree (Olea europaea) is an evergreen plant that grows in tropical and subtropical regions. Iran is one of the most important olive growers in the world due to its suitable conditions for olive cultivation. The leaves of the olive plant have a high potential for the production of various products such as tea and extracts. Olive leaf extract can be used as a raw material in the production of various products, due to exhibiting various biological activities such as antimicrobial and antiviral activity, lipid stabilizer, blood pressure regulator, antioxidant activity, and free radical scavenger. The leaves of the olive tree also contain various phenolic compounds, mainly Oleuropein and hydroxytyrosol, with antioxidant and antimicrobial activities. Therefore, in this study, the amount of phenolic and flavonoid compounds of olive leaf ethanolic extract and its antioxidant effect and antimicrobial properties on Escherichia coli, Enterobacter aerogenesis, Bacillus cereus and Listeria innocua were investigated. 

The olive leaf ethanolic extract was prepared through maceration method and its total phenolic content (Folin-Ciocalteu method), total flavonoids content (aluminum chloride colorimetric assay), antioxidant activity (ABTS and DPPH free radical scavenging methods), and antimicrobial effect on E. coli, E. aerogenesis, B. cereus and L. innocua (based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) were determined according to standard methods. Data were analyzed by SPSS software through one-way ANOVA and Duncan test at p<0.05.  

The ethanolic extract of olive leaves contained 176.58 ± 0.72 mg GAE/g total phenol and 69.85 ± 0.26 mg QE/g total flavonoids. In addition, ethanolic extract of olive leaf was able to inhibit free radicals DPPH (70.62 ± 0.59%) and ABTS (76.15 ± 0.43%). The antimicrobial results showed that the antimicrobial effect of the extract depended on its concentration and type of bacteria. Antimicrobial effect was increased as a function of ethanolic extract, and Gram-positive bacteria (B. cereus and L. innocua) were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria (E. aerogenesis and E. coli). Generally, B. cereus and E. aerogenesis were the most sensitive and resistant microbial strains to ethanolic extract of olive leaf, respectively.The results of this study showed that the high antioxidant and antimicrobial activity of olive leaf ethanolic extract is mainly due to its phenolic and flavonoid compounds. Olive leaf ethanolic extract was able to neutralize DPPH and ABTS free radicals. Also, Gram-positive bacteria were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria. In general, the ethanolic extract of olive leaf can be used as a nutraceutical to control or prevent the growth of spoilage/infection-causing microorganisms and free radical reactions in food and the human body. However, more in-depth studies are needed to determine the mechanism of antimicrobial and antioxidant effects of olive ethanolic extract in vitro and in vivo.

In this study, the ethanolic extract of Humulus lupulus was prepared by the maceration method. Its antimicrobial effect was evaluated against pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Enterobacter aerogenes) through disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration. Total phenol and flavonoid contents of the extract were measured by Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activity of the ethanolic extract was also measured by DPPH and ABTS free radical scavenging methods. The highest and lowest inhibition zones in disk diffusion agar (16.9 mm vs. 12.5 mm) and well diffusion agar (17.6 mm vs. 13.9 mm) methods were accounted for S. aureus and E. aerogenes, respectively. Gram-positive bacterial species were more sensitive to H. lupulus ethanolic extract compared to Gram-negative ones. Total phenol and flavonoid contents of the extract were found to be 96.47 mg GAE/g and 28.5 mg QE/g, respectively. The antioxidant effects of the H. lupulus ethanolic extract, based on DPPH and ABTS radical scavenging activities, were 58.63% and 66.5%, respectively. Based on the results, the ethanolic extract of H. lupulus could be used as a natural antimicrobial and antioxidant agent to inhibit the growth of pathogenic bacteria and lipid oxidation progression in various food products.

Due to the high amount of pH, moisture and protein content, chicken meat is a sensitive product which could be a good host for pathogen and spoilage microorganisms. In the recent years there has been a remarkable attention to use natural preservative instead of chemical preservative among producers of food products. Different studies has shown rosemary essential oil contain antioxidant and antimicrobial properties. The present study was conducted to evaluate effect of rosemary essential oil (free and nanoemulsion) on chemical, microbial and sensorial quality of chicken fillet during refrigerated storage. Samples were examined in days of 0, 3, 6, 9 and 12. The results showed noticeable effects of both forms of rosemary essential oils in microbial, chemical and sensorial quality improvement. Moreover the results indicated that nanoemultion form of rosemary had significant effects on delaying the increase trend of psychrophilic, ,enterobacteriacea and mesophilic bacterial counts as compared to free form of rosemary (P<0.05). Furthermore The results of TVN, TBA and pH measurements indicated that nanoemulsion form of rosemary improved chemical quality of the samples in comparison with free form of rosemary during storage time (P<0.001).  Also in terms of sensorial characteristics, application of nanoemulsion essential oil lead to improvement of odor and overall acceptance factors compared to control group after twelve days of storage.

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.

Encapsulation is one of the most important methods to protect essential oils from evaporation, degradation, and preservation of antimicrobial properties for reducing the number of microorganisms in food. Based on GC/MS analysis, Pulegone (33.10 %), Carvacrol (10.60 %), Piperitenone (9.33 %), Eucalyptol (8.01 %), γ-Terpineol (5.46 %), L- Menthone (4.79 %) were as the major components of phytochemicals of Ziziphoria clinopodioides essential oil (ZEO). Encapsulation of ZEO using maltodextrin and gum arabic in a ratio of 1:1 with different concentrations of 10 %, 20 % and 30 %  (w/w) wall, and concentration of 2.5 % (w/w) ZEO by spray drying method was done. Emulsion characteristics were pH = 3.8, particle size = 429 nm, polydispersity index PDI=0.681 and zeta potential = -25.8 mV. The results showed that the best operating conditions for encapsulation of ZEO using maltodextrin and gum arabic by spray drying method, is selection of concentration of 30 % (w/w) wall with ratio of 1:1 and concentration of 2.5 % (w/w) ZEO. The final microcapsul with pH = 4.7, moisture of = 0.9 %, particle size <20 µm, total oil content 4.655 %, surface oil 0.018 %, oil retention 60 %, encapsulation efficiency  96.65 %, zeta potential = -22.7 mV, polydispersity index (PDI) = 0.375 and water-soluble property with light yellow color and without sediment was produced. Spray drying method is a suitable method for encapsulation of ZEO. ZEO is insoluble in water, but a water-soluble microcapsule can be produced with using this method. Due to the antioxidant and antimicrobial properties of zeo, it can be used as a natural and effective preservative in reducing pathogenic bacteria and increasing the shelf life of food.

Synthetic preservatives, especially nitrite in food, are considered to cause chronic diseases to the human body because of their toxic effects. The per capita consumption of meat products in Iran is 2.5 to 5.5 kg per year, and due to the lifestyle changes of the Iranian families, this consumption is ascending. Therefore, cumulative intake of this preservative could be a warning. By replacing all or a part of nitrite with natural preservative its usage could be eliminated. The aim of this study was to prepare a mixture of natural preservatives from three plant extracts, i.e. clove, eucalyptus and rosemary. To this end, the hydroalcoholic extracts of the plants were obtained and then mixed in a ratio of 3:1:1 of Cloves, Eucalyptus and Rosemary, respectively. Later, Then the mixture was dried on a magnetic stirrer at 50 °C and finally turned into powder by a laboratory mill. Antimicrobial, antifungal, antioxidant properties as well as cytotoxicity effects of the mixed extract were evaluated. Six samples of the chicken sausages were produced with different ratios of the natural preservative to nitrite including 5:0, 4:1, 3:2, 2:3, 1:4 and 0:5. All the samples were evaluated in the terms of color, sensory properties and microbial indices at the periods of 15 and 30 days at 4°C. The results showed that the natural preservative had antimicrobial, antifungal and antioxidant properties and the sausage sample contains 100% natural preservative in terms of sensory properties, microbial indices and color evaluation was the most desirable one. The findings of the present study suggest the application of the clove, eucalyptus and rosemary mixed extract suggested as a safe alternative in chicken sausages and other meat products in food industry.

Today, increasing attention is paid to natural antioxidants and preservatives, including plant extracts. The aim of this study was to identify the functional groups of bioactive compounds, antioxidant activity, total phenol and total flavonoids of ethanolic, aqueous and hydroalcoholic extracts of red bell pepper. Red bell pepper extracts were extracted using ethanol, water and a mixture of water and ethanol (50-50%), respectively. Factor groups were qualitatively identified and investigated by Fourier transform infrared spectroscopy (FTIR). Total phenol was calculated using Folin-Ciocalteu reagent and the number of total flavonoids was calculated by aluminum chloride colorimetry. The antioxidant activity of red bell pepper extracts was evaluated by DPPH and ABTS free radical scavenging tests and the decay of color of beta-carotene/linoleic acid. The presence of C-C and OH groups of polyphenolic compounds of red bell pepper extract was confirmed by FTIR. The phenols of ethanolic, aqueous and hydro-alcoholic extracts of red bell pepper were equal to 22.68, 19.50 and 20.80 mg GAE / g, respectively. The flavonoid content of ethanolic, aqueous and hydro-alcoholic extracts were calculated to be 39.30, 29.28 and 33.70 mg QE / g, respectively. Antioxidant capacity of red bell pepper extracts based on radical scavenging activity of DPPH, ABTS and decay of color of beta-carotene/linoleic acid, 53.39, 59.38 and 56.88 percent for ethanolic extract, 46.37, 51/28 and 48/20 percent for aqueous extract and hydro-alcoholic extract were 51, 57.66 and 49.60 percent. According to the results, it seems that ethanolic, aqueous and hydroalcoholic extracts of red bell pepper can be used as antioxidants and natural preservatives in the food industry to prevent oxidation of food products.

Given the rise in the infectious diseases caused by pathogens, identification of medicinal plants and purification of their nutraceuticals can be useful in treating such diseases. In this experimental study, the antimicrobial activity of Dezfuli orange peel essential oil was examined on 3 Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi) and 5 Gram-positive strains (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Staphylococcus epidermidis and Listeria innocua) through agar disc diffusion, agar well diffusion, minimum inhibitory concentration (microdilution broth) and minimum bactericidal concentration. Furthermore, the interactions between the essential oil and chloramphenicol, gentamycin and tetracycline were investigated. The results of disc diffusion showed that the longest and shortest diameters of the growth inhibition zone belonged to B. cereus (21.20 mm) and L. innocua (13.20 mm) respectively. In the agar diffusion test, S. aureus and E. coli respectively had the longest (17.30 mm) and shortest (11.10 mm) diameters of the inhibition zone. The minimum inhibitory concentration was equal to 25, 400, 50, 12.5, 25, 25, 400 and 12.5 mg/ml for E. coli, P. aeruginosa, S. typhi, S. aureus, B. cereus, B. subtilis, S. epidermidis and L. innocua respectively. The minimum bactericidal concentration of the essential oil was greater than 400 mg/ ml for all the strains.

Clove and Fennel have been widely used in traditional medicine for treatment of diseases. Regarding the existence of the active biological compounds in these plants, it seems that these plants have considerable antibacterial effects.In this experimental study, the Kirby–Bauer, the dilution method in the liquid medium and minimum bactericidal concentration (MBC) were used to evaluate and compare the antibacterial effects of the Clove and Fennel essential oils. The interactions were determined by calculating fractional inhibitory concentration (FIC), according to the European Committee for antimicrobial susceptibility testing protocol. The checkerboard method was performed using 96-well microtiter plates. The results showed that Staphylococcus epidermidis was the most sensitive strain to Clove and Fennel essential oils. The effects of interaction of Clove and Fennel essential oils with chloramphenicol antibiotic on all bacteria showed synergistic status (except for the fennel essential oil on Bacillus cereus). Calculation of fractional inhibitory concentration indicated that there was no interaction between the Clove and Fennel essential oils on Salmonella typhi, Enterobacter aerogenes and Staphylococcus epidermidis. Regarding the checkerboard data, one FICIs (>0.5 to 1) indicated the additive effect (Bacillus cereus). Bacillus cereus is one of the most important bacteria that causing food poisoning, it is possible to use a combination of Fennel and Clove essential oils as a natural preservative in the food industry.

The plant Stachys schtschegleevii is used in the Iranian traditional medicine for the treatment of bacterial infections, rheumatism fever, and inflammatory diseases. In this study, the maceration extraction method with ethanol and water was used to obtain S. schtschegleevii extract, and extraction yield, total phenol content, and antioxidant and antimicrobial activity of the obtained extracts were evaluated. The extraction yield of S. schtschegleevii ethanolic extract was higher than that of aqueous extract (8.8±0.27 vs. 6.9±0.33%), and its total phenol content was also higher compared to the aqueous one (55.35±0.28 vs. 49.4±0.62 mg gallic acid/g dried extract). Antioxidant activity based on IC50 showed that the ethanolic extract, due to its higher total phenol content, has the ability to deactive and neutralize free radicals more efficiently in comparison to the aqueous extract. Antimicrobial results (disk diffusion agar, minimum inhibitory concentration and minimum bactericidal concentration) indicated that bacteria Staphylococcus aureus, Listeria innocua, Escherichia coli and Pseudomonas aeruginosa were more sensitive to the ethanolic extract, and at the same concentration of ethanolic and aqueous extracts, gram-positive bacteria (Staphylococcus aureus and Listeria innocua) had higher sensitivity than the gram-negative ones (Escherichia coli and Pseudomonas aeruginosa). Thus, S. schtschegleevii extract rich in phenolic compounds with appreciable antimicrobial and antioxidant activity could be used as an ingredient to increase nutritional value and shelf-life of food products.

The tendency to use natural preservatives for food security has spread. The objective of this study was to compare the antimicrobial properties of orange peel essential oils with potassium sorbate as a chemical preservative in cup cakes. In order to extract the essential oils from orange peel ultrasound was used at 70% and 90% at 3 and 5 minutes. The results showed that by increasing the time and intensity of sound for extraction of essential oils, efficiency of extraction was increased and extraction time decreased, and also by using essential oils significant changes on dough pH reduction, increasing specific volume and firmness of the final product were observed. However, the reduction of L* and b* values and increasing a* value were observed in this condition. It should be noted that the negative effect of potassium sorbate on the technological properties of cakes and reducing its quality was more than orange peel extract. Samples containing extracted orange oil by 70% ultrasound over 3 minutes, had significant results on technological characteristics and sensory properties especially texture and flavor. The results showed that microbial inhibitory of orange peel essential oils on the growth of mold and yeast was comparable with potassium sorbate. By increasing the time and intensity of sound antimicrobial effect of essential oils was increased.

This study was carried out to evaluate antioxidant and antimicrobial activity of followers of four Iranian varieties of safflower including Arak2811 Zarghan279، Isfahan14 and Varamin295. The flower were dried and extracted with methanol and water mixture. Ferric reducing antioxidant power and β-carotene bleaching assay were used to determine antioxidant activity. Antibacterial potential of extracts was determined with Broth Dilution method. Result showed Arak2811 had highest antioxidant activity in both experiment as Its FRAP value and EC50 in β-carotene bleaching were 0. 32±0. 02 Fe2+/mg dry weight and 2068. 44±15. 64 ppm respectively. Isfahan14 variety was more efficient in evaluation of antimicrobial activity. MIC against Staphylococcus aureus and Salmonella typhi were 30 and 60 mg/ml respectively.

In this research, antimicrobial activity of extract of Salvia leriifolia were investigated with different concentrations of the extract (5000, 10000, 15000 and 20000 mg/kg) on Staphylococcus aureus count and Total viable count in hamburger at different time intervals: after treatment (day 0) and after storage for 15, 30 and 45 day at -12˚C, all microbiological analyses performed at 3 replication. The results showed that both of microbial total count and the number of Staphylococcus aureus in all samples with different concentrations of extract, decreased during storage. This decreasing effect was significant on day 15 and 30 for Staphylococcus aureus and total count, respectively. Our data also showed that the extract of Salvia leriifolia at highest concentration (20000 mg/kg) caused maximum reduction compared to other concentrations and extract at lowest concentration (5000 mg/kg) was less effective in initial Staphylococcus aureus population and microbial total count. These data indicate that Salvia leriifolia extract can exhibit antimicrobial activity against Staphylococcus aureus; so it can be considered as an alternative natural preservative in food products.