Showing 32 results for Hojjati
Volume 2, Issue 1 (3-2014)
Abstract
The present study was conducted to determine the most appropriate tree species planted in the same ecological condition considering different variables at Darabkola forest, Mazandran Province. For this purpose, the success of planted species (maple, walnut, oak, pine, ash and elm) was assessed according to ninecriteria (soil nitrogen, soil phosphorus, soil potassium, leaf nitrogen, leaf phosphorus, leaf potassium, growth of diameter at breast, diameter at breast, H/D: height/diameter at breast height ratio). Analytical Hierarchy Process (AHP) was used to assess forest stands based on multiple criteria. Results showed that the maximum local priority of average annual growth, and leaf and soil nitrogenwere observed in pine stands, while the highest levels of phosphorus, potassium, and DBH were recorded for maple plantation. The calculated overall priority showed that based on concerning criteria, pine stand had higher growth and nutritional potential compare to the other stands, while other stands ranked as maple> elm> walnut>oak> ash. In conclusion, our findings from AHP suggested that the growth rate and nutrition ofpine and maple stands had more appropriate condition and efficiency than other stands and therefore found suitable for plantingin the study area.
Volume 2, Issue 3 (Summer 2022)
Abstract
Is Meinongian dicopulation justified? This is the main problem in this paper and our hypothesis is that Meinongian dicopulaism is counterintuitive. This is despite the rich list of syntactic and semantic features that Meinongian advocates of the double copula strategy attribute to the Meinongian (internal/encoding) mode of predication in contrast with the ordinary mode of predication. That is what we demonstrate in this paper. We argue that neither of the requirement that Meinongian formulas (i.e. those containing the Meinongian mode of predication) must be monadic; nor that they resist lambda abstraction; nor that logical closure governs them; nor that they can be incomplete (or inconsistent) and nor that they are no way contingent, may succeed in discriminating Meinongian from ordinary predications. Nonetheless, dicopulaistic semantics support our intuitive understanding of abstract objects as sets of properties only whence they embrace the counterintuitive conception of multiple denotations; of either copulas or (abstract) objects. Meinongian dicopulaism does not work.
Volume 7, Issue 4 (2-2018)
Abstract
Sustainable competitive advantage is crucial for organizations to survive in modern competitive environment. Since competitive advantage based on creativity is one of the most crucial factors for the survival of current organizations, factors influencing organizational creativity processes should be considered at organizational decision-making level. As many people and factors are involved in organizational creativity, decision-making becomes complex and unstructured real world issues with chaotic systems behavior, and consequently, hard operation research methods are not able to represent and solve it properly. Soft system methodology is one operation research’s methods applied to represent, structure and solve complex problems. Therefore, in this study, which is part of a PhD thesis, in addition to explaining the soft system methodology’s steps, we describe how the first four stages of the Checkland soft system methodology were applied to represent and structure the sustainable organizational creativity problem in detail. The conceptual model was created based on information gathered from experts and specialists in organized meetings and in-depth interviews who were exposed to data previously collected in reviewing individual, group and organizational creativity existing research results. At the end of these meetings and interviews we designed and developed a rich picture, root definitions, CATWOE analysis and the conceptual model for organizational creativity.
Volume 9, Issue 1 (Winter 2021)
Abstract
Aims: The present investigation aimed to study the effect of traditional-coal-mining on the spatial distribution pattern of soil properties in the Lavij-Forest located in the western part of the Hyrcanian area-North Iran.
Materials & Methods: After selecting a mine area, 16 plots (20×20m) were established by systematic-randomly (60×60m) in an area of 4 ha (200×200m-mine entrance placed at center) which was affected by coal-mining. An area adjacent to the mine (same site conditions) that was not affected by the mining activity considered as the control-area. In order to investigate soil Physio-chemical properties one sample was taken from the 0-10cm depth in each plot. To study the spatial-pattern of soil properties and lead and cadmium concentrations in the mining area, an area of 80×80m (the mine at the center) was considered and 80 soil samples were systematic-randomly taken (10m intervals). Geostatistical analysis was performed via Kriging method and GS+ software.
Findings: Results showed that mining had led to a significant decrease in soil moisture, pH, EC, nitrogen, and potassium level. Lead and cadmium concentrations were significantly higher in mine area (Pb: 10.97±0.30, Cd: 184.47±6.26mg.Kg-1) in comparison to control-area (Pb: 9.42±0.17, Cd: 131.71±15.77mg.Kg-1). The range value calculated for variograms of cadmium and lead was 210m. The kriged maps showed that the concentration of cadmium and lead near the mine crater was considerably higher in comparison with adjacent points.
Conclusion: The findings showed that coal mining activity had negative effects on the forest soil and it is necessary to consider reclamation of contaminated soil in these areas.
Volume 10, Issue 4 (Fall 2022)
Abstract
Aims: In the present study, groundwater quality evaluation for drinking and irrigation purposes in Tashk-Bakhtegan and Maharloo basin was investigated using the data from 420 observation wells.
Materials and Methods: To assess the suitability of groundwater in terms of hydrogeochemical parameters including potassium (K+), sodium (Na+), magnesium (Mg2+), calcium (Ca2+), chloride (Cl-), bicarbonate (HCO3-), sulfate (SO42-), Electrical conductivity (EC) and total soluble solids (TDS) for 420 monitoring wells in November 2017 (as a dry month) and May 2018 (as a wet month) and to calculate the Drinking Water Quality Index (DWQI) and Irrigation Water Quality Index (IWQI) were used.
Findings: The results showed that groundwater quality for drinking purpose varied widely across the basin, with the average DWQI value increasing from 238.83 in November 2017 to 249.79 in May 2018. IWQI results also indicated that in most areas, especially in the northern and southern parts of the basin, groundwater has moderate, high and severe limitations for agricultural activities in both months. The average value of IWQI increased from 47.67 in November, 2017 to 49.67 in May, 2018, indicating a slight increase in groundwater quality for agricultural use.
Conclusion: According to the obtained results, necessary precautions should be taken for groundwater before using it for different purposes, and the results of this study can be used in the planning and management of groundwater resources.
Volume 12, Issue 2 (Spring 2024)
Abstract
Abstract
Aims: Conversion of orchards and agricultural lands in urban areas to residential and commercial areas has made a wide range of hydrological changes in urban watersheds. The aim of this research is to provide an Urban Distributed Hydrological Balance Model (UDHBM) to investigate the urban runoff in some parts of Tehran, including Tajrish and Elahiye.
Methods: To reach this goal, at first, we broke down the runoff amount of upstream mountain and urban areas from measured values. The HEC-HMS Model has been used to determine the volume of net runoff and flood produced in metropolitan areas. The annual water balance model considering rainfall, evaporation and other necessary inputs, have been made after defining the amount of flood in metropolitan areas. In the next step, a sensitivity analysis has been carried out on the main factors affecting the model to obtain a better understanding of the behavior of the model by changing these factors.
Findings: Results of this sensitivity analysis showed that this model has the most sensitivity to the rain factor and soil hydraulic conductivity. The results of comparing estimated values and urban runoff observations show minimum root-mean-square error and maximum correlation coefficient of 89% with a significance level of 5%.
Conclusion: This means that the UDHBM model has a good ability to calculate the runoff volume based on water balance for each land usage including residential houses and buildings, streets, parks and urban green spaces.
Volume 13, Issue 0 (kongore 94- 2015)
Abstract
Volume 13, Issue 2 (1-2023)
Abstract
Background and Aim: Toxins produced by Clostridium botulinum are among the deadliest compounds known that cause botulism. Currently, the detection of BoNTs in food using bioassays on laboratory mice is a very sensitive method with a detection range of 7 to 20 pg.mL-1. However, bioassay for mice is time consuming. This method is fast, highly specific, and sensitive to experiments on mice. The aim of this study was to use the modified Sandwich ELISA method to detect BoNT/B toxin.
Materials and Methods: Recombinant 370 amino acid protein was expressed from the carboxyl terminus of the binding moiety of BoNT / B toxin with a molecular weight of 45 kDa as antigen and purified by Ni-NTA affinity chromatography. IgG antibodies were isolated from mouse and rabbit sera byG protein affinity chromatography. The sensitivity and specificity of the method designed to detect recombinant BoNT/B-HcC antigen and botulinum toxin type B were evaluated.
Results: Purified rat and rabbit antibody concentrations were 3 and 4.5 mg / ml serum, respectively. The minimum concentrations of detectable protein were determined by indirect ELISA with purified mouse and rabbit antibodies at 475 and 118 pg. By optimizing the sandwich ELISA method, at least 30 ng of recombinant BoNT/B-HcC antigen and146 pg of highly specific BoNT/B were detected.
Conclusion: sandwich ELISA method can be used for accurate and sensitive identification of Clostridium botulinum toxin type B. It is necessary to evaluate the effectiveness of this method in the future to detect botulinum toxin in environmental and food samples.
Volume 13, Issue 60 (0-0)
Abstract
Volume 16, Issue 2 (6-2016)
Abstract
The criteria for hydraulic design of flip buckets are based on the analytical and experimental methods obtained from physical models. Due to the importance of spillways in the safety of dams, these structures should be secure and highly efficient. In the present study, in order to increase the efficiency of the spillway, it has been attempted to optimally design wide- triangular flip bucket angle and chute spillway by applying genetic optimization method. To achieve the aforementioned objectives, firstly, the equations derived for dynamic pressure head on the flip bucket, the exit jet length, and scour depth have been used as the parameters of objective function (Hojjati, 1392). Thereafter, the weights of objective function parameters have been calibrated using data related to the spillway of Karoon 3 dam, and eventually triangular flip bucket angle and chute spillway have been designed with the help of genetic optimization algorithm. Taking into consideration the design parameters of Karoon 3 spillway, the spillway length and angle of triangular flip bucket were obtain as 17.4 meters and 30 degrees, respectively by means of genetic algorithm. However, their difference with , the spillway length and angle of triangular flip bucket of Karoon 3 dam has been obtained as 16% and 0%, respectively wich indicates that the genetic algorithm enjoys high potential for designing the aforementioned parameters. The width of downstream and deflector angle have been obtained 3.6 meters and 30 degrees, respectively with 70% decrease of discharge, 45.4% increase of Froude number, and consistency of the weights of objective function and flip bucket height. Also by assuming the weight constant, increasing Froude number and decreasing the width of spillway, the flow rate increases and results in the increase of the parameters used in the objective function. With the design parameters of Karoon 3 dam remaining constant and the significant increase of weights associated with the parameters of pressure and scour depth independently of each other; spillway width was designed very largely which is not cost-effective. As well, with the design parameters of Karoon 3 dam remaining constant and the decrease of weights associated with the exit jet length in a way that all the three parameters can be viewed equally effective in minimizing the objective function, maximum dynamic pressure and scour depth have been reduced as much as 7% and 16%, respectively; however, the jet length has undergone a reduction of 12% and its width has undergone an increase of 38% which is not fully desirable. As a result, the weight reduction of jet length is not cost effective due to the slight change of scour depth and the maximum increase of pressure on the flip bucket and also the big increase of spillway width. Therefore, it seems preferable that the effect of jet range parameter outweigh the other two parameters because increasing the jet range results in the further depreciation of flow energy which is the main focus of the ski jump dissipator construction.
Volume 16, Issue 4 (1-2016)
Abstract
Spillways have long been of practical importance to safety of dams, therefore these structures have to be built strong, reliable and highly efficient. Ski jump dissipator is one the flow energy dissipators which is applicable downstream of spillway chutes with velocity over 20 m/s. Flow over a flip-bucket is a two-phase and strongly turbulent flow. Turbulence modeling is one of the most limiting factors in accurate computer simulation of flows. By fixing the grid resolution and the discretization scheme, the difference of computation time is mainly attributed to the turbulence model. The choice of turbulence model depends on factors such as the physics encompassed in the flow, the level of accuracy required, the available computational resources, and the amount of time available for the simulation. It is a fact that no single turbulence model is universally accepted as being superior for all classes of problems.
The main purpose of the present study is numerical investigation of two-phase turbulent flow over a triangular flip-bucket to evaluate effects of different turbulence models in this type of flow. Hence, using FLUENT® software, two dimensional Reynolds averaged Navier-Stockes equations have been solved in unsteady state. Different turbulence models consist of k-ε, k-ω and RSM; have been used. To simulate two-phase flow, volume of fluid (VOF) method has been applied.
Standard k-ε and stress-omega RSM models with low-Reynolds number modifications have the best performance among the other turbulence models. In standard k-ε model when low-Reynolds number modification was activated, the effects of molecular viscosity were taken into account in near-wall regions. Therefore, in low-Reynolds number k-ε model, maximum dynamic pressure over the bucket was predicted more accurately in comparison with standard k-ε model. Regarding modification in strain-pressure terms in turbulence equations, effects of anisotropic Reynolds stress tensor were taken into account in stress-omega RSM model with low-Reynolds number modifications. Thus, compared to other turbulence models, numerical results of this model are in a better agreement with experimental results. Different k-ε models could not predict the jet trajectory after the bucket very well. Due to blending function in SST k-ω model, this turbulence model effectively blended the robust and accurate formulation of the k-ω model in near-wall regions with the free-stream independence of the k-ε model in the far field. In estimation of maximum dynamic pressure over the bucket, this model had a better performance than standard k-ω model and relatively similar results to k-ε model. In addition, SST k-ω model has shown the best prediction of the jet trajectory among other turbulence models. Eventually, with respect to computation cost and accuracy of results, SST k-ω turbulence model has been introduced as the most suitable turbulence model to predict the flow pattern of a triangular flip-bucket.
Volume 16, Issue 87 (5-2019)
Abstract
Volume 16, Issue 89 (7-2019)
Abstract
Kefir is a fermented dairy drink that are produced using kefir grain and has beneficial effects on human health. In this study, the effects of the addition of Inulin (0.5, 1, 1.5%) on the physicochemical (pH, acidity, viscosity, syneresis and color), microbial (lactic acid bacteria and yeast) and organoleptic characteristics of kefir prepared with buffalo milk were investigated during 15 days refrigerator storage. The results showed that with increase of inulin content, the acidity and viscosity of kefir samples increased during storage period, while with increasing inulin content, the syneresis of the samples decreased on the last day of storage. Inulin also increased the number of lactic acid bacteria in kefir, indicating that the inulin was a prebiotic, but did not affect yeast growth. In addition, inulin reduced the lightness of kefir. Sensory evaluation results showed that inulin reduced the odor, taste and texture and had a negative effect on the overall acceptance of samples. According to the findings of this study, although inulin increased the probiotic properties of kefir, it had a negative effect on syneresis and sensory attributes of kefir.
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Critical Reviews in Food Science and Nutrition 50(10):938-950. doi:http//:DOI: 10.1080/10408390903044081 [5] Yue, T.X., Chi, M., Song, C.Z., Liu, M.Y., Meng, J.F., Zhang, Z.W. and Li, M.H., (2015). Aroma characterization of Cabernet Sauvignon wine from the Plateau of Yunnan (China) with different altitudes using SPME-GC/MS. International Journal of Food Properties, 18(7):1584-1596. doi:http//:DOI: 10.1080/10942912.2014.923442 [6] Dan, T., Wang, D., Jin, R., Zhang, H., Zhou, T. and Sun, T., (2017). Characterization of volatile compounds in fermented milk using solid-phase microextraction methods coupled with gas chromatography-mass spectrometry. Journal of Dairy Science, 100(4):2488-2500. [7] Ligor, M., Jarmalaviciene, R., Szumski, M., Maruška, A. and Buszewski, B., (2008). Determination of volatile and non‐volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography. Journal of Separation Science, 31(14):2707-2713. doi:HTTP//:DOI 10.1002/jssc.200800183 [8] Ziadi, M., Wathelet, J.P., Marlier, M., Hamdi, M. and Thonart, P., (2008). Analysis of Volatile Compounds Produced by 2 Strains of Lactococcus lactis Isolated from Leben (Tunisian Fermented Milk) Using Solid‐Phase Microextraction‐Gas Chromatography. Journal of Food Science, 73(6):S247-S252. doi:http:doi: 10.1111/j.1750-3841.2008.00846.x [9] Koksoy, A. and Kilic, M., (2004). Use of hydrocolloids in textural stabilization of a yoghurt drink, ayran. Food Hydrocolloids., 18(4):593-600. doi:http//:doi:10.1016/j.foodhyd.2003.10.002 [10] Ozer, B., Kirmaci, H.A., Oztekin, S., Hayaloglu, A. and Atamer, M., (2007). Incorporation of microbial transglutaminase into non-fat yogurt production. International Dairy Journal, 17(3):199-207. doi:http//:doi:10.1016/j.idairyj.2006.02.007 [11] Şanli, T., Sezgin, E., Şenel, E. and Benli, M., (2013). The effect of transglutaminase on some physicochemical and sensory properties of the T urkish drinking yoghurt Ayran. International Journal of Dairy Technology, 66(3):410-416. doi:http//:doi: 10.1111/1471-0307.12045 [12] Romeih, E. and Walker, G., (2017). Recent advances on microbial transglutaminase and dairy application. Trends in Food Science and Technology, 62:133-140. doi:https://doi.org/10.1016/j.tifs.2017.02.015 [13] Kuraishi, C., Yamazaki, K. and Susa, Y., (2001). Transglutaminase: its utilization in the food industry. Food Reviews International, 17(2):221-246. [14] Oner, Z., Karahan, A., Aydemir, S. and Aloglu, H.S., (2008). Effect of transglutaminase on physicochemical properties of set-style yogurt. International Journal of Food Properties, 11(1):196-205. doi:https://doi.org/10.1080/10942910701286346 [15] 15. Shirkhani, M., Madadlou, A. and Khosrowshahi, A., (2015). Enzymatic Modification to Stabilize the Fermented Milk Drink, D oogh. Journal of Texture Studies, 46 (1):22-33. doi:https://doi.org/10.1111/jtxs.12107 [16] Vardjan, T., Mohar Lorbeg, P. and Čanžek Majhenič, A., (2018). Stability of prevailing lactobacilli and yeasts in kefir grains and kefir beverages during ten weeks of propagation. International journal of Dairy Technology, 71:51-60. [17] Walsh, A.M., Crispie, F., Kilcawley, K., O’Sullivan, O., O’Sullivan, MG., Claesson, M.J. and Cotter, P.D., (2016). Microbial succession and flavor production in the fermented dairy beverage kefir. Msystems, 1(5): e00052-00016. doi:http//:doi: 10.1111/1471-0307.12463 [18] Temiz, H. and Dağyıldız, K., (2017). Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow’s and Soymilk. Korean Journal for Food Science of Animal Resources, 37(4):606. doi:https://doi.org/10.5851/kosfa.2017.37.4.606 [19] Plessas, S., Bekatorou, A., Gallanagh, J., Nigam, P., Koutinas, A. and Psarianos, C., (2008). Evolution of aroma volatiles during storage of sourdough breads made by mixed cultures of Kluyveromyces marxianus and Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus helveticus. Food Chemistry, 107(2):883-889. doi:http//:doi:10.1016/j.foodchem.2007.09.010 [20] NIST. (2018). The National Institute of Standards and Technology, http://webbook.nist.gov/chemistry/. [21] De Kruif, C. and Tuinier, R., (2001). Polysaccharide protein interactions. Food hydrocolloids. 15(4-6):555-63. https://doi.org/10.1016/S0268-005X(01)00076-5 [22] Lucey, J.A., (2001). The relationship between rheological parameters and whey separation in milk gels. Food Hydrocolloids, 15(4-6):603-608. [23] Dickinson, E. and Lorient, D., (1996). Food macromolecules and colloids, TheRoyal Society of Chemistry, Cambridge. 328–339. [24] Walstra, P., (2003). Colloidal interactions. In: Walstra Peditor. Physical Chemistry of Foods. NewYork, Marcel Dekker Inc, 437– 476. [25] Hashemi, F.S., Gharibzahedi, S.M.T. and Hamishehkar, H., (2015). The effect of high methoxyl pectin and gellan including psyllium gel on Doogh stability. RSC Advances, 5(53):42346-423. doi:http//:DOI: 10.1039/c5ra03190g [26] Gharibzahedi, SMT. and Chronakis, IS., (2017). Crosslinking of milk proteins by microbial transglutaminase: utilization in functional yogurt products. Food Chemistry. 245:620-32. [27] Temiz, H. and Çakmak, E., (2018). The effect of microbial transglutaminase on probiotic fermented milk produced using a mixture of bovine milk and soy drink. International Journal of Dairy Technology, 71(4):906-920. doi:http//:doi: 10.1111/1471-0307.12521 [28] Aghlara, A., Mustafa, S., Manap, Y.A. and Mohamad, R., (2009). Characterization of headspace volatile flavor compounds formed during kefir production: Application of solid phase microextraction. International Journal of Food Properties, 12(4):808-818. doi:https://doi.org/10.1080/10942910802073189 [29] Guzel-Seydim, Z., Seydim, A. and Greene, A., (2000). Organic acids and volatile flavor components evolved during refrigerated storage of kefir. Journal of Dairy Science, 83(2):275-277. doi:https://doi.org/10.3168/jds.S0022-0302(00)74874-0 [30] Delgado, F.J., González-Crespo, J., Cava, R., García-Parra, J. and Ramírez, R., (2010). Characterisation by SPME–GC–MS of the volatile profile of a Spanish soft cheese PDO Torta del Casar during ripening. Food Chemistry, 118(1):182-189. doi:http//:doi:10.1016/j.foodchem.2009.04.081 [31] Güzel-Seydim, Z., Seydim, A., Greene, A. and Bodine, A., (2000). Determination of organic acids and volatile flavor substances in kefir during fermentation. Journal of Food composition and Analysis, 13(1):35-43. doi:https://doi.org/10.1006/jfca.1999.0842 [32] McSweeney, P.L. and Sousa, M.J., (2000). Biochemical pathways for the production of flavour compounds in cheeses during ripening: A review. Le Lait, 80(3):293-324. [33] Tamime, A.Y. and Robinson, R.K., (2007). Tamime and Robinson's yoghurt science and technology. 3rd edn. Woodhead Publishing Limited, Cambridge, England, Page:791. [34] Kilcawley, K., Faulkner, H., Clarke, H., O’Sullivan, M. and Kerry, J., (2018). Factors influencing the flavour of bovine milk and cheese from grass based versus non-grass based milk production systems. Foods, 7(3):37. [35] Solano‐Lopez, CE., Ji, T. and Alvarez, V.B., (2005). Volatile compounds and chemical changes in ultrapasteurized milk packaged in polyethylene terephthalate containers. Journal of Food Science, 70(6):c407-c412. [36] Wang, W., Zhang, L. and Li, Y., (2012). Production of volatile compounds in reconstituted milk reduced-fat cheese and the physicochemical properties as affected by exopolysaccharide-producing strain. Molecules, 17(12):14393-14408. doi:http//:doi:10.3390/molecules171214393 Study of adding microbial transglutaminase enzyme on the volatile compounds of traditional kefir beverage
Volume 16, Issue 91 (September 2019)
Abstract
Kefir is a kind of dairy drink with unique and exotic flavor that is traditionally produced from fermented milk with kefir grains included a mix of bacteria and yeasts. The phase separation during storage of kefir results in an unfavorable appearance, which is known as a defect, which can be controlled by making the cross- links between the milk proteins. In this research, the addition of the microbial transglutaminase enzyme (m-TG) to diminish the syneresis and its effect on the aromatic compounds of kefir was investigated during one-month storage at a refrigerated temperature using a solid phase microextraction method combined with a gas chromatography–mass spectrometer. The results showed that the adding of the m-TG to kefir significantly affected the syneresis of kefir and caused reduce in phase separation of kefir during storage. In total, 51 volatile compositions were isolated and identified from kefir samples using SPME-GC/MS. Most of the identified compounds include acids, alcohols, ketones, esters, and aldehydes, respectively. The results indicated that the storage time significantly affected the amount of all volatile compositions, so that some volatile compounds increased, while some volatile compounds decreased during storage. The m-TG had no effect the content of the volatile constituents except for alcohols. The findings of this study revealed that the total amounts of alcoholic and acidic compounds as well as carbon dioxide were increased during storage. On the other hand, total amounts of ketones, aldehydes and esters in kefir decreased during storage.Based on the findings of this study, it could be concluded that the use of m-TG without significant effect on the properties of aromatic compounds of kefir reduces its syneresis during storage.
Volume 17, Issue 99 (May 2020)
Abstract
Withania coagulans by two water and alcoholic extraction methods and the levels of 0.5, 1 and 1.5% of mentioned extracts contained plant proteinase were used in cheese making. The color parameters (brightness/L*, redness/a* and yellowness/b*), physicochemical properties (pH, moisture, fat, syneresis, total protein, soluble protein in water and in 12% TCA) and total acceptance of produced cheeses were compared with the control sample (prepared with commercial recombinant chymosin 0.5% WCE-cheese and its alcoholic form, an ultrafiltrated Iranian white cheese with an acceptable quality can be produced. However, commercial application of this extract in order to replacewith microbial rennet requires the risk assessment and to convince that the WCE is harmless for the human health.
Volume 17, Issue 100 (june 2020)
Abstract
The aim of this study was to extract and identify the volatile constituents of the essential oils of two species of citrus named Clementine and Mandarin and to investigate their antioxidant and antimicrobial potential. The compounds of the essential oils prepared by steam distillation were identified by gas chromatography-mass spectrometry (GC/MS). The antioxidant abilities of the essential oils were evaluated by ABTS and DPPH assays. The antimicrobial activities of the essential oils were investigated using the disc diffusion method against three Gram-positive (Staphylococcus aureus, Bacillus ceruse, and Bacillus subtilis) and two Gram-negative (Escherichia coli and Salmonella typhi) bacteria, a yeast (Candida albicans) and a fungus (Aspergillus niger) in comparison with the synthetic antibiotics.
The GC/MS results revealed that both essential oils were rich in hydrogenated monoterpens and limonene was the main compound in both essential oils. The highest percentage of DPPH and ABTS free radical scavenging was shown about 34.38% and 48.44%, respectively for Clementine essential oil and for Mandarin essential oil was 67.53% and 96.44%, respectively, at 900 ppm. The results showed that both essential oils inhibited the growth of the studied microorganisms and increasing the essential oil concentration, increased the zone of inhibition. The highest diameter of inhibition zone was observed in Candida albicans in both essential oils. The lowest inhibition zone for Clementine and Mandarin essential oils was also observed in Escherichia coli and Aspergillus niger, respectively. In general, the antifungal effect of both essential oils was more than their antibacterial effect. In conclusion, citrus peel essential oil could be suggested as a natural antioxidant and antimicrobial substance for use in food products.
Volume 17, Issue 108 (February 2021)
Abstract
In this research, the chemical characteristics of sesame, rapeseed and sunflower oils prepared in the presence of the customer were compared with similar industrial-refined samples during two months of storage. Their levels of iron, copper, arsenic, and lead were also measured. The average of moisture and sedimentation contents of refined oil samples and sesame and rapeseed oil samples prepared in the presence of the customer were in the range of Iranian standard, but the average values for sunflower oil samples prepared in the presence of the customer was higher than the Iranian standard limit. The mean of the refractive index, iodine, and saponification values of all samples was in the range of standard. The oxidative stability index of prepared oils in the presence of the customer was less than the standard. The mean acidity and peroxide value of all oil samples were in the standard range but increased significantly during storage so that all samples were unusable on the last day of storage. The anisidine value of all samples increased during storage so that the average of this index in oil samples prepared in the presence of the customer was not in the standard range from the 40th day of storage. The Totox index of all oil samples also increased during storage, which was higher in sunflower oil. The results also showed that the cox index of sunflower oil was higher than the others. The average of the studied metals in all oil samples was in the standard range. The findings of this study showed that industrial refined oils have better chemical properties and stability and it is suggested not to use oils prepared in the presence of the customer for frying and it is recommended that keep them for a short time to cooking purpose.
Volume 18, Issue 116 (October 2021)
Abstract
The effect of coriander seed essential oil on pH, moisture content, color indices (L*, a*, b*) and sensory characteristics (appearance, odor, and overall acceptability) of ground lamb mutton inoculated with Listeria innocua at various temperatures (4, 10, 25 and 37 °C) during 8 days storage were investigated. The effect of simultaneous day and temperature on the pH and moisture content of the samples was statistically significant (P<0.05). The highest and the lowest pH were observed on the 8th day and 37 °C in the sample containing essential oil (8.50±0.01) and 10 °C (5.85±0.01), respectively. In addition, the highest moisture content was recorded in the control sample on the first day (80.42±1.03%) and the lowest moisture content was observed in the sample containing essential oil on the 8th day at 37 °C (74.68±0.14%). The lightness (L) of the samples decreased during storage days and various temperatures and the highest lightness was on the first day and 4 °C (39.88±0.33) and the lowest brightness was observed to the control sample on the 8th day and 37 °C (8.70±0.06). The redness (a*) of the samples decreased during different days and temperatures so that the most redness was recorded on the first day and 4 °C (13.50±0.18) and the least redness was on the control sample on the 8th day and 37 ° C (-2.72±0.16). The results of the sensory evaluation showed that the appearance, odor, and overall acceptability of the samples decreased during the storage period and at different temperatures, but the samples containing essential oil and stored at a lower temperature were more acceptable. The findings of this study showed that the use of coriander seed essential oil preserves more of the characteristics of lamb at lower storage temperatures.
Volume 19, Issue 128 (October 2022)
Abstract
In this study, the antioxidant properties of nanoencapsulated rosemary leave extract in biopolymer basil (Ocimum basilicum) seed gum coating to control the oxidative stability of sunflower oil and sensorial properties of fried potato strips were studied. The rosemary leaves extract obtained by ultrasonic bath has phenolic compounds (174.4 ± 25.9 mg gallic acid / g extract) and flavonoid (78.30 ± 3.2 mg rutin / g extract). Antioxidant activity of DPPH free radical scavenging by IC50 was 98.16 ppm and oxidative stability at 200 ppm was 5.08 h. The average size of nanoparticles in basil seed gum coating was 284.2 nm. The peroxide value and thiobarbituric acid value of oil samples were calculated every 4 days (0, 4, 8, 12, 16, 20, and 24 days). The results showed that oil oxidation in samples containing nanoencapsulated rosemary extract was less than the control sample, oil containing free extract or TBHQ. At the end of 24 days of incubation period, the peroxide value of oil samples containing synthetic antioxidant TBHQ and oil samples containing nanoencapsulated rosemary extract in the basil seed gum were 23.4 and 17.80 mEq O2/ kg oil and thiobarbituric acid value were 0.16 and 0.06 mg of malondialdehyde/kg oil respectively. In addition, the higher sensorial score of color, odor, taste and overall acceptance was related to potato strips fried in oil containing nanoencapsulated rosemary extract. The results of this study suggest the use of nanoencapsulated rosemary extract in basil seed gum coating to increase shelf life of sunflower oil.
Volume 20, Issue 139 (September 2023)
Abstract
Ultrafiltrated (UF)-white cheese is almost a new generation of white-cheeses that is produced throughout ultrafiltration process. This cheese has a soft and spreadable texture and is distributed in the market after a short storage period. Lactulose is a prebiotic compound that in addition to its positive effect on the growth of probiotic bacteria, its beneficial health effects on human well-being is proved. In the current research, synbiotic cheese samples were produced with the usage of demineralized ultrafiltrated whey powder (DUWP) at 3 levels of 0, 1 and 2%, lactulose at 2 levels of 0 and 1%, and bifidobacterium bifidum as probiotic bacteria. Experimental samples were analyzed and tested for physicochemical analysis including pH, acidity, moisture, syneresis, fat, protein and soluble nitrogen to total nitrogen ratio (TSN/TN) during 60 days of storage at 4 ◦C. Results revealed that addition of DUWP and lactulose, except for protein, had significant effects on the other tested parameters. In addition, the time of storage period had noticeable impact on all the examined physicochemical properties (P<0.01). Based on the results of this study, it was found that the best UF-white synbiotic cheese could be produced with the usage of 1% of each DUWP and lactulose powders.
