abdolmajid maskooki

The diffusion process in the production of sugar is a determining process which affects the final quality of sugar. The pH of water which is used in this process is being controlled by adding sulphur dioxide gas to the water. In this research، the reason of corrosion of the sulphur dioxide gas transporter pipe to the diffusion water producer tank has been studied. In this way، the quantometery analysis of the base metal and weld zone، and X-ray diffraction analysis of the corrosion products has been applied. In addition، the corrosion rate of the base metal has been determined by the potentiodynamic polarisation technique at the temperatures between 50 t 70°C and also the DLEPR method has been used for the weld zone. The Results showed that the main reason of the corrosion of the pipe was the accumulation of the gas in the bottom of the pipe and the concentrated sulphur containing droplets which led to the localised corrosion ofthe pipe. Finally، changing the position of the branch pipes، shelving the pipe and changing the material are being suggested.

Extraction of bioactive materials from herbal plants may be interesting due to the growing trend of using herbal remedies instead of chemical ones. The aim of present study is to optimize the conditions of Berberine extraction from roots of Berberis Vulgaris by supercritical CO2. The dependency of Berberine extraction yield on extraction parameters, time and pressure, was studied by Response surface Methodology. The effective factors on the extraction yield and adequacy of proposed model was investigated according to the experimental data and statistical analysis. The correlation coefficient (R2 = 92.71 %) showed that about 93% of all alternatives can be explained by this experimental model. Pressure has the most influence on yield of extracted berberine and the interaction term of Time –Pressure is statistically significant on the berberine yield. Using supercritical CO2 method with pressure in the range of 300-400 bars and the time in the range of 40-75 minutes would lead to the maximum of berberine extraction (more than 400 μg/gr). Finally, yield of berberine extraction by SFE has been compared with traditional method (Soxhlet) and the strengths and weaknesses of this novel method have been considered.

Response surface methodology is a series of statistical techniques that can be used to design experiment, modeling and evaluating the effect of variables on the final obtained results and optimization of process conditions. In this research, optimization of the solvent extraction method of bioactive compounds from seedless barberry (Berberis vulgaris) was carried out using response surface methodology. Central composite design was employed with 13 treatments and 5 replications in central points and the effect of variable factors of temperature (50-70ºC) and extraction time (40-120 minutes). The amount of anthocyanin content, vitamin C, phenolic contents and antioxidant activities of extracted barberry were measured. Close agreement was found between experimental and predicted values of model. Effects of extraction temperature and time were found to be significant on all responses. According to these results, optimal extraction conditions were identified at 50 °C temperature for120 minutes. In this condition the maximum of phenolic compounds, anthocyanin, antioxidant activities and vitamin C contents were 585.725 mg GAE/100ml, 208.392 mg/l, 84.2603% and 1292.56 ppm respectively. The results showed that this methodology could be applied in the extraction of bioactive compounds in the natural product industry.

Baker's yeast is one of the most important additives for improving the bread quality and molasses is a commonly used source of sugars for producing baker's yeast. Nowadays, due to increasing the fermentation industries and limitation in suitable sources of sugars, the use of other carbohydrate sources may be considered.In this study, the possibility of baker's yeast production in three cultures of date, raisin, enzymatic hydrolyzed whey and molasses as a control was investigated.Also, the total amount of biomass, consumption of sugar, strength of levy and kinetic's parameters of growth in all mediums were determined.For enriching the mediums, yeast extract and pepton were used in order of 3.5 and 7%, respectively. Fermentation process carried out during 12 houres and the temperature is maintained constant to 30 C°. Agitation was of 150 turns per minutes and ventilation fixed at 2 V.V.M. According to the results,maximum and minimum amount of biomass were 93.33 and 81.35 g/l that they related to date and whey, respectively.The consumption of sugar except whey which had the lowest level, in other cultures had no significant difference.The highest yield (0.35g/g) is observed in date but the lowest yield was 0.32 g/g in whey. Also, the baker's yeast which growed in raisin extract, had the highest value in strength of levy.

The direct relation between high blood cholesterol and cardiovascular diseases has been proved. Food containing high amount of cholesterol such as meat and meat products, egg yolk, milk and dairy products can be elevated the cholesterol content in blood plasma. The possibility of cholesterol reduction in milk using beta cyclodextrin was investigated. In this research, various amounts of β- cyclodextrin (0, 0.5, 1 and 1.5 %) were mixed with raw (unhomogenized and unpasteurized) and homogenized milk at two temperature conditions of 8°C and 20 C. The cholesterol content of milk was measured for each treatment. The results that statistically were analyzed and showed that the cholesterol content of milk remarkably was decreased with increasing the amount of β- cyclodextrin, particularly in homogenized milk at 20 C. However, the reduction rate of cholesterol were decreased when extra β- cyclodextrin added due to its intermolecular reactions. The maximum cholesterol reduction was achieved when 1.5 % β- cyclodextrin added to homogenized milk at 20°C.

Attentions to use of ultrasound for cleaning of polymeric membranes are less thanone decade. In this experiment, the cleaning efficiencies of various frequencies of ultrasound in different membrane modules and the barrier effect of structural design and membrane module during cleaning process using ultrasound were evaluated. Three membranes, hollow fiber without module, flat sheet membrane including stainless steel and acrylic module and spiral wound with polyethylene modules applied during forward flushing cleaning process by ultra pure distilled water for 30 minutes after fouling by skimmed milk 1% using ultrasonic irradiation of 28, 45 and 100 kHz frequencies in constant intensity of 300W. The permeate flux and hydrodynamic resistance of new,fouled and cleaned membranes during sonication using various frequencies of ultrasound were determined separately. In this manner the cleaning efficiency of each treated membranes were calculated The data statistically analyzed using ANOVA table. The results showed that the most cleaning effects obtained in all tested membranes by various frequencies of ultrasound at first 5 minutes of cleaning process. The highest amounts of cleaning effect achieved in hollow fiber membrane using all tested frequencies especially in 28 kHz. The maximum cleaning efficiency achieved more than 95 percent for the first 5 minutes and may be due to lack of barrier such as holder or membrane support in the design of this membrane module. However, we observed the cleaning efficiency of 92 percent after 30 minutes in flat sheet membrane module using ultrasoundin28 kHz and the amounts of cleaning efficiencies in same conditions were lower than hollow fiber module. The other tested frequencies were not significant cleaning effects and stainless steel and acrylic holders in design of membrane module prevented to reach of sonic power to surfaces and pores of flat sheet membrane. The minimum ultrasound cleaning efficiency achieved in spiral wound membrane modules only 21 percent after 30 minutes ultrasonication using 28 kHz during forward flushing and it seems that only outside of membrane surfaces are affected. This is may be due to special design of membrane module and barrier effects of configuration and membrane holders.

Application of high isostatic pressure in biological and food researches has been extensively studied in the last decade. It has recently been proposed that high isostatic pressure might be applied to increasing both the activity and stability of several enzymes. In this research the enzymatic activity, CFU and morphological changes of commercial S.cerevisia under 0, 50, 75, 100, 125 and 150 MPa pressure at 5, 10, 15 minutes pressurization after 24 hours keeping in 4C° were studied. The results statistically analyzed and showed that 50 MPa pressure didn’t affected on yeast cells but increased the enzymatic activity in 75 and 100MPa pressure at 10 and15 minutes pressurization. In addition the images of scanning electron microscope (SEM) showed that despite of increasing activity of enzyme the structure of yeast cell walls changed and hollowed in 100MPa pressure. The enzymatic activity and CFU (1log.) significantly decreased in 125 and 150 MPa. Inactivation of yeasts and decreasing the enzymatic activity can be due to morphological changes of yeast cells by induced high pressure. The images of scanning electron microscope (SEM) after one month pressurization and keeping in 4C° showed that all of treated yeast cells were destroyed.