Statistical optimization of xanthan gum production and influence of airflow rates in lab-scale fermentor

The present study was undertaken to investigate and optimize the possibility of xanthan gum production by Xanthomonas campestris PTCC1473 in 500ml shake flasks on the second grade date palm. Using an experimental response surface methodology [RSM] coupled with a central composite design [CCD], three major independent variables [nitrogen source, phosphor source and agitation rate] were evaluated for their individual and interactive effects on biomass and xanthan gum production in submerged fermentation. The optimum conditions selected for gum production were 3.15 g.l[-1] for nitrogen source, 5.03 g.l[-1] for phosphor source, and 394.8 rpm for agitation rate. Reconfirmation test was conducted, and the experimental value obtained for xanthan production under optimum conditions was about 6.7[+2]/-0.26 g.l[-1], which was close to 6.51 g.l[-1] as predicted by the model. A higher yield of biomass production was obtained at 13.74 g.l[-1] for nitrogen source, 4.66 g.l[-1] for phosphor source, and 387.42 rpm for agitation rate. In the next stage, scale-up from the shake flasks to the 1-L batch fermentors was carried. By using the optimum conditions for xanthan gum, the biomass and xanthan gum concentrations after 72h in three levels of air flow rate [0.5, 1 and 1.5 vvm] were obtained as 3.98, 5.31 and 6.04 g.l[-1],and 11.32, 15.16 and 16.84 g.l[-1], respectively. Overall, the second grade date palm seemed to exhibit promising properties that can open new pathways for the production of efficient and cost-effective xanthan gum

Common challenges in laboratory diagnosis and management of tuberculosis

The history of tuberculosis [TB] traces back to antiquity. Despite significant progress of various diagnostic methods and introduction of anti-tuberculosis drugs in past decades, TB is still a major worldwide health concern which leads annually to two million deaths, especially after the emergence of multidrug-resistant Mycobacterium TB and HIV co-infection. Presented here is a brief review of conventional and new TB diagnostic laboratory methods including their advantages and disadvantages as well as common challenges in diagnosis and management of TB

[ effect of flour extration rate, amount of asparaginase enzyme, and baking temperature and time on acrylamide formation in Sangak bread]

Acrylamide is a carcinogen element which is formed at temperatures higher than 120°C in the foods rich in carbohydrates, such as Sangak bread. At first, a series of confirmed mechanisms effective on the formation of acrylamide was determined: Free asparagine, glucose, fructose, maltose, and sucrose sugars in two kinds of dough made from two kinds of flour with the extraction rate of%82 and%93. Then, the effect of flour extration rate, enzyme asparaginase, temperature and time needed for baking, and interactions of effectual factors was studied on the formation of acrylamide in Sangak bread. The amount of acrylamide was determined by liquid chromatography tandem mass spectrometry [LC/MS/MS]. The data analysis was performed using Spss16, Minitab15, and Factorial test. A significant differenc was seen between average sugars other than sucrose in the two kinds of flour. Also, average acrylamid formed by principal factors affecting [flour extration rate, asparaginase enzyme, baking time and temperature] and reciprocal impact of the 2, 3, 4 factors showed a significant difference [p< 0/001]. The maximum of acrylamide formation from 72 treatments caused by the reciprocal impacts of the four factors was seen at the temperature of 352oC, baking time of 10 minutes, and flour with 93% extraction rate [without enzyme] of 60/30 [mg/kg] and the minimum of acrylamide formation was observed at the temperature of 241oC, baking time of 5 minutes and the flour with 82% extraction rate [with enzyme] of 13/07 mg/kg Sangak bread. The decrease of free asparagine by asparaginase enzyme indicated that glucose and fructose were the major sources of acrylamide formation in Sangak bread. The rate of acrylamide formation increased with the increase in flour extraction rate. This rate has direct relationship with baking time and temperature. Acrylamide formation can be minimized in the presence of asparaginase enzyme. Training the bakers not to toast the bread will result in the production of healthy Sangak bread

[ role of glucose-insulin-potassium therapy in the treatment of acute myocardial infarction: a review article]

Given the high prevalence and high mortality of cardiovascular disease, special attention should be paid to its treatment. Currently, the main treatment for ST-elevation myocardial infarction is restoring blood flow by dissolving the clot. In addition to this basic treatment, several pharmacologic agents have been studied during the past years. In this paper, clinical trials about glucose-insulin-potassium are discussed in addition to adjuvant treatment which has been suggested in recent years. All studies published in journals or presented at scientific conferences were searched in Elsevier, PubMed, Cochrane, and SID databases using relevant keywords. After quality control, eligible articles were included in the study. The results of this review article showed that studies on the effects of glucose-insulin-potassium treatment on mortality, cardiac enzyme levels, left ventricular ejection fraction, ST resolution, and inflammatory and oxidative biomarkers have been conflicting. But, generally, evidence from newer studies conducted on larger numbers of patients has shown ineffectiveness of glucose-insulin-potassium therapy. Currently, glucose-insulin-potassium therapy should not be recommended as an adjunct to thrombolytic therapy

Pediculosis capitis among primary school children and related risk factors in Urmia, the main city of west Azarbaijan, Iran

Pediculosis capitis is cosmopolitan health problem. In addition to its physical problems, its psychological effects especially on pupils are more important. This study was conducted to determine the Pediculosis capitis among primary school pupils and also find out the role of probable related risk factors in Urmia city, Iran 2010. 35 primary schools of Urmia City according to the defined clusters randomly have been selected during 2010. 2040 pupils [866 boys and 1174 girls] were included and examined individually and privately by experts. Presence of adult or immature lice or having nits less than 1 cm from the hair basis were defined as positive. Data about demographic features and factors which their effect should be determined were recorded in standard questionnaire. Data were analyzed by SPSS software with proper statistical test. Infestation was determined around 4%. Girls show significantly greater infestation. The availability of suitable warm water for bathing and hair length [separately in girls and boys] are significantly related to infestation load as well as infestation among different age groups. There was no significant relation between parent's education and job and infestation as well as bathing repetition per week and the kind of energy source which they have. Also there is no significant correlation between educational grades and head lice infestation. The head louse pediculosis is a health problem and remains a health threatening for school children. Effective risk factors should be determined carefully and regionally. Proper training plays a great role in order to prevent and control the problem

[Physico-chemical properties of some commercial lines of Iranian cultivated wheat flour and their effects on sensory attribute of biscuit]

Biscuits are the most common bakery product after bread in Iran and have a long shelf-life. The technological properties of Iranian wheats used to produce biscuits have not been investigated so far. The objective of this study was to investigate the physico-chemical properties of 20 Iranian wheat flours and the sensory properties of biscuits produced from them. Twenty Iranian wheat cultivars released by the Seed and Plant Improvement Institute [SPII], Karaj, Iran were studied. The wheat grains were milled using the Quadrumate Senior Mill. The physicochemical characteristics of the resulting flours were determined according to AACC [2000] methods. Biscuits were then baked from each flour and their organoleptic characteristics determined by trained panelists. The physical and chemical characteristics of the wheat flours differed significantly due to differences in genetic make-up and environmental factors. Sensory evaluation showed no significant differences between the colors and tastes of the biscuits. However, significant differences were found among them with regard to texture, shape and surface and overall acceptability. Further analysis of the data showed that the sensory characteristics of the biscuits were statistically negatively correlated with their protein and gluten contents, gluten index, and SDS sedimentation. Biscuits produced from Golestan, Moghan, Prishtaz, and Omid wheat cultivars had the highest quality and acceptability. The Moghan cultivar was found to give the highest yield of flour, so it is the most suitable cultivar for biscuit production

[Effects of barley beta -glucan on some rheological properties of wheat flour]

In the recent years, hydrocolloids have been the subject of much investigation as functional foods. In the present study beta-glucan was acid-extracted from barley and its effects on some rheological properties of wheat flour were investigated. Beta-glucanwas extracted from whole barley flour by the acid-extraction method. The total beta-glucan content of the extracted gum was determined using the Megazyme assay kit. The beta-glucan gum obtained was added to 3 samples of wheat flour, namley Nol, Setareh, and their Mix [50:50] flours at a level of 0.0%, 0.5%, or 1%. Doughs wer prepared from the what flour samples and theirrheological properties investigated. The SPSS software was used for data analysis. A completely randomized design was used for the experiment, the means being compared using the LSD test. The rheological behavior of beta-glucan-enriched doughs depended on flour quality and beta-glucan concentration. All the farinographic characteristics, specially water absorption, improved with increasing beta -glucan concentration. Extensograph results also showed that resistance to extension and extensibility increased with increasing beta -glucan concentration. The mix flour with 1% beta -glucan showed the best rheological properties [p<0.05]. In all the treatments addition of beta-glucan increased water absorption, dough resistance time, dough development time, extensibility, resistance to extension, and the surface area under the curve, and it decreased dough loss. Beta-glucan at1% level showed better rheological properties as compared to the 0.5% sample. Overall, considering all the chemical and rheological tests, it can be concluded that addition of 1% beta-glucan to mix flour results in the best treatment, although it is not the most effective

[Effects of salep, glycerol and sunflower oil on potato starch-based edible film]

Starch is one of the most abundant carbohydrate biopolymers with excellent film-forming properties. However, it has a poor resistance to water vapour and poor mechanical properties. The objective of this studt was to determine the effects of glycerol, oil and salep on the film properties of starch. Edible films based on mixtures of starch and salep [an Iranian gum] were prepared and their properties [mechanical and optical charactersitics, solubility, and water vapor permeability [WVP]] investigated. The mixtures were as follows: potato starch and salep [1-5%], potato and glycerol plasticizer [10-40%], and potato and sunflower oil [0-20%]. The results showed that the physical and mechanical properties of potato starch-based edible films were affected by the their contents of salep, glycerol, and sunflower oil. The salep gum increased tensile strength, elastic modulus, and C[asterisk], but reduced elongation at break and L[asterisk], while glycerol reduced tensile strength, elastic modulus, and UV transparency but increased elongation at break, L[asterisk], opacity, solubility and WVP. On the other hand, sunflower oil decreased elongation at break, tensile strength, elastic modulus, UV transparency, solubility, and water vapor permeability, but it increased opacity. Based on the findfings, it can be concluded that the optimum contents of salep, glycerol, and sunflower oil in potato starch-based edible films are 3%, 32%, and 8%, respectively

[Effects of flour type, freezing method, and storage time on the quality of Barbari bread made from frozen dough]

Studies show that huge amounts of bread are wasted in our country. One reason for this is the dough preparation process. The objective of this study was to explore the possibility of making bread from frozen dough to reduce bread wastage. Dough was prepared by the all-in method and frozen at -30°C to -35°C [fast freezing] or -18°C to -20°C [home freezer, slow freezing]. The frozen doughs were packed in two-layer polyethylene bags and stored at -18°C, defrosted after 24h, 48h, 72 h, and one week storage, and tested for extensographic characteristics. Barbari bread [a type of Iranian flat bread] was then made from the thawed dough samples and, after sensory evaluation, was stored for 1-4 d in two-layer polyethylene bags at ambient temperature, in order to do staling tests. Storage time significantly affected extensibility, resistance and the coefficient D [p<0.05]. The type of flour had no significant effect on extensibility, resistance, or energy changes. Sensory evaluation showed that shape and upper crust surface of the Barbari bread was significantly affected by the freezing method and flour type [p<0.05]. The data also showed that the lower crust surface, chewiness, aroma, and taste of the bread were statistically significantly associated with the flour type. The flour type, freezing method, and storage time had no significant effects on porosity, firmness, or staling. Fast-frozen dough prepared from strong flour can be an appropriate alternative for fresh dough for making Barbari bread

[Comparison of transplantation of human bone marrow mesenchymal stem cells and their derived neural like- progenitors to spinal cord injury rat model with injection]

The aim of the present study was to investigate transplantation of MSCs and their-derived Neural like progenitors [NLPs] into the spinal cord after injury and evaluate the survival, migration, differentiation properties of these cells in Rat spinal cord. NLPs were derived from MSCs [induced by bFGF [Fibroblast growth factor b], hEGF [Human Epidermal growth factor] and RA [Retinoic Acid]], and analyzed by flowcytometry and immuno fluorescence staining. MSCs and NLPs injected into model animals vein and collagen scaffold implanted into injured site. Behavioral testing was performed weekly for 5 weeks. Improvement of transplanted animals evaluated after 5 weeks. Unfortunately, Substantial changes were not observed among the rats after the transplantation. Immuno fluorescence staining analysis using human nuclei and BrdU antibodies confirmed survival and migration of hMSCs and NLPs into the injury site. Transplanted cells were found to adjacent segments located rostro-caudaly to the injury epicenter. Our findings indicate that hMSCs and NLPs couldn't facilitate recovery from spinal cord injury. However, these cells can express specific neuronal markers in injured site. There are many questions to be answered regarding this mechanism

History of cholera outbreaks in Iran during the 19[th] and 20[th] centuries

Cholera is an acute infectious disease with high mortality if left untreated. Historically, between the 19[th] and 20[th] centuries seven great pandemics of cholera occurred and worldwide, thousands of people died. Based on an old theory, cholera was considered an air-born disease and the emergence of its outbreaks were attributed to bad weather or miasma. However later in the 18[th] century, British physician John Snow [1813-1858] explained the association of a terrible cholera outbreak in London in 1849 to contamination of the drinking water supply with human excreta. Despite his finding, the causative agent of this dreaded illness was unidentified until later in the 19[th] century. In 1854, Filippo Pacini [1812-1883] an anatomist from Italy and then in 1883, Robert Koch [1843-1910] the German bacteriologist, discovered [vibrio cholerae] as the etiologic agent. During the major pandemics of cholera in 19[th] and 20[th] centuries this illness reached Iran and led to vast depopulation and a crucial impact on the country's socioeconomic status. Poor public health conditions, lack of a well-organized public health authority for implementing preventive and quarantine measures as well as Iran's specific geographic location were the main facilitating factors of the emergence of various epidemics, including cholera in Iran. The present paper briefly reviews the cholera outbreaks in Iran during the 19[th] and 20[th] centuries

Effect of ultrasound treatment on methylcellulose film properties and application of modified films in packaging of baguette bread

Edible films are generally defined as stand-alone thin layers of materials. They can form pouches, wraps, capsules, bags, or casings in many processes. Coatings are a particular form of films directly applied to the surface of foods. Films are generally prepared using biological polymers such as proteins, polysaccharides and lipids. Edible films have weak mechanical properties and water-vapor permeability [VWP], which can be improved by physicochemical modifications, e.g., ultrasound [US] treatment. Also, edible films, due to their biodegradable nature, can substitute [after appropriate physiochemical modifications] synthetic packaging for foods such as bread. Edible films of methylcellulose [MC] were prepared and the effects of US treatment [5-, 15-, 30- and 45-min durations] on their WVP, tensile strength [TS], and percentage elongation at break [E%] were determined. The effect of relative humidity [52, 57 and 75%] on WVP of the films was also determined. In addition, we also investigated the ability of applied wrappings to retard baguette bread staling by assessing the mechanical and organoleptic properties of breads. 15mm films containing 45% glycerol, treated with ultrasound waves for 5min [the best conditions], were selected and their effect on retarding bread baguette staling determined. Results showed a significant effect of ultrasound treatment on the MC films' WVP and mechanical properties. Moreover, relative humidity influenced WVP of the films. The MC films retarded staling of the bread samples only for one day. Ultrasound treatment can affect physical and mechanical properties of MC films to a large extent. Mechanical and organoleptic tests of bread indicate that the wrapping can retard staling of baguette bread only for one day. Thus, more research in needed to elucidate more light on the applicability of edible MC films in food packaging

Effects of D-Tagatose, inulin and stevia as sugar substitutes on the physical, chemical, rheological and sensory properties of dark chocolate

Chocolate is very popular among consumers of all ages. However, its consumption is limited for the obese and diabetic people due to its high energy and sucrose contents. Replacing sucrose by low digestible carbohydrates [LDC[s] will result in lowering its energy content and glycemic index, as well as in preventing tooth decay. The objective of the present study was to investigate the effects of replacing sucrose with 2 sugar substitutes, namely, D-tagatose and inulin, on the physical, chemical, rheological and sensory properties of dark chocolate. Inulin, a dietary fiber, and D-tagatose, a natural keto-hexose with a degree of sweetness similar to that of sucrose, were used as sucrose substitutes in dark chocolate formulas. The inulin:tagatose ratios in the mixtures were 100:0, 75:25, 50:50, 25:75, and 0:100. The physical, chemical, rheological, and sensory properties of chocolate samples prepared with the mixtures were determined. With a reduction in the inulin content and an increase in the tagatose content, the moisture contents of the chocolate samples decreased, while their a[w] increased. Increased D-tagatose resulted in increased hardness of the samples, the sample with 100% being the hardest, comparable to the control [sucrose] value. With regard to color indices, the least amounts of L*,a*,b*,c* and hue° were observed in chocolate samples with 100% inulin. Increasing D-tagatose led to increases in the color indices. The data also showed that reductions in inulin resulted in decreases in apparent and plastic viscosity and increases in ?0 and ?1. Thus, the lowest real and linear yield stresses were found to be in the sample with 100% inulin. The least apparent viscosity and the lowest plastic viscosity were observed in samples with 25% inulin-75% tagatose and 100% tagatose, respectively, with no significant difference with the control value. Overall acceptability of the chocolate samples increased with increasing the D-tagatose level. It can be concluded that in chocolate formula samples an inulin-tagatose ratio of 25%-75% and 100% tagatose are the best sucrose substitutes. As inulin is a dietetic fiber and tagatose and inulin have prebiotic properties, chocolate samples prepared using them are also desirable from a nutritional point of view and can be considered as functional foods

Effects of nanofilms packaging on organoleptic and microbial properties of bread

Thirty percent of agricultural products are annually wasted in Iran, 7 to 8 percent of which are due to improper packaging. In this study, the effects of seven types of nanofilms with low a permeability to oxygen and water vapor on organoleptic and microbial properties of bread were investigated. Voluminous [i.e., non-flat] bread samples packaged in nanofilms were stored at 5°C, 20°C and 35°C and tested for organoleptic properties on days 1, 3, 5, 7, 14, and 21of storage. Also microbial counts in the samples kept at the 3 temperatures were made on day 14. The three main factors affecting significantly staling of the bread samples were type of nanofilm, temperature, and length of storage. The effects of combination of each 2 factors were also statistically significant [p<0.01 and 0.05]. The lowest and highest amounts of staling on day 14 occurred in bread packaged in a 3% composite film [500ppm silver and 450ppm clay] and in the control package sample [with no nano-particles], respectively. The total microbial count decreased with increasing silver nano content of the film, such that the 2% [1000ppm] silver film had the lowest count. In addition, the control packaging at the 3 storage temperatures showed the highest counts for coliform and moulds. The lowest and highest counts for coliform and moulds were found in nano-packaging samples kept at 5°C and 35°C, respectively. In conclusion, the nano composite film with 3% nano-particles [SC3] was judged to be the best film due to lower cost and longer conservation of bread freshness

Occupational noise-induced hearing loss

Noise-induced hearing loss [NIHL] is a well-known entity in daily practice of otolaryngology. A wide variety of NIHLs are work-related. Occupational noise is the most common cause of NIHL in adults which is up to now considered incurable and the best approach to it is to utilize maximal protection. An effective noise exposure prevention program consists of identification of sources of noise and implementation of controlling measures and regulations at working environments as well as performing periodic audiologic evaluation of those who are working at noisy environments. The present paper, briefly reviews occupational NIHL mainly based on the related data available on PubMed up to early 2010

Lead poisoning in the world and Iran

Lead is a relatively ubiquitous heavy metal with particular features such as resistance to corrosion, high malleability and wide variety of industrial applications. In medicine, however, it is considered as a slow-acting toxic substance affecting multiple body systems, specifically functioning as a potent neurotoxin in the central nervous system. Lead poisoning may be acute or chronic and can be due to occupational or environmental exposures. The history of lead poisoning dates back to ancient times. The present paper briefly describes the worldwide historical accounts of lead poisoning with a special focus on Iran

[Gelatinization and staling of Iranian Lavash and Taftoon Breads]

Traditional Iranian flat breads have been widely produced and consumed all over the country and still play a major part in nutrition of the people. Starch gelatinization, retrogradation and staling of flat breads are topics of considerable interest to cereal chemists and baking technologists. This study aimed to investigate the processes of gelatinization, retrogradation, and staling of two types of Iranian flat breads, namely, Lavash and Taftoon. Three different flours with protein contents of 12.56%, 11.52%, 11.28% and extraction rates of 90%, 86% and 58%, respectively, were selected and, after chemical and rheological testing, used to bake Taftoon and Lavash breads. Starch gelatinization and retrogradation of the breads were quantified using Differential Scanning Calorimetry [DSC] after 1 and 3 days of storage. In the endothermic curves, the area under the curve, temperature at the start, and crystallization peak were used as the main criteria. Bread staling was determined using the shear test by Texture Profile Analyzer on days 1, 3, 5, and 7 of storage. Enthalpy, temperature at the start, and the crystallization peak were lower in Lavash bread, which is an indication of a slower rate of gelatinization and retrogradation in this type of bread due to the shorter time of the baking process. The data also show that Lavash bread is softer than Taftoon, but the staling rate [which shows the rate of firming during storage] is lower in Taftoon. Although the temperature in baking Lavash bread is higher, starch gelatinization cannot be completed due to the shorter time of the baking process and, consequently, its rate of crystallization is lower than in Taftoon. Therefore, retrogradation rate is lower in Lavash than in Taftoon. In addition, Lavash bread is thinner and softer than Taftoon and, therefore, it loses moisture faster and stales and dries more quickly

[Occurrence of ochratoxin A in rice sold in chain stores in Tehran, 2007]

Mycotoxin contamination of agriculture commodities is a serious concern as regards human and animal health. Rice is a staple food and one of the major carbohydrate sources in the diet of Iranian people. There are reports on the contamination of rice with mycotoxins such as aflatoxins, citrinin, deoxynivalenol, fumonisins B1 and B2, fusarenon-X, nivalenol, ochratoxin A, sterigmatocystin, and zearalenone. In the present study, 100 samples of rice sold in several branches of three of the main chain stores in Tehran, Iran were collected and analyzed for ochratoxin A [OTA]. Ochratoxin A was extracted from the samples with acetonitrile-water solvent and purified using the immunoaffinity column. HPLC with fluorescence detector was used to identify and measure the OTA, the detection and quantification limits were being 0.03 and 0.1 microg kg[-1] respectively. The OTA content in all the 100 imported and domestic rice samples was 69%. The mean and range of OTA were 1.37 +/- 5.72 and 0.15- 46.79 microg kg[-1], respectively. In the most samples OTA contamination were lower than the permitted thresholds in cereals according to the Institute of Standards and Industrial Research of Iran [ISIRI] standards. Considering the high contents of OTA in some of the rice samples on the one hand, and the high consumption of other foods contaminated with OTA on the other hand, the total intake of this toxic substance may exceed its Provisional Tolerable Daily Intake as determined by the Joint FAO/WHO Expert Committee on Food Additives. In order to control mycotoxin contaminations, taking pre- and post-harvest preventive measures [GAP, GHP, GSP, GMP and HACCP], as well as sharing experiences and collective effort of all the parties involved, are highly essential

[Efficiency and mechanism of action of hydrocolloids in preventing serum separation in Doogh]

Doogh is a kind of Iranian fermented dairy-based drink produced by adding water and salt to yoghurt. The major problem of this product is serum separation during storage, because of its low pH and aggregation of caseins. In the present study, the efficiency of some hydrocolloids in preventing serum separation as well as the stabilization mechanism of gum tragacanth-a local gum-were investigated. The effects of high-methoxyl pectin, tragacanth, and locust bean gum at different concentrations, individually and in combined forms, tragacanthin, and soybean soluble polysaccharides type M, on the stability of sour Doogh were investigated. In addition, the influence of gum tragacanth and locust bean gum on the stability of prebiotic Doogh [containing inulin] was also studied. In each case the duration of the study was 30 days. In order to elucidate the stabilization mechanism of gum tragacanth, the rheological properties, zeta potential, and microstructural characteristics of the stabilized Doogh samples were measured. According to our findings, tragacanthin, tragacanth and locust bean gum could inhibit serum separation for 30 days at a concentration of 0.1, 0.2 and 0.3%, respectively, while type M soybean soluble polysaccharides caused the stabilization at a concentration of 0.6% only for 6 days. Furthermore, combinations of gum tragacanth and locust bean gum were also effective in fully stabilizing Doogh [at a concentration of 0.15% and ratios of 80:20 and 50:50]. Inulin was not effective in stabilizing the sour Doogh samples. However, tragacanth and locust bean gums inhibited serum separation in prebiotic Doogh. Based on our findings, the most suitable rheological model for the control samples and the samples containing hydrocolloids were the Newtonian and Power law, respectively. Based on the results of this study, tragacanthin [the water-soluble part of gum tragacanth] seems to have a major role in stabilizing Doogh, probably by being adsorbed onto caseins [via electrostatic and steric repulsion]. On the other hand, bassorin [the water-insoluble part of gum tragacanth] may help stabilization by increasing viscosity. Therefore, gum tragacanth could be strongly recommended to be used as an adsorbing hydrocolloid in sour Doogh to inhibit serum separation

Efficiency of two iron microencapsulation techniques and their effects on some properties of pasteurized milk

Iron deficiency anemia is one of the most prevalent nutritional deficiencies in the world, as well as in Iran. A solution to this problem is fortification of foods with iron. In this study the possibility of milk fortification with microencapsulated iron was investigated. Two kinds of iron salts were microencapsulated by two novel methods, and the efficiencies and optimum conditions of the methods were compared. Then, milk fat oxidation, color indices and sensory characteristics of the fortified milks during storage for 3 days at 4oC were studied. Maximum efficiency [ME] was obtained with microcapsules with a ratio of iron ion-to-lipid [0.04] and a 5 molar% of Tween 80 in the liposome method [ME=85.5%], and at ratio of polyglycerol monostearate-to-iron salt of 15 to 1 in the F.A.E. method [ME=81.8%]. The minimum and maximum milk fat oxidation was observed in milks fortified with irons microencapsulated by F.A.E. and plain iron, respectively. From a sensorial point of view, there was no difference between milks fortified with iron microencapsulated by F.A.E. at a concentration of 7mg L-1 and control. Based on the findings of the present study, it can be concluded that the F.A.E. method, due to its simplicity, low cost, reasonableness, rapidness of the process, as well as higher stability of the microcapsules obtained, is an appropriate method for iron microencapsulation and fortification of pasteurized milk