فهرست مطالب فردین میر احمدی

The plant Allium ampeloprasum, belonging to the Liliaceae family, is an important source of antioxidant compounds. In this study, the anti-radical and antioxidant activities, as well as the determination of phenolic and flavonoid compounds in the aqueous and alcoholic extracts of this plant, were investigated. In this laboratory study, the aqueous and alcoholic extracts of Allium ampeloprasum were prepared by adding 50 grams of the plant and mixing it in a 1:5 ratio with distilled water or ethanol. The total phenolic and flavonoid content was determined by spectrophotometry, and the antioxidant activity of the plant at different concentrations was measured using the Cuprac method, DPPH free radical scavenging, and ferric reducing antioxidant power (FRAP) assay. Data analysis was performed using SAS software and one-way analysis of variance. Based on the results, the total phenolic content in the aqueous extract was 86.9859 and 23.4 micrograms of gallic acid per milliliter in the alcoholic extract. The total flavonoid content was 42.81 in the aqueous extract and 345.54 micrograms of quercetin per milliliter in the alcoholic extract. Additionally, the total antioxidant capacity in the aqueous extract was 0.2362 and 0.3876 in the alcoholic extract, and the Cuprac method reported 0.0747 in the aqueous extract and 0.1992 in the alcoholic extract. The ferric reducing antioxidant power was 0.1041 in the aqueous extract and 0.0248 in the alcoholic extract, while the DPPH radical scavenging activity was 73.18 in the aqueous extract and 72.95 in the alcoholic extract. According to the study results, Allium ampeloprasum is a good source of antioxidant compounds, and its consumption can reduce oxidative damages in the body and improve health. Moreover, after extraction and purification, it can be used in pharmaceutical and food industries.

In the present study, the effect of strawberry extract on some oxidative, inflammatory and cellular damage indices due to acute resistance exercise in non-athlete women was investigated.

Materials: 

14 healthy non-athlete girls in a randomized, double-blind, placebo-controlled, crossover study in two complementary and placebo conditions (height: 162.5 7 2.7, weight: 70.4 6 6.3, body mass index: 2/2) 26.7 ، 1, age: 24.7 3 3.5). Subjects took 350 mg twice daily for 14 days before a resistance training session with strawberry extract or placebo (maltodextrin) supplement. Serum blood samples were collected for total antioxidant capacity, malondialdehyde, reactive protein C and creatine kinase, before the supplementation period (baseline), before and after a session of acute resistance exercise.

Total antioxidant capacity in complementary conditions before resistance exercise and after resistance exercise was higher than before supplementation (p <0.05). Malondialdehyde levels were higher than complementary conditions in placebo conditions and in the stages before resistance exercise and after resistance exercise (p <0.05). C-reactive protein did not change significantly (p <0.05). Creatine kinase levels in placebo conditions were higher after resistance activity than before supplementation and before resistance activity (p <0.05).

The results of the present study showed that strawberry extract supplementation may play a role in reducing cellular oxidative stress and cell damage due to strenuous exercise.

Strawberry plays an important role in human health because of its micronutrients and natural antioxidant content. Increasing storage time and decreasing microbial processes, weight and volume, and eventually facilitating export, has bolded the need for drying this product. The most common drying method is sun drying. This technique requires large areas and lengthens the time to complete the process which is undesirable economically. Furthermore, the final product may be contaminated by dust and insects, and the exposure to solar radiation results in color deterioration. In order to improve the quality, traditional sun drying techniques can be replaced by a more rapid and efficient drying method such as hot-air drying. In recent years air impingement technology has got more attention in the field fruit slices drying due to high heat and mass transfer, decreasing drying time and increasing product quality. The objectives of this study were to investigate the effects of drying conditions on the drying kinetics and quality characteristics including the rehydration ratio of the strawberry slices in an air impingement jet dryer.

An air jet impingement dryer with controllable temperature, air velocity, and the relative nozzle-to-product distance (H/D) was used in this study. The experiments were conducted under different temperatures (45, 55, and 65°C), air velocities (6, 9, and 12 m s-1) and H/D ratios (4, 5, 6, 7, and 8). The initial moisture content, effective moisture diffusivity, activation energy, and rehydration ratio were evaluated.

The effects of drying temperature and air velocity on the moisture ratio and the drying rate are shown in Figs 2 and 3. As it can be seen, the moisture ratio of strawberry slices decreased with the increase of drying time. The analysis of variance for drying time indicated that increasing drying temperature and air velocity could reduce the drying time.  In addition, the effect of drying temperature on drying time was more significant than that of the air velocity.  It is clear that the drying rate decreased with moisture content. There was a rapid decrease in drying rate during the initial period and slow decrease at the later stages of the drying process. It is also found that the drying process generally took place in the falling rate period. It is observed that the moisture ratio decreased as H/D ratio fall. The response of drying time was affected significantly (p < 0.05) by H/D ratio. The effective moisture diffusivity increased with increasing drying temperature and air velocity. Based on the results reported in this study, the Wang and Singh model with the lowest Root Mean Square Error (RMSE=0.02) and the highest Coefficient of determination (R2=0.996) provided the best fit to describe the experimental drying data of strawberry slices. The statistical analysis shows that drying temperature and air velocity have significant (p < 0.01) effect on the rehydration ratio (RR) of slices, while the interaction effect was not significant. The means comparison shows that the RR of dried slices decreased as drying temperature and air velocity rose. H/D ratio significantly (1%) affected rehydration ratio. The means comparisons shows that the rehydration ratio increased when H/D value varied from 4 to 8. Also, the results of color change represented that color change of dried samples decreased with increase of temperature and air velocity and increased with increase of the H/D ratio.

Conclusions:

 a) Increasing drying temperature and air velocity dropped the drying time. In addition, the effect of drying temperature on drying time was more significant than that of the air velocity. b) A constant rate period was not observed in drying of strawberry slices and the whole process of strawberry slices was carried out in the falling rate period. c) The moisture ratio decreased as H/D ratio dropped, which in turn resulted in saving drying times. d) The Wang and Singh model was found to be the best model to describe the drying kinetics of strawberry slices. e) The effective moisture diffusivity of strawberry slices ranged from 1.62×10-10 to 3.24×10-10 m2 s-1. f) The values of activation energy of strawberry slices were found to be 12.88, 15.055 and 16.746 kJ mol-1 for air velocities of 6, 9 and 12 m s-1, respectively. g) The rehydration ratio of dried slices dropped as the drying temperature and air velocity rose and increased with increase of the H/D ratio. h) The color change of dried samples decreased with the increase of temperature and air velocity and increased with the increase of the H/D ratio.

In general, excess plant and animal fats consumption leads to human health problmes. The aim of this study was to produce low-fat flavored cream with inulin as a fat substitute and date syrup as a sweetener. In this research, date syrup, in four levels of 0, 5, 7 and 10% was added as sweetener and inulin in four levels 0, 4, 6 and 8%. It was observed that with increasing inulin content in treatments, the apparent viscosity increased (p <0.05) and by increasing the amount of date syrup, the pH and viscosity of the samples are reduced (p <0.05). By adding inulin and date syrup, the amount of watering down decreased, but there was no significant difference between the samples. In the sensory evaluation, the best sample was the treatment with 7% date syrup and 4% inulin. The results of this study indicated that inulin and date syrup can be used to improve the physicochemical properties and taste in the low-fat cream.

Abstract Background and Clostridium perfringens is one of the pathogenic bacterial factors in animals and one of the important causes for food poisoning in human. The essence of P.atlanticaSubsp. Kurdica fruit or wild pistachios has been recognized as an anti- microbial compound against most of micro-ore anti-organisms. The purpose of this research is to determine the anti-microbial activity of the essence of P.atlanticaSubsp. Kurdica fruit on Clostridium perfringens microbe in laboratory environment and meat fabrications. Investigation in this research, anti-microbial effects of the essence of P.atlanticaSubsp. Kurdica fruit on Clostridium perfringens was evaluated via determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Ultimately, in third step of investigation, using the MBC from essence is considered as an anti-bacterial compound for food fabrications (hot dog and kielbasa) in order to reduce non-aerobic microbes especially Clostridium. SAS software method is used in form of two-factor factorial experiment based on a totally random plan in order to construct statistical evaluation. the results showed that MIC for Clostridium bacteria equals 250 milligrams per liter, ad MBC in P.atlanticaSubsp. Kurdica fruit essence for Clostridium bacteria was equal to 500 milligrams per liter. In concentration of 500 milligrams per liter of P.atlanticaSubsp. Kurdica fruit essence on Clostridium bacteria in samples of produced hot dogs had fatal effects. The P.atlanticaSubsp. Kurdica fruit essence on Clostridium has not only inhibition property but also anti-bacterial property and not only in laboratory, but also in samples of produced hot dogs, but does not have positive effects on its taste and this problem can be solved by purification and decolourization or it can be used as a drug or remedy for infection or poisoning resulted from it. Keywords: P.atlanticaSubsp. Kurdica fruit essence, minimum inhibitory concentration (MIC), hot dogs and sausages, organoleptic properties

Glycyrrhiza glabra L. (Licorice) is a perennial shrub growing in Mediterranean region and Asia and is widespread in Turkey, Italy and specially Iran. Licorice is a favorable herb used in food and medicinal remedies for thousands of years. This herb contains a variety of substances, among which glycyrrhizin is the most effective substance, giving a sweet taste to the root (30 to 50 times sweeter than sucrose). The roots of the study species were collected from the Kurdistan Agricultural Research and Education Center. All samples were dried and then powdered to extract the glycyrrhizin with different methods including modified Rosen, pre ultrasonic and post ultrasonic methods at 30 and 60 minutes, ultrasound frequencies of 35 and 100 kHz and a constant temperature of 60⁰C. The results showed that there were significant differences among the study treatments (P

Due to the ever-increasing of antibiotic-resistance microorganisms and the tendency towards the application of natural preservatives, in the present study the ethanolic extract of stalk portion of Kurdistan Gundelia tournefertti L. was extracted in rotary evaporator. The antibacterial effect (MIC and MBC) of the extract was investigated against Staphylococcus aureus and Escherichia coli. using agar dilution assay on Muller-Hinton agar. The experiment was conducted with 3 replicates and probity analysis of the data was analyzed using SAS 9.2 software.Result showed that both MIC and MBC for S. aureus was62.5 µg/ml. Moreover, the MBC and MIC values for E. coli were estimated at 31.25 µg/ml and 15.62 µg/ml, respectively.Since ethanolic extract of G. tournefertti was highly effectiveon indicator bacteria,it can be used in combination with the other preservatives to protect foods from foodborne organisms.

Staphylococcus aureus, Escherichia coli and Clostridium sporogenes can produce food poisoning and gastro enteritis in human beings. Alcoholic Essential oil of Bene tree exudates or wild pistachio (Pistacia atlantica subsp.kurdica) has known antimicrobial activity against most microorganisms. The aim of this study was to determine in-vitro antimicrobial activity of Bene tree essential oil exudates.

In this study, antibacterial effects of alcoholic essential oil of Bene tree exudates on Staphylococcus aureus (PTCC 1431), Escherichia coli (PTCC 1338) and Clostridium sporogenes (PTCC 1651) were examined three times, by filter paper disc diffusion method, broth dilution method, determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). For data analysis we used SPSS software and t-test.

On the basis of statistical results, inhibition zones of Staphylococcus aureus, Escherichia coli, each with concentration of 50mg/ml and Clostridium sporogenes with concentration of 120 mg/ml bacteria were 13.14±0.32, 11.16±0.4 and 8.8±0.3 respectively. Staphylococcus aureus was the most sensitive and Clostridium sporogenes was the most resistant bacteria to essential oil of Bene. Minimal inhibitory concentrations for Clostridium sporogenes, Escherichia coli and Staphylococcus aureus were 80, 5.5 and 0.6 mg/ml respectively and respective minimal bactericidal concentrations for Clostridium sporogenes, Escherichia coli and Staphylococcus aureus were determined 120, 80 and 20 mg/ml.

Alcoholic essential oil of Bene tree exudates exhibited not only inhibitory effect but also antibacterial effects on the Staphylococcus aureus (PTCC 1431), Escherichia coli (PTCC 1338) and Clostridium sporogenes (PTCC 1651). Considering the organoleptic effects of alcoholic essential oil of Bene tree, it can be used as a preservative.

The use of nitrogen fertilizers and low enzyme activity of nitrite and nitrate reductase in leaves of plants, causes the accumulation of nitrite and nitrate in leafy plants such as white cabbage (B.o var. alba).Nitrite is a highly carcinogenic substance therefore in this study changes in nitrite concentration during fermentation of fermented cabbage and spontaneous fermentation by inoculation of culture were examined. The strains used in fermented cabbage were Leu.meseneteriodes, subsp.mesenteroids PTCC 1563 and L. plantarum PTCC 1058 (Organization of Scientific and Industrial Research of Iran).The strains and their mixture as active culture, with equal numbers 5.6×106 cfu/gr were selected. Cabbage treatments consisted of inoculation with pure lactic starter (hemofermantative), inoculation with pure lactic starter (hetrofermantative), inoculation with a starter mix and cabbage not inoculated (control) were performed. Significant differences were recorded by the mean values of residual nitrites, pH, total number of lactic acid bacteria in the control samples (not inoculated) and inoculated samples (P<0.05).Residual nitrites in fermented cabbages by L. plantarum, Leu. mesentroides and mixed cultures were reduced up to 67.7%, 68.9%, 84.5% respectively, while it was 51.9% in the control treatment. The best treatment concering residual nitrite was the fermented cabbage by mixed culture. The best treatment concering the pH and the acidity levels was the cabbage inoculated by Leu. mesentroides.

Nitrite salts of sodium have been used traditionally in meat products as preservatives, antioxidant and color fixative agents. Nitrite is highly carcinogenic agent. The aim of this work was to study acid lactic bacteria inoculation effects on nitrite and load of bacterial reduction in sausages products. Three lactic acid bacteria strains (L. fermentum PTCC 1638, L. plantarum PTCC 1058, Leu. mesenteroides subsp mesenteroides PTCC 1563) were selected for considering of their nitrite reduction ability primarily. Two strains of them (L. fermentum, L. plantarum) and their mixture were evaluated as starter cultures in the production of sausage. Their density standardized with 0.05 Mac-Farland dilution in 600nm wave length by spectrophotometric method. Mentioned strains and their mixture with finally number of (108cfu/g farsh) inoculated to sausage containing 120 μg/g nitrite. During “Fermentation period” nitrite residual mean value: pH,acidity, total number of lactic acid bacteria, total number of mesophilic aerobic bacteria and total number of Enterobacteriacea were significantly different in compared to no inoculation treatments(control) (P<o.o5).Residual nitrite in fermented sausage by L. fermentum, L. plantarum and their mixture, was reduced to 65.8%, 75.4% and 68.3% respectively, while it was 60% in no inoculation treatment. Result revealed, there is no difference between total aerobic bacteria men values in fermented sausages, by L. fermentum and mixture starter cultures (P>0.05).

A group of the natural antioxidants is the polyphenols in green tea leave extracts (GTE). In this research، the extraction of antioxidants from the leaves was done with aqueous solution and then the extract was purified and finally dried and made into powder. Then the antioxidant effects of produced powder and α -tocopherol at 200 and 500 ppm، butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) at 100 and 200 ppm، and the combination synergistic effect of mixtures: 200 ppm GTE+500 ppm α -tocopherol، 500 ppm GTE+200 ppm BHA and 500 ppm GTE+200 ppm BHT in two types of sunflower oil (with and without citric acid as a chelator) at 50oC and time intervals of 0، 5، 8، 12 days were examined and compared for peroxide value (PV) and thiobarbituric acid (TBA) test. Results showed that the individually antioxidant effect of GTE at both concentrations was better than that of other antioxidants. Combination of GTE+BHT demonstrated antagonistic effect but no remarkable synergism or antagonisim was observed in other combinations.