Journal of Food Technology and Nutrition
Year:2012 | Volume:9 | Issue:2 (34)|Papers Count:10

Introduction: Mayonnaise is an oil in water emulsion containing approximately 70-80% oil.Due to the high concentration of oil and its role in formulation, structure and the stability of the mayonnaise, it is the aim of this investigation to evaluate the effect of four different types of edible oils; sunflower seed, soyabean, maize and canola oils on the chemical, rheological and organoleptical charactristics of this product.Materials and Methods: Mayonnaise samples with four types of sunflower, soya bean, maize, rapeseed oils were prepared and stored at 3DC for 7 and 30 days. Oscilatory experiments including the strain sweep measurement in the range of 0.05-700 % and the frequency sweep measurement over the frequency range of 0.001-50 HZ were performed.Proper models were fitted on the emperical results and the model parameters were used to compare the effects of oil types on the mayonnaise samples.Results: Dynamic Oscilatory tests revealed that the type of the oil had significant effects (p≤0.05) on the level of intractions and their magnitude in mayonnaise structure modeled as a network of rheological units. During the storage time the results of sensory and rheological experiments showed that the mayonnaise prepare With sunflower oil had the highest yield stress, acceptiility and stability followed by the mayonnaises samples prepared with soyabean, maize, rapeseed oils respectively.Conclusion: The mayonnaise containing oil with higher unsaturated fatty acids in the formulation showed higher stability and the results of sensory and rheological experiments indicated that the mayonnaise prepared with sunflower oil had the highest acceptiility and stability in comparision with other samples.

Introduction: To assessment of the thermal resistance of oils might be based on some factors and fatty acid profile might be considered as one index. Due to limitations the comparison could not be made on a simple statistical methods. In this paper, Principle Components Analysis (PCA) is used as a method for assessing thermal resistance of sunflower and frying oils. This method is able to evaluate the variance of fatty acids as a common index simultaneously.Materials and Methods: sunflower and frying oils were heated at two different temperatures; 130oC and 190oC and kept at this temperature for 8 hours each day. Oil samples were taken every hour and stored for further chemical analysis until required. The changes in the fatty acid profile as well as peroxide, anisidine and acid values were determined for each sample.The results were assessed by the methods of PCA and Pearson correlation.Results: There is a correlation between the percentage of fatty acid compositions and time for the two mentioned temperatures. There is less correlation for all the samples at the temperature of 190oC. The comparison of samples for each oil with the help of PCA at the two temperatures indicated that variance of samples at 190oC is higher.Conclusion: sunflower oil showed higher variations as compared to the frying oil by the increase of 60oC temperature. There is no difference between the samples of 130oC and 190oC in frying oil as compared to the sunflower oil by PCA. Since the oils being used, were free of antioxidants, the result concerned with frying oil indicated high resistance of fatty acid to heat.

Introduction: Cardiac and blood vessel diseases are major problems in the developed and developing countries. The most important cause of these diseases is atherosclerosis, that high density of plasma lipids is considered the main factor in its appearance and development. The aim of this study was to investigate the effect of kombucha extract on plasma lipoproteins, and liver enzymes in male Wi star rats.Materials and Methods: Animals were divided into 4 groups: l) Control group which received normal water and food diet.2) Sham group which received water and high fat diet (included: 66.5g carbohydrate, 20.lg fat, and 4.49g protein).3) Experimental group 1 received high fat diet and kombucha extract.4) Experimental group 2, received food diet and kombucha extract. The kombucha extract was poured in a container and was put in access of the animals. The duration of the treatment has been continued for 8 weeks. After weighting, the animals were anesthetized with ether. After treatment for 8 weeks, blood serum was prepared and the concentrations of triglyceride, cholesterol, plasma lipoproteins and liver enzymes such as AST and AL T were measured.Results: The results showed that the serum level of cholesterol, LDL, AST and ALT in both experimental groups had no significant decrease as compared with control group, but serum level of HDL had decreased significantly as compared to the control group (p<0.05). On the other hand, serum level of TG in both experimental groups indicated significant decreases as compared to the control group (p<0.001).Conclusion: The use of the kombucha extract can decrease triglyceride and increase HDL serum. Therefore this extract might be used in treating diseases such as cardiac and blood vessel diseases.

Introduction: Traditional buttermilk is a native beverage of iran, especially in villages, where it is consumed to a great extent during spring and summer seasons.Materials and Methods: Buttermilk is an aqueous phase obtained during the churning of yoghurt in Mashk for butter manufacturing. Buttermilk was traditionally made from sheeps milk in East - Azarbayjan (Meyaneh and Hashtrood) rural areas. The physical and chemical compositions of this product were investigated during three lactation periods (beginning, main point and the end). Therefore, 60 Iranian traditional buttermilk samples were collected from the Meyaneh and Hashtrood (30 sample from each zone) in order to determine physical and chemical properties of sour butter milk samples.Results: The results showed that pH, titratable acidity, total solid, ash, salt, crud protein, fat, lactose and density were in ranges of: 3.64 - 3.81, 0.91 - 1 (LA%), 3.51 - 5.47 %, 0.29 - 0.79 %, 0.16 - 0.27 %, 1.99 - 2.75 %, 0.16 - 0.45 %, 0.31 - 0.97 %, 1.0191 - 1.0264 g/cm3, respectively. The results indicated that there were significant differences between physical and chemical properties of samples were taken in different lactation periods (P≤0.05) but there were no significant differences in different zones (P≤0.05).Conclusion: It was concluded that the physical and chemical quality of Iranian traditional buttermilk comply with codex standard for yoghurt drink (doogh).

Introduction: The effect of PET packaging and different storage conditions on the fatty acids profile and some quality factors in three different types of commercial oils in Iran consisting of sunflower seed, canola, and mixed oils (sunflower, soya bean, and cotton seed oils) were studied.Materials and Methods: Fatty acid profile and chemical characteristic namely; peroxide, iodine values, free fatty acid content, induction period and color, were determined (with and without PET pieces) after 20 and 60 days storage at 25 and 45oC.Results: The results showed that time, temperature of storage, and presence of PET pieces have significantly affected the quality factors, therefore storage at 45oC for 60 days with the presence of PET pieces increased the peroxide value by 3.11%, the free fatty acid content by 1.35% with decreased the induction period of these three types of oils by about 1.38%. This might cause the oils unacceptable, according the standards.Conclusion: Our findings showed that the storage of oils packed in pet containers at low temperature (T<30oC) is recommended in order to extend its shelf life.

Introduction: Bread is one of the most important sources of energy and protein for the people in the world particularly Iran. In the production of bread, rheological features of dough are quite important. Some chemical compounds are the dough improver and might act as surface active agents. These compounds are used in the production of dough to produce a better product. Generally, the effect of these compounds on the rheological features of dough has not been investigated thoroughly. The use of additives to foods in general and the fact that the consumers prefer the natural additives, biosurfactants a group of surfactants with microbial origin are considered in this study. Therefore the aim of this research is to investigate the effect of biosurfactant on the rheological features of dough.Materials and Methods: Emulsan was produced from Acinetobacter calcoaceticus and extracted by the use of amunium sulphate method and then 0.05, 0.2, 0.5, 0.75 and 1% were added to the wheat flour and compared to the control dough. The rheological features were measured by the application of Farinograph and Extensograph.Results: The biosurfactant was produced from Acinetobacter calcoaceticus at about 1.49gr per liter of culture. Based on the results, the water absorption increases as the biosurfactant is added, and the absorption increases with the increase in the concentration of biosurfactant.Generally, the viscosity increases rapidly in flours with Emulsan and testes indicated that development time increases while using biosurfactant as compared to the control. The results also indicated that emulsan's treatment in comparison with the control sample increases the stability significantly.Conclusion: The dough containing biosurfactant is stronger and indicated a significant stability as compared to the control dough. In this study, a desirable effect on the rheology of Barbari dough was achieved by using 0.5% of biosurfactant.

Introduction: Probiotics are beneficial microorganisms that inhibit the growth of harmful bacteria of gastrointestinal tract. Pickled cucumber is widely used in Iranian fast foods. The objective of this study was to prepare the probioticated pickle by autochthonous lactobacillus plantarum with desirable sensory property.Materials and Methods: Pickled cucumber products were prepared in different pH and salt concentrations and with or without probiotic starter. Vinegar was used as an acidifying agent and the number of probiotic bacteria, sensory properties were assessed after 15 days incubation at room temperature. Sensory properties of the probioticated pickled cucumber products were assessed using the 5-point category scale.Results: The bacteria isolated from pickled cucumber was confirmed aslactobacillus plantarum by conventional biochemical tests. Bacterial growth favored salinity of 1-5% while in salt concentration of 10% bacterial viability was decreased. The cells stopped growing at pH=3 while at pH values of 5 and 7 cell densities reached 108 cfu/m. The flavor of both probioticated and conventional Iranian pickled cucumber were acceptable.Conclusion: pickled cucumber could be prepared using autochthonous lactobacilli with high viability of probiotic bacteria and acceptable sensory properties.

Introduction: The object of this study was to fortify pasteurized milk with calcium salts in order to prepare a product with higher calcium, lower rennet coagulation time and higher calcium to phosphate ratio.Materials and Methods: Milk was fortified at the concentration of 36mg/100ml using four calcium salts. calcium lactate, calcium gluconate, calcium lactate gluconate and tricalcium citrate. The pH values of the samples were slightly decreased, upon the addition of calcium salts. However, restoration of pH of fortified milk was accomplished by the addition of disodium hydrogen phosphate. Furthermore, tripotassium citrate and kappa Carrageenan were simultaneously used to prevent precipitation of calcium.Results: The results revealed that, calcium lactate gluconate had the highest calcium content, lowest RCT value and the same organoleptic properties like regular pasteurized milk.Additionally, calcium lactate and calcium gluconate in term of above characteristics were placed next to calcium lactate gluconate in the respective order.Conclusion: Fortification of milk with calcium salts would cause an increase in casein micelle size that results in higher calcium to phosphate ratio which is considered ideal for retention of calcium in the body.

Introduction: Studies concerned with the plant metabolites such as tannins, polyphenols and alkaloids have shown that due to their structure are able to act as antioxidants and be employed in various applications even for curing diseases in the future. The aim of this study was the evaluation of the antioxidant activities of phenolic compounds present in the methanolic extracts of two cultivars of sweet potato In Iran.Materials and Methods: Total phenolic compound were determined by the Folin-Ciocalteu method. The antioxidant activities of phenolic compounds present in the samples were determined by the inhibition of linoleic acid oxidation in thiocyanate system and DPPH assay based on the concentration of the scavenging action of free radicals production.Results: Total phenolic contents of two sweet potato cultivars (red and white) were estimated at 108 and 174 mg/100g as Gallic acid equivalent (GAE) based on dry weight, respectively.The extracts of red and white sweet potato cultivars had 95 and 96% inhibitory action in inhibition of linoleic acid oxidation, and EC50 value 11.64 and 12.97 mg GA/ml, in free radical scavenging system. Alpha tocopherol had 85% inhibitory action and the EC50 value=12.61 mg GA/ml for free radical scavenging Conclusion: According to the results of this research, the white cultivar had higher phenolic content than red cultivar. There was significant differents between the antioxidant activities of sweet potato extracts and alpha tocopherol (p<0.05), also, sweet potato extracts had similar radical scavenging activity to alpha tocopherol. Significant (p<0.01) negative correlation was observed between total phenolic content and the EC50 for DPPH radical scavenging, nor between phenolic content and total antioxidant activity.

Introduction: In this century one of the main challenges of the countries especially developing countries is the access to adequate and safe food. The right of man to food and the role of the united nation to execute this process is an essential and vital procedure, therefore it is necessary to investigate this subject thoroughly.Materials and Methods: The methodology of this research is the current political and social sciences based on this study and analysis of the historical documents.Results: According to the international and united nation documents concerning different resolutions, suggestions and recommendations have been issued about the Right to Food and dispute over nutrition. In spite of all the recommendations, and practices malnutrition has been increased.Conclusion: The united nation has been successful for creating the rules, regulations and commitments concerned with the Right to Food and nutrition but has not been successful to implement them.