Journal of Food Technology and Nutrition
Year:2012 | Volume:9 | Issue:3 (35)|Papers Count:13

Introduction: Researchers have presented wide varieties of investigations concerned with the new sources of oils and fats due to higher demands to supply the increasing population of the world as well as the needs to concentrate on the quality of the oil produced. Fungi and yeasts might be able to produce high levels of fat and oil which in term of quality might be compared to vegetable and fish oils. The object of this investigation apart from the recognition of the role of fatty acids is the production of arachidonic acid and its extraction from Mortierella alpina as the main source.Materials and Methods: M. alpina was cultivated on different medium, with an initial pH of 6.5 and incubation period and temperature of 10 days at 12°C respectively.Results: Appropriate medium for Mortierella alpina containing (g/L) 144 glucose, 11 yeast extract, 3.8 KH2PO4, 0.5 MgSO4.7H2O, 3.4 NaNO3 where the mean rate of produced biomass and oil are 22.7 and 10.64 (g/L) respectively. Profiles of glucose show different gradients during cultivation time and according to this fact three regions might be considered for interpreting the profile. During the first two days of growth, M. alpine propagates rapidly but produced lowest concentration of oil. In the second region the rate of growth decreases while the production of oil increases dramatically. From the sixth to the tenth day both growth and production of oil is reduced.Conclusion: Production of oil by M. alpina is a two- phase procedure. With respect to oil production and the costs the 12 days incubation period might be regarded as an optimum and ideal incubation period.

Introduction: In diabetic patients, decreasing of serum glucose level and lipids is clinically important. In this study, the effects of Thymus vulgaris aqueous extract on the blood glucose and lipids in streptozotocin (STZ) induced diabetic rats was studied.Materials and Methods: In this experimental study, male Wistar rats weighting 200-250 gr were employed and maintained at 22±2ºC. The rats were divided into 5 groups and each consisted of 6 rats. Experimental groups were made diabetes by streptozotocin (STZ) (70 mg/kg i.p.). Three groups of rats were given aqueous extract (100, 200 and 400 mg/kg) for 21 consecutive days. After the treatment, blood samples were taken and serum glucose, triglyceride, total cholesterol, HDL-C, LDL-C, VLDL levels were measured by Enzymatic methods.Results: The results after 3 weeks indicated that serum glucose, total cholesterol, LDL-C, VLDL and triglyceride levels were increased (p<0.001) while HDL-C level was decreased (p<0.001) significantly in the diabetic group as compared to the control group. Treatment of diabetic ratswith Thymus vulgaris aqueous extract, caused a decrease in serum glucose, total cholesterol, LDL-C, VLDL and triglyceride levels (p<0.001) with an increase in HDL-C level (p<0.001).Conclusion: Treatment of diabetic rats with Thymus vulgaris aqueous extract not only decreased the level of serum glucose but also has beneficial effect on serum lipids.

Introduction: Mutton tallow as an important source of animal fat has considerable concentrations of saturated fatty acids and cholesterol that can cause coronary – heart diseases. The main object of this research is to investigate cholesterol distribution in different fractions of mutton tallow.Materials and Methods: The fat was extracted by dry rendering of sheep tail fat under vacuum, followed by solvent fractionation at 25, 15 and 5°C This resulted in two solid, one semisolid and one liquid fractions. Qualitative and quantitative tests consisting of fatty acid composition, melting point, iodine value, saponification value, nonsaponifiable matter content, free fatty acid content, induction period and colour measurements were carried out on tallow and its fractions.Results: The results indicated that tallow contains 101.74 mg/100 g cholesterol that has been reduced by 74.24, 59.81 and 47.29% in the first, second and the third fractions respectively, and has been increased by 45.68% in the fourth fraction relative to the original tallow.Conclusion: According to the results the amounts of cholesterol and unsaturated fatty acids in tallow fractions increased with decreasing the temperature of fractionation.

Introduction: Impurities of raw sugar beet have significant effects on sugar recovery and loss in the remaining molasses.Materials and Methods: More than 1000 random samples were taken from 28000 sugar beet receiving consignments during three months of operation at Orumieh Sugar Factory in 2008.Different impurities consisting of K, Na, and N along with sugar beet and resulting molasses were analyzed precisely by betlalyzer machine. The obtained data were used to predict sugar content of final molasses according to suggestive mathematical models of Reinefeld and Braunschwik.Additionally, the correlation coefficients of estimated and measured sucrose’s were figured out.Results: The results indicated that sucrose in sugar beet samples had a range of 8.4 – 20.5% with most frequency numbers of 15.5 – 16.7%. In addition, 69% of the sugar beet samples had a sugar range of 14.3 – 18.0%. The K and Na contents of sugar beet samples changed from 2.3 – 9.3 and 0.8 – 7.4 meq, respectively. Furthermore, the average value of non-protein nitrogen in sugar beet samples was 4.3 meq. According to Reinefeld and Braunschwik models the estimated sucrose in resultant molasses were 3.0 and 2.4% respectively.Conclusion: The average sugar content in the final molasses at the end of factory’s seasonal operation was 2.1%. While the Reinefeld model could predict the sugar content of final molasses with 45% deviation from its actual number, the Braunschwik model was able to predict this parameter in molasses with less than 15% deviation. It is much more appropriate to measure the Na, K, and N in receiving consignment of sugar beet and use Braunschwik model to predict the sugar loss in the final molasses.

Introduction: Sodium benzoate and potassium sorbate are used in sauces for controlling the microbial spoilage. These compound apart from their limited potentials as preservatives might have carcinogenic effects. Therefore, natural preservatives such as nisin and sodium diacetate might be considered as alternatives to these chemical preservatives.Materials and Methods: In this study the effects of different concentrations of nisin (150, 200, 250 ppm) with 750 ppm sodium diacetate (identical in all the samples) on the microbiological quality of French salad dressing were studied. The tests consisted of counts related to the total count, mold, yeast and lactobacillus, pH and sensory evaluations.Results: The results of microbial tests showed that the 200 and 250 ppm nisin with 750 ppm sodium diacetate exhibited good antimicrobial activities against the microorganisms studied.The number of microorganisms in the total count and pH value were in the range of national standard for salad dressings. The sensory evaluation test indicated that the samples containing 200 ppm nisin and 750 ppm sodium diacetate received the highest rate.Conclusion: According to the results, nisin and sodium diacetate could have inhibitory effect on the growth of microorganisms causing spoilage during storage of French salad dressing.

Introduction: Losses and wastes in the oil production and processing are considered the most important issues in the edible oil industries.Materials and Methods: In this research, experts from oil industries were provided with questionnaires concerned with processing stages and refining operations related to losses and wastes. The study took place in Tehran province. Analysis of variance using Minitabe software was employed to study the statistical analysis.Results: On the average 4.5 to 6.5% losses were estimated in each stage of refining operation in oil refineries located in Tehran province.Conclusion: Considering the amount of vegetable oil produced in 1387 (1, 400, 000 tons) and taking into account the quantity lost, approximately 68-101 thousand tons of oil is lost. If the average world crude oil price is estimated at 1000 dollars per ton a total of 68-101 million dollars is lost that is regarded quite considerable.

Introduction: Histamine poisoning, one of the most common sea food borne disease that is known worldwide, is caused by biogenic amines. Histamine, one of the biogenic amines, is present in spoiled Scombroid fish which contain usually high levels of free histidine.Measurement of histamine in food is very important and might be regarded as an indicator to freshness or spoilage. The aim of this study was the measurement of histamine in yellow fin tuna (Thunnus albacores) that were caught in Oman Sea waters in order to determine its spoilage and toxicity.Materials and Methods: Thirty fresh fish samples were obtained and the amounts of histamine were measured from the muscle around the gills by ELIZA method.Results: The obtained results indicated that the minimum, maximum and mean of histamine contents were 0.4, 12.8 and 1.9 ppm, respectively.Conclusion: Histamine levels were well below the recommended maximum value, which validates the recommended USFDA guidelines (<20ppm). Therefore, there is no histamine poisoning risk in the examined fish samples.

Introduction: One of the main objectives in cereal industry is to increase the shelf life of bread. Since Barbari bread is one of the most used traditional bread in Iran, therefore it is important to investigate how to retain its freshness.This study was conducted to evaluate kefir grains as baker’s yeast in Barbari bread and compare its quality with the traditional Barbari bread which is consumed in Iran.Materials and Methods: In the experimental groups kefir grains were used with 1, 2, 3 and 4% concentrations (w/w) in flour as sourdough, while in the control group only baker’s yeast was employed. The qualities of the samples were evaluated by the application of Texture Profile Analysis (TPA) after 1, 2 and 3 days and sensory evaluation was conducted after 1 day.Results: The results showed that on the base of sensory evaluation, there were not significant differences (p≤0.01) among the samples regarding appearance, crust, odor, taste, and porosity characteristics. The breads with added 2 and 3% kefir as baker’s yeast indicated better chewiness, texture and softness than the other groups. It was shown that the kefir grains (2, 3, and 4%) delayed the staling as compared to the control group.Conclusion: The concentration of kefir grains is the most important factor in the staling process. Breads produced with added kefir, had lower acidity and longer shelf-life (5-6 day) as compared to the bread made with baker’s yeast.

Introduction: Bread is one of the most popular and important food for man. Some reports have indicated the loss of 300 million dollars per year as the result of bread losses. The object of this research is to investigate the effects of 7 types of nanofilms on the moisture content and bread staling by the application of compact force and shear force.Materials and Methods: The effects of nanofilm on the moisture content and staling by keeping the samples at 5, 20 and 35°C for 21 days were investigated and compared with the blank. SPSS and SAS software were employed to analyze the results.Results: The results indicated that type of films, temperature and keeping period had significant effects on the moisture. Moisture losses in nano packaging were 14-25% less than blank sample. The results also showed that the effect of three factors on bread staling were not significant in respect of compress and shear forces methods. The highest amount of staling was observed in control film without nanoparticle but was reduced in samples with the increase in the nano - particle in nano- films. The results indicated that the temperatures of 20 and 30°C that were experienced kept the freshness better as compared to 5°C and the staling took a longer period, however the keeping quality at 5°C was longer.Conclusion: Nano composite film consisting of 500 ppm silver and 300 ppm clay was superior in reducing staling and preventing the loss of moisture. The results indicated 40 –60% reduction in bread losses.

Introduction: The detection of antibiotic residues in milk is the prime concern in the dairy industry. Several steps have been taken to assure the public that the milk supply is safe. The object of this study was to determine the antibiotic residues in cow's milk.Materials and Methods: 50 samples of raw cow's milk were collected randomly from Ilkhchei region (located in the southwest of Tabriz) at milk collection centers between the months of Farvandin to Khordad 1388. The samples were tested for antibiotic residues by the application of Copan Milk Test (CMT).Results: Out of fifty collected milk samples in the Ilkhchi region five samples (10% of the total samples) indicated positive results concerned with the presence of antibiotic residues.Conclusion: Further studies and tests are required for detection of antibiotic residues in milk collected in Ilkhchi region.