IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2020 | Volume:17 | Issue:104|Papers Count:14

Shirazi thyme with the scientific name of Zataria multiflora Boiss is an aromatic seasoning shrub related to Lamiaceae family. In traditional medicine, this herbal plant has been used as a flavoring agent, food and beverages preservative, respiratory tract infection treatment, preventing fluctuation and as antispasmodic, disinfectant and anaesthetic drug. The aim of this investigation was to assess the antibacterial activity of Zataria multiflora essential oil (ZMEO) as alone and in combination with gentamicin and chloramphenicol antibiotics against some foodborne pathogenic bacteria. To determine the mutual pharmaceuticaleffect of ZMEO with the gentamicin and chloramphenicol antibiotics, the subminimum inhibitory concentration (sub-MIC) method was used. Disk diffusion agar and well diffusion agar were also used to determine the inhibition zone diameter of ZMEO. Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed using with microdilution broth and pour plate techniques, respectively. Results showed that Gram-negative bacteria had higher inhibition zone diameter as compare with Gram-positive ones. In case of simultaneous application of ZMEO with gentamicin and chloramphenicol antibiotics, the inhibition zone diameter for Listeria innocua was significantly increased. The MIC of ZMEO for Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli, Staphylococcus aureus and Listeria innocua were determined as 0. 50, 0. 25, 0. 50, 0. 25 and 0. 25 mg/mm, respectively. The MBC of ZMEO for all the pathogenic strains was 2 mg/mm. According to the result of this study, Shirazi thyme has a great potential as a preservative in food industry in addition to its application as seasoning agent and herbal-tea production.

The use of coconut powder in the formulation of flavored milk with regard to its tocopherol and phytosterolcompounds can increase the nutritional value of milk and its organoleptic acceptability among consumers. However, one of the major challenges in the flavored milk industry is their physical instability, which can be effective in using hydrocolloids at the appropriate concentration. Therefore, the aim of this study was to determine the optimal formulation of coconutmilk containing tragacanthin gum (solution of tragacanth) to achieve a product with Desirable quality characteristics. For this purpose, the response surface method with the central composite investigated the effect of tragacanthin gum on 5 levels (0, 0. 075, 0. 15, 0. 225 and 0. 3%) and coconut powder on 5 levels (2, 3. 5, 5, 6/5 and 8%) on the physical, chemical and sensory properties of coconut milk was used. Statistical results showed that increasing coconut powder and tragacanthin gum in coconut milk formulation significantly decreased pH and increased acidity (p<0. 05). According to the results of the viscosity test, the viscosity increased as the formulation of tragacanthin and coconut powder increased (p<0. 05). results show an increase of sedimentation amount once the coconut powder increased. While by increasing the gum tragacanthin concentration, there was a twofold effect in sedimentation amount and in average level of gum, the minimum amount of sediment was observed. Also, the sensory evaluation of coconut milk samples indicated that the highest sensory acceptability was for samples containing intermediate amounts of coconut powder. Buttragacanthin gum only influenced the flavor and consistency of parameters. Finally, the sample consisted of 4. 28% coconut powder and 0. 15% tragacanthin gum as optimum sample with desirable physical, chemical and sensory properties.

Yazdi cake is one of the indigenous snacks of Iran that by adding some ingredients can improve its nutritional and textural properties. Green tea extract is high in antioxidants and have a health role. The aim of this study was to investigate the effect of green tea extract on physicochemical and sensory properties of Yazdi cake. In this study, green tea extract was added to Yazdi cake formulation at 0, 2. 5, 5 and 10% levels. Then the physicochemical properties (moisture, protein, fat, ash, fiber, carbohydrate, Specific weight for cake dough, cake volume, density, porosity, weight loss) and sensory analyze during storage at 2, 4 and 6 days intervals after baking, it was performed according to standard methods. All the prepared cakes containing different concentrations of extract had significant physico-chemical and sensory characteristics and were within the standard range. Observations showed that the addition of green tea extract in cake formulation decreased weight loss, moisture, porosity, density, brightness, ash and sensory scores and increased volume, fiber, fat, protein, carbohydrate and specific gravity. High levels of 5% green tea extract had a negative effect on the quality of the cake. Therefore, the addition of green tea extract at levels of 2. 5 and 5% produced an acceptable product cake. Finally, optimization of Yazdi cake formulation to produce a useful product using the investigated characteristics and limits indicated that 2/5% of green tea extract is the most suitable enrichment for Yazdi cake, in which the percent extract there was no adverse change in the physicochemical and sensory properties of the cake.

Biodegradable packaging based on natural ingredients has recently attracted an increasing interest from researchers. In this research different concentrations of persian gum (PG) (0, 0. 25, 0. 5, 0. 75 and 1%) with different concentrations of carboxymethyl cellulose (CMC) (1 and 1. 5%) were used to optimize biodegradable film production. For optimization of film production, maximum transparency value, contact angle, tensile strength, strain at break and minimum solubility, swelling and water vapor permeability were calculated. The results of the model showed that the effect of carboxymethyl cellulose and persian gum on all responses were significant (P <0. 05) and increasing the percentage of carboxymethyl cellulose and persian gum increased solubility, swelling, tensile strength and contact angle and decreased moisture content, water vapor permeability and transparency value. Both the predictive modelling and experimental results confirmed the carboxymethyl cellulose at 1. 5% and the persian gum at 0. 65% may provide the best result.

Oils and fats under the influence of several factors such as oxygen, light, heat, metal ions and enzyme are oxidized. Use of synthetic antioxidants due to the possibility of toxicity and carcinogenicity, has been under questioned. The aim of this study was to optimize the extraction conditions of Ajowan seed extracts and evaluate their antioxidant properties. In this study Ajowan seed under different concentration of solvents (water and ethanol in 0, 50 and 100% concentration), extraction time (0. 25, 12 and 24 hours) and different temperatures (20, 50, 80 ° C) were prepared. The optimal extraction conditions were defined by response surface methods and extraction was performed at the optimum condition. Then different concentrations (0. 2, 0. 4 and 0. 6%) of optimum extracts were prepared and added to the non-containing antioxidant soybean oil. All treatments were kept under 90 ° C for 5 days. Acidic value, peroxide value and thiobarbituric acid (TBA) were performed on each treatment in every day. Data analysis showed that addition of water to the solvent increased phenolic compounds extracts and antioxidant activity. According to the results of the thermal stability of soybean oil, the best results were related to BHT and other higher concentrations of ethanolic extracts. The results of the present study showed that the ethanolic extracts of Ajowan seed can be used as natural antioxidants in the formulation of edible oils.

The application of probiotic starter cultures in fermented products is expanding in different communities. The genetic variation makes the effects of these bacteria different and unpredictable in different human societies. Therefore, the safety control and evaluation of their non-pathogenicity is of great importance and monitoring centers are required to closely monitor the safety of the bacteria used in food products. In this study, two strains of Lactobacillus isolated from dairy products of Ardabil (Heyran mountain road villages) and Khuzestan province (Behbahan city) in Iran were identified based on the biochemical and molecular properties through sequence analysis of 16S rRNA gene. Then, their safety was examined based on the international guidelines, especially the European Union standard. The two identified strains included Lactobacillus fermentum (PTCC 1929) and Lactobacillus helveticus (PTCC 1930). The results showed the lack of gelatinase enzyme, inability of blood hemolysis, inability of amino acids decarboxylation and the lack of genes responsible for the invasive characteristics of pathogenic microorganisms including gelE, efaAfm, efaAfs, agg, ace, cylM, cylA, cylB. In addition, the results showed the sensitivity of both isolates to Penicillin, Ampicillin, Rifampicin and Tetracycline, and their resistance to Kanamycin and Ciprofloxacin. Lactobacillus fermentum was resistant to vancomycin, whereas Lactobacillus helveticus was susceptible to it. Since cases of antibiotic resistance are inherent according to scientific reports, the obtained results confirmed the potential application of these two isolated strains as starter in the fermented dairy products. It also confirmed the necessity of using safety assessment procedures for probiotic bacteria.

Meat is prone to contamination and spoilage due to its composition and production. Therefore, in order to extend its shelf life, the use of antioxidant and antimicrobial compounds has always been the focus of researchers' attention. The present study was conducted to evaluate effects of edible chitosan (2%) coating containing Cuminum cyminum essential oil (1%) on the shelf-life of meat in modified atmosphere packaging at refrigerated storage. The meat samples were separated into three groups uncoated (control), treated with chitosan coated without Cuminum cyminum essential oil and immersed in chitosan coated with Cuminum cyminum essential oil. Then Samples were packed in MAP (80% O2 and 20% CO2) conditions and stored at 4° C up to 21 days and evaluated periodically (on days 0, 3, 6, 9, 12, 15, 18 and 21) for microbiological (Total microbial counts, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. ) and chemical (pH, TBA and TVN) characteristics. Microbial analysis indicated that coating had significant influence (p<0. 001) on reduction of increasing trends of Total microbial counts, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. bacteria. From the aspects of chemical factors, the containing chitosan coating groups showed lower pH, TBA and TVN than those without coating. According to the results, chitosan coating significantly improved (P<0. 05) quality of samples. This study also indicated that the effect of chitosan containing Cuminum cyminum essential oil on samples was to retain their good quality characteristics and extend the shelf life during refrigerated storage, which was supported by the results of microbiological, chemical, and sensorial properties.

There is a growing interest in bioactive packaging systems due to their potential for the extended shelf life of food products. In this way, to produce probiotic nanocomposite whey protein isolatepolydextrose film containing cellulose nanofiber and Lactobacillus plantarum probiotic bacteria and evaluation of its antimicrobial effect on beef shelf life during storage time, different concentrations of polydextrose (0, 10 and 20 wt / wt% whey protein isolate) and cellulose nanofiber (0, 2. 5 and 5 wt / wt% whey protein isolate) were used for film preparation. Effect of variables on physical properties of the film (thickness, moisture absorption, water contact angle, and color properties) and effect of optimal film antimicrobial properties on enhancing the beef shelf-life during 8-day storage time in refrigerated conditions was examined. The results showed compatibility between the protein matrix of whey protein isolate, cellulose nanofiber and polydextrose. The use of polydextrose and cellulose nanofiber had a significant effect on increasing the film thickness, water contact angle, color changes and decreased the moisture absorption of the film. The results of covering the meat samples with the optimum film indicated a significant decrease in the growth of aerobic mesophilic bacteria, psychrotrophic and coliform bacteria during storage time. Finally, the results showed that the application of cellulose nanofiber and polydextrose in the film produced from whey protein isolate could improve the shelf-life of beef compared to the uncovered meat sample by creating a bioactive food packaging.

Kaymak or Sarshir, a traditional dairy product, is served in Iranian breakfast. The aim of this study was to investigate the fatty acids profile, physicochemical properties (texture, color, pH, acidity, the content of dry matter, fat and protein) and organoleptic aspects of Gilanvand and Dalirankaymaks in comparison to the heavy cream. To study more closely the texture and appearance differences of these products, scanning electron microscope (SEM) images were also prepared. The obtained results showed that the contents of fat and dry matter in heavy cream were higher than the kaymaks; however, Gilanvandkaymak had the highest protein content, acidity, and b*-value. Based on the study of the fatty acids profile, palmitic acid and cis-oleic acid were recognized as the most dominated saturated and unsaturated fatty acids, respectively. Microstructural analysis of SEM revealed that the structure of the protein in the fat field was compact, irregular and abundant in Gilanvandkaymak which influenced the product properties. The hardness, gumminess, and adhesiveness of the heavy cream were highest in comparison to the kaymaks. The Gilamvandkaymak obtained higher scores in evaluating the taste and total acceptance. In conclusion, it can be mentioned that the Gilamvandkaymak will have high potential in marketability by considering its higher protein content as well as total acceptance.

There are different methods for the preparation of infusions that can affect the properties of these infusions. The usual method for preparing of infusion is a maceration method that is made using boiling water and a filter. The aim of this study was to prepare marjoram infusion and evaluate the effect of the method of maceration and ultrasonic for different times (5 and 15 min) on phenolic, compounds, free-radical scavenging capacity (DPPH) and heavy metals (arsenic, lead and Cadmium) in the form of a completely randomized design. The results of data analysis obtained from the experiment showed that the preparation method of infusion had a significant effect on all the parameters of the study. The results showed that the amount of phenolic compounds, free-radical scavenging capacity (DPPH) and heavy metals (arsenic, lead and Cadmium) increased by increasing the time of both processes (ultrasound and maceration). On the other hand, the use of ultrasound waves was found to increase the usefulness of the compounds and also the heavy metals in the marjoram infusion. The total amount of heavy metals measured in this study was less than the standard defined for heavy metals for plant and fruit infusions. Finally, according to the results of this research, it can be stated that using 15 min ultrasound was the best method for making marjoram infusion.

Due to the extensive use of chemical preservatives to increase the shelf life of foods and the prevalence of colorectal cancer, the demand for natural and safe pharmaceuticals and preservatives has increased. Thus, this study aimed to evaluate the antioxidant and cytotoxic potentials of Foeniculum vulgare essential oil, which has vast applications in the traditional medicine. In this study, the essential oil of F. vulgare was extracted by hydrodistillation method and its chemical constituents were identified quantitatively and tentatively using gas chromatography coupled to mass spectrometry and fourier transform infrared spectroscopy. The total phenol and flavonoid contents of the essential oil and its antioxidant activity (DPPH and ABTS free radicals scavenging activity and β carotene/linoleic acid bleaching inhibition) were also investigated. The cytotoxic effect of F. vulgare essential oil was evaluated on colon cancer cell lines (HT29) using MTT assay. Anethole (75. 61%) was the main chemical compound of F. vulgare essential oil and its absorption peaks were appeared at 1244 and 840 cm. The total phenol and flavonoid contents of F. vulgare essential oil were 12. 87 mg GAE/g and 39. 67 mg QE/g, respectively. The antioxidant capacity of the essential oil, based on DPPH radical scavenging activity, ABTS radical scavenging activity, and β-carotene/linoleic acid bleaching inhibition, were 26. 68, 39. 57, and 32. 38%, respectively. The cytotoxic effect of the essential oil on the colon cancer cells was depended on its concentration. The F. vulgare essential oil could be used as a natural compound to inhibit the oxidation of foods and the prevalence of colorectal cancers.

Mayonnaise is a kind of oil emulsion in water that contains high levels of fat that cause cardiovascular disease in consumers. Therefore consumers tend to consume of low-fat mayonnaise. Therefore, in this study, the possibility of using nanoemulsions of Cordia myxal extract as fat substitute in mayonnaise was investigated. Fat was reduced in 25, 50, 75 and 100% in mayonnaise and it was replaced by 100 ppm and 400 ppm nanoemulsions of Cordia myxal extract. The results of the tests were analyzed by completely randomized design at the 5% probability level. The size of nanoemulsion droplets was determined as the mean 68. 7 ± 38. 3. The results showed that pH and acidity showed no significant difference between treated and control samples. Fat content in all samples was significantly lower than control, but moisture content and acidity of low-fat mayonnaise samples were significantly higher than control (P≤ 0. 05). Physical and thermal stability of all samples was significantly higher than control. In the colorimetric test (∆ E), all samples of low-fat mayonnaise had a significant increase compared to the control. In the sensory evaluation the highest score was given to the control sample in terms of overall acceptance, In terms of texture characteristics, the highest hardness and adhesiveness was observed in the sample that had a 25% decreased fat and contained 100 ppm nanoemulsions of Cordia myxal extract. This study showed that nanoemulsions of Cordia myxal extract at levels of reduced fat (25% and 50%) by adding nanoemulsions of Cordia myxal extract at two levels of 100 and 400 ppm have good potential for use in formulation of low-fat mayonnaise as a fat substitute.

Today, pectin is widely used as gelling agent and stabilizer in the food industry. The present study, pectin extraction from dried powder of peel and cap of pumpkin was performed in two different acidc and water solvents method. Finally, the samples that showed the highest pectin yield in each extraction method was selected for further experiments. Then, galacturonic acid percentage, degree of estrification, emulsifier stability, emulsifier activity, viscosity and FT-IR spectroscopy were applied to selected methods. The highest yield in acidic solvent (pH=2. 5) in cap treatment of pumpkin (23. 03%) and water solvent (for 3 hours) in cap treatment of pumpkin (17%) in 90 ° C, 90 minutes and solvent to dry matter ratio 1: 30 ml/mg was determined. According to the results, The highest percentage of galactoronic acid in pectin extracted from the cap treatment was observed in solvent acidc. The highest amount of estrification degree, emulsifiers stability and activity in pectin extracted from the peel treatment was observed in solvent acidc. Pectin extracted from cap treatment showed higher viscosity than pectin peel treatment. The viscosity of all solutions was used in the shear rate (0. 05-200 r(s-1 )) constant, which indicates the flow index (n) equal to 1 and the Newtonian behavior of the solution.

Maintaining the nutritional quality and preserving pomegranate seeds is a major challenge due to the fast degradation of the texture, color and overall quality of pomegranate seeds. In order to investigate the freezing of coated pomegranate seeds with chitosan and determine its quality during freezing storage, an experiment was conducted, in a factorial arrangement in a completely randomized design with three replications. Factors were: chitosan at three levels (0, 1 and 2%), freezing temperature at two levels (-14 °-24 ° C) and time at 5 different storage times (14 days, 30 days, 60 days, 90 days, and 120 days). The highest tissue firmness was observed for 14 days of storage under both chitosan concentrations. Interaction of different levels of chitosan coating and time had an increasing effect on the color component changes, so that the most color changes in the brightness (L*), redness (a*), and yellowness (b*) was related to the use of chitosan coating 2%, were maintained at 60 days. The highest total soluble solids were related to 1% chitosan under 4 months of storage at-14° C. Maximum total acidity (1. 36 mg / L) was also attributed to coated pomegranate seeds during 120 days of storage under both freezing temperatures of-14° C and-24° C. The results of mean compares showed that the total phenol stability under freezing temperature was higher at-14° C and after 120 days of storage, more phenol content was observed in the seeds in-24 C. The overall results indicated a positive effect of chitosan on maintaining the quality of pomegranate seeds during freezing, and the freezing temperature of-24 ° C with decreasing color changes during storage, played an important role in reducing metabolic activity and reducing anthocyanin degradation and was effective in maintaining fruit quality.