فهرست مطالب مریم اوتادی

In order to targeted delivery of probiotics for food and drug applications and their effectiveness in preventing and treating various diseases, designing effective systems in this field can be helpful. In this paper, a new system for targeted delivery of probiotics has been introduced. The objectives of this study included: the efficiency of anti-acid microgels coated by multilayer polyelectrolyte formulation of alginate-chitosan for survivability of probiotic bacteria in gastric and intestinal simulation conditions. Tow Strains of probiotic bacteria including Lactobacillus Rhamnosus and Lactobacillus Plantarum were encapsulated separately in alginate hydrogels and calcium carbonate as an antacid agent (to control pH under acidic conditions) and coated with double bilayer alginate-chitosan by LbL self-assembly technique. The results showed that ( in the presence of pepsin enzyme and at pH=1.8 and in the presence of pancreatin enzyme and at pH=6.8), the survivability of these bacteria increased significantly compared to lactobacillus Plantarum and Lactobacillus rhamnosus 6 log(cfu/g) and 2.5 log(cfu/g) respectively. The number of viable cells in both probiotic strains was higher than the acceptable therapeutic level. In general, these results showed that these microcapsules can be used in controlled delivery of probiotics as food supplements successfully.

Due to the risks of using synthetic preservatives such as nitrite and its salts in meat products, there have been some efforts to reduce these synthetic preservatives in food. This study aimed to investigate the replacement of part of nitrite in 55% sausage formulation based on the conventional formula of a manufacturer.

For this purpose, Samples were produced with 120 ppm nitrite and a combination of lettuce and Foeniculum vulgare powder in four formulas including T1 (90 ppm nitrite+ 30 ppm lettuce and fennel powder), T2 (60 ppm nitrite+ 60 ppm lettuce and fennel powder), T3 (30 ppm nitrite+ 90 ppm lettuce and fennel powder) and T4 (120 ppm lettuce and fennel powder) and a control sample with 120 ppm nitrite (without lettuce and fennel powder). Physicochemical sensory, and microbial properties were investigated during 30 days of refrigerated storage.

The lowest pH (2.75%) did observe in T1 treatment on the 30th day of the experiment (p<0.05). The lowest moisture content (56.52%) and ash (2.43%) related to the control treatment on the 30th day of the experiment (p<0.05). Application of 30, 60, 90, and 120 ppm levels of lettuce powder and fennel in the treatments showed a decrease of 17, 18, 16, and 24% in the nitrate content of the samples, respectively (p<0.05). The highest and lowest peroxide value was 1.15 meq O2/Kg for the control sample on the 30th day and 0.3 meq O2/Kg for the T4 sample on the first day of the experiment, respectively. Regarding thiobarbituric acid index, the highest and lowest values were for the control sample with 24 mg Malone Aldehyde / Kg on the twentieth day and 15.76 mg Malone Aldehyde / Kg for the T4 sample on the 30th day of the experiment, respectively (p <0.05). The bacterial growth rate is lower in treatments containing combination lettuce, Foeniculum vulgare powder, and nitrite but in general, an increasing trend in microbial load observed in all treatments during 30 days of storage (p<0.05), While Clostridium perfringens, coliform, mold, and yeast did not grow on the treatments for 30 days (P> 0.05). In the sensory evaluation of treatments, the lowest a * observed in T4 treatment. The highest and lowest b* related to T1 and T4 treatments, respectively, While the combination lettuce and Foeniculum vulgare powder did not show any effect on the L*. The results of the sensory evaluation showed that the addition of lettuce and Foeniculum vulgare powder up to 60 ppm had no effect on the taste and smell of the treatments and showed a decrease in the aroma score in the treatments with increasing combination powder. Finally, the results of this study showed the possibility of successful replacement of some nitrite (at least 60 ppm) with a combination of lettuce and fennel powder.

Nowadays, the industrial effluents contain mineral and organic hazardous materials such as phenols, heavy metals, and dyes, which are carcinogenic and poisonous compounds even at low concentrations. An increase in such components especially dyestuffs in the environment makes the remediation of these pollutants valuable. Toluidine Red is a pigment containing azo groups, which is invasively used in different industries. There are several chemical, physical, biological, optical, and combinational methods for different pollutant removal from the environment. In recent years, the bioremediation technique has been considerably developed as an effective method in pollutant removal. Therefore, the goal of this study was to optimize the Toluidine Red removal from the synthetic dyes wastewater by Halomonas strain D2 in static culture conditions. In this survey, optimization and variables’ effectiveness study was performed by the response surface methodology (RSM).

In this research, the effectiveness status of variables and optimum conditions were studied by the statistical approach of Design Expert V.7 software. Biodegradation of dye was investigated by 30 experiments according to the Central Composite Design (CCD) and RSM. According to previous related research performed by one factor at time (OFAT), the effects of four variables of dye concentration, NaCl salt concentration, pH, and temperature on bioremediation at 10-30 ppm, 2-10 %, 5.5-9.5 and 20-40 °C, respectively, were studied. Bioremediation experiments in the aqueous phase of the synthetic model effluent have been performed in shake flask scale and static culture condition in an incubator for 10 days. Then the analysis of the resulted data was performed by analysis of variance.

According to the results and analysis of variance, salt concentration and temperature are the most significantly effective variables on bioremediation in the studied range while pH and dye concentration were probably less significant. Furthermore, the interactive effect of dye concentration and pH, salt concentration and pH as well as salt concentration and temperature were in a 95% effectiveness possibility limit. On the other hand, the maximum dye removal was observed on the 10th day of the experiment with 62.4%. The optimum condition for bioremediation was observed at a pH of 8.5, the temperature of 35 °C, and salt and dye concentrations of 4% and 16.8 ppm, respectively. By RSM, a correlation of second order for dye removal percentage after 10 days was presented with R2 equal to 0.95. The average error of the proposed correlation and real experimental data was about 9.9%.

The second-order correlation proposed in this paper can effectively predict the different operational condition effects on removal of Toluidine Red by Halomonas strain D2 that is a useful bacterium in dye biodegradation. Comparing this survey with our previous study, which was about decolorization by Gb strain, shows that the optimum condition is different for each strain type. On the other hand, D2 strain performance was higher in the basic condition in comparison with strain Gb, however, in acidic conditions, the Gb strain’s performance was better.

The glucose-oxidase enzyme is widely used in industry. Glucose oxidase is an oxido-reductase enzyme that catalyses the oxidation of glucose to hydrogen peroxide and gluconic acid. In this study, the glucose oxidase enzyme, its structure and function, tragacanth polymer, different methods of enzyme immobilization and statistical modeling methods have been introduced. To investigate the enzyme activity of glucose oxidase using design of experiments (DOE) and response surface methodology (RSM), the results of 19 experiments, have been conducted in previous research, were used. For modeling and optimization of enzymatic activity, three variables of pH, temperature and immobilization time were selected and examined using the Design Expert software. Then, based on statistical modeling, a correlation was proposed that be able to determine the enzyme activity of the glucose oxidase. Using response surface methodology, maximum enzyme activity (1116.2 μmol/min) of the glucose oxidase was achieved at pH of 5.98, 37 ° C and 33.28 minutes. Finally we observed that our model results are accurately agreed with the experimental results.