نشریه نوآوری در علوم و فناوری غذایی
پیاپی 14 (زمستان 1391)

The aim of this study was to determine the effect of water and methanol extracts of Mint, Rosemary and Lavandula on Escherichia coli and Bacillus cereus growth as gram negative and positive bacteria indicators, respectively in five levels 0, 25, 50, 75 and 100 μg/ml. Calculating colonies was performed after 24 hours. Results indicated that the highest level (100 μg/ml) of Lavandula extract has been the most antibacterial effect (p<0.01). Also the methanol extracts of these plants is more effective than water extracts and Bacillus cereus distinguished more affected compare to Escherichia coli.

In 2002, acryalamide was discovered to form during the heat processes of starchy food by Swedish National Food Administration. Acrylamide has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer. Such reports are of great concern not only to consumers, but also to the authorities and the food industry. As breads have important role in the nutritional habit of Iranians and still have baked in traditional methods and techniques using direct heating processes. So determination of acrylamide content in different type of breads seems to be necessary.The main purpose of this study was comparison of acrylamide amount in different kind of breads in Kerman with LC\DAD method and determination of high resk bread. Chinese scientists shown that natural antioxidant in some herbs such as green tea, Bamboo leave, Rosemary, Thym, Liquorice significantly decrease the amount of acrylamide formation in heat processing of starchy food. In this study the effect of Rosemary extract in tree defferent density was investigated on formation of acrylamide in the high risk bread.

In this study, the physical properties of tree almond nuts and kernel (soft shell, and hard shell) were evaluated as a function of moisture from 4.89% to 26.17%. The results showed that friction coefficient for soft shell tree almond was the higher that that for the hard shell one (p<0.05). Coefficients of friction of all experimental samples increased by an increase in moisture content. The maximum coefficient of friction, 0.682733, calculated on play wood for all types of tree almond's nut and kernel. However, the lowest coefficient of friction among all whole nut samples was for galvanized sheet iron (0.513833), and for all kernels was on glass (0.570568). The angle of repose in hard shell nut, 60.58092477ₒ, was the highest value among all tested samples (p<0.05).

Enterotoxigenic Staphylococcus aureus is still an important cause of foodborne intoxications worldwide and milk and dairy products are frequently contaminated with extrotoxigenic Staphylococcus aureus, which is often involved in Staphylococcal food poisoning. The aim of the present study was to investigate the presence of classical enterotoxins of S. aureus in raw cow, sheep, goat and camel milk that was produced in Fars province, Iran. For this purpose, 84 milk samples including cow (n= 35), sheep (n= 20), goat (n= 21) and camel (n= 8) were collected from bulk milk tanks of 35 milking farm during three seasons of fall, winter, and spring and tested for staphylococcal enterotoxins (SEs) presence by Enzyme-linked immunosorbent assay (ELISA) method. Out of 84 samples studied, 12 samples (14.2%) were positive for at least one SE. Of these, 3 were positive for SEA, 2 for SED, 2 for SEC, 2 for SEA+SED, 1 for A+C and 2 for SED+SEC. None of the samples was positive for SEB and SEE. Statistical evaluation showed that there were not significant differences (P>0.05) between the presence of SEs of raw milk samples tested in fall, winter, and spring. Further studies should be carried out to investigate the presence of these toxins in different foods and their roles in food poisoning.

In this research, drying of green bell peppers by hot air dryer at temperatures, 60, 70 and 80°c kinetic drying parameters were investigated. The results showed that the temperature 80°c has highest rate of drying and lowest time. Also increasing the temperature caused increasing the shrinkage and most shrinkages were observed in 80 centigrade. rehydration rate decrease when temperature increase and the highest rehydration rate observed in 60 centigrade due to the decreasing of destroying capillary tube. the result showed that increasing temperature increasing moisture dispersion and activation energy value was 34.577kj/mol. Modeling based on 11 standard mathematical models was fitted to the experimental data. And criteria for evaluating models Determination of Coefficient (R3), Root Mean Square Error (RMSE), Chi-square(X2), and Mean Bias Error (MBE) were analyzed. Survey results showed that the Approximation of diffusion Model for the drying at temperature of 60 and 80 and Verma. et al model at temperature of 70 stages of drying peppers make a better assessment. So this model to predict changes in humidity and high quality product with hot air dryer for drying green bell peppers was diagnosed.

To determine the method of utilization of sorghum in food industry, this project was aimed at finding proper method of peeling and milling of sorghum grain and study on effect of sorghum flour on properties of dough and sensory attributes of bread. Peeling was done by using dry and wet method and fractured grain in final product and the percentage of ash and were measured. In the second step, the mixtures of wheat flour (W) and sorghum flour (S) with the ratio of (W: S) 90:10, 85:15, 80:20 and 50:50 were prepared and then farinography and baking test as well as sensory characteristics were evaluated using Completely Randomized Design (CRD) with replications. The result showed that the wet peeling method was not suitable method for making bakery flour because of mixing the skin and grout of grain and low quality of flour. In dry method, according to minimum grain ash and broken grain as well, the treatment of peeling in toothed vertical cylinder with blowing system and processing time of 360s was selected as a better process. Study on the result of second step based on farinography and baking test shoed that the ratio of 90:10 had not significant (α>5%) effect on produced bread quality, but the ratio of 85:15 led to sifnificant (α>5%) reduction of bread quality; But according to feasibility of 10% replacement of sorghum in bread making, and possibility of improving the quality of bread by using additives and/or by using dough making method and baking method, to produce new product and improve the product variety, it can be recommended to use higher percentage of sorghum flour.

In this research, zucchini samples were soaked into different osmotic solution concentrations (sucrose 35%+sorbitol 5%, sucrose 35%+sorbitol 10% and sucrose 35%+sorbitol 15%) and at 5, 25 and 50℃ under ultrasound and non-ultrasound pertreatment. Water loss and solid gain were increased whereas moisture content was decreased for all samples during dehydration time. Water loss values were 35.75 and 31 (g/100g dry solid) at 5% sorbitol concentration and 40 and 35.42 (g/100g dry solid) for both samples of ultrasound and non-ultrasound treatment at 15% sorbitol concentration, respectively. These values indicated significant difference at α=1%. Furthermore, solid gain values were 9.33 and 5.08 (g/100g dry solid) for ultrasonicated and noultrasonicated samples at 5% sorbitol concentration and 12.58 and 6.17 (g/100g dry solid) at 15% sorbitol concentration, correspondingly.

The aim of this study was to investigate the antimicrobial effect of garlic and onion extracts against Escherichia coli and Staphylococcus aureus in gelatin film. In this study, results showed, the minimum bactericidal concentration (MBC) of garlic and onion extract against Ecoli and Staphylococcus aureus was 2, 4 and 6, 4 ml/10ml respectively. Antimicrobial activity of gelatin film containing 2, 4, 6 and 8 ml of garlic and onion extracts per 10 ml of gelatin was tested. The greatest zone of inhibition against Ecoli was observed at 8 ml of garlic extract (25/5mm). Onion extract at 6 and 8 ml concentration that incorporated in gelatin films showed only inhibition against Staphylococcus aureus. Onion and garlic extract did not showed any antimicrobial effect against Escherichia coli and Staphylococcus aureus respectively.

In this study to extract proteins from chickpea types desi(kaka variety) and kabuli(ILC_6262 variety) was used from isoelectric precipitation (IEP).so was used from pH:9.5, 1/10 ratio(chickpea powder/water) and 250c for chickpeas. Protein content were at ranges 20.52±0.24% for desi and 16.71±0.15% for kabuli chickpea, w/w. The protein extraction in IEP process was 62.7–73.7%, w/w. measurement of chickpea protein solubility brought under consideration that results showed maximum solubility in range of pH:1-3,7-10 and showed minimum solubility in range of pH:4-6. Results of Water Holding Capacity(WHC) showed range between 3.1-3.3(ml/g).In emulsifying activity properties had not significant between two chickpeas(P<0.05). Results were showed a range between 103-106% for foam provider property. Also were showed that chickpea proteins have desirable capacity for gel formation.

In this study, 138 raw milk samples were collected by simple random sampling method from milk collection centers of Amol town during every season of the year (2010). The samples were transferred to laboratory in refrigerator conditions. Then, the samples in broth culture enriching Campylobacter were placed in incubator for 48 hours under microaerophilic conditions at 42. Enriched cultures were transferred to the selected culture based on blood agar and were placed again under above – mentioned incubation conditions. Then, bacterium DNA was extracted from 1ml. enriched broth (using fast method of extraction). Tracking and identifying of campylobacter species was carried out through multiplex PCR using specific gene of species jejuni and coli. DNA ladder 100 pb was used as a size reference for PCR experiment. PCR product was identified for species jejuni with 160 pb and species coli with 894 bp by electrophoresis gel. In this study, of 138 samples in any season, C. jejuni and C. coli were specified 6.6% and 1.5%, 11.6% and 3.7%, 5.1% and 2.2%, 2.9% and 0.8%, in spring, summer, autumn, and winter, respectively. Results of this study showed that Campylobacter jejuni and coli incidences in raw milks of Amol town were the most in summer and the least in winter (p<0/05).

The importance of prebiotics, the indigestive compounds which selectively stimulate the growth and functioning of probiotic bacteria such as lactobacilli and bifidiobacters, is being increasingly notified. Inulin is one of the precious prebiotic compounds which is commercially extracted from perennial chicory plants. In Iran, chicory grows natively as an annual plant hence it cannot be commercially utilized for inulin extraction. The aim of this research was extraction of inulin from non-native chicory plant which was grown in Iran, along with comparing the extracted inulin with a commercial sample. Natural inulin was extracted from chicory stub by maceration with hot water, clarification and concentration of extract followed by ethanol precipitation. Inulin extracted from the biennial chicory showed a higher degree of polymerization compared to the control sample. Growth of Lactobacillus casei and Escherichia coli as probiotic and pathogenic bacteria was evaluated in the presence of 0, 1 or 2% inulin compared to the commercial inulin, glucose and fructose. Results from the spectrophotometric analysis as well as evaluating the bacterial growth and survival showed that 2% of inulin was more successful in enhancing the growth and cellular density of probiotic bacteria while the growth of E. coli was increased in presence of 2% glucose and fructose.

Pomegranate seed contains high nutritional valuable bioactive compounds that are considered as losses in pomegranate processing factories due to lack of suitable processing methods on it. So this research was conducted with the aims of recognition physical, chemical and thermal properties of Pomegranate seed oil. In order to measuring its physical, chemical characteristics, the classical methods were used. The results showed values for viscosity, refractive index, colorimeter index (Yellow/Red): 155centipoise, 1.5088-1.5095, 6.71 respectively. Besides predominant fatty acids were ponicic, linoleic and oleic. Tri acyl glicerols of Pomegranate seed oil were classified in 5 categories by ECN as of 36, 38, 40, 42 and equal or more than 44. The highest tri acyl glycerols were with ECN=36. Pomegranate seed oil contains phenol, tocol and esterol compounds as of 168.13, 425.995 and 598.7 milligrams per kilogram of oil respectively.Thermal properties of the Pomegranate seed oil and the amounts of the released or absorbed energies were measured by differential scanning calorimetery. There were different melting and soliding points in this oil that resulted of different tri acyl glycerols structures. Our results suggested that the Pomegranate seed oil, which have high nutrition properties, can be used in food and medical industries.