Journal of Food Technology and Nutrition
Year:2011 | Volume:8 | Issue:1 (29)|Papers Count:13

Introduction: Theoretical calculations of diffusivity into the solids are subjected to a lot of limitations. Consequently in most researches related to the molecular diffusion into the solids and foods, the effective diffusivities are measured by laboratory methods. In this research the effective diffusivity of salt into the potato tissues was measured experimentally applying analytical solution of Fick's equations in mass transfer.Materials and Methods: The cylindrical samples of potato with 3 cm diameter and 3.5 cm height were immersed into the brine. The surrounding surfaces of the samples were covered by a suitable sealant in order to consider one dimensional mass transfer. Variations in brine concentration and consequently the rate of salt diffusion into the potatoes were calculated by measuring the electrical conductivity of brine.Results: The diffusivity of salt into the potato tissues is increased by increase in brine concentrations, but it won’t be remarkable increase at high brine concentrations. The salt concentration in potato tissues reaches to equilibrium in 300 min and then no more diffusion will be occurred. Using the results of experiments and analytical solution of Fick’s law equations the diffusivity of salt into the potato tissues at 24°C were measured to be (3.45- 4.39) 10-9×m2/s for 1-3% (w/v) brine solutions.Conclusion: According to the results of this research, Fick’s law equations in mass transfer and their analytical solutions represented by Crank give a precise explanation of mass transfer in solids. Furthermore, the diffusivity of salt in the potato is independent of the variety of potato and consequently different researches have concluded similar results.

Introduction: Milk is one of the most important nutritional source and is defined as a complete food. The average mineral content of milk is 7.3 g/L. Low sodium milk is considered as a dietary item in treatment of a number of diseases, therefore in the present investigation, it was decided to prepare milk with low sodium content.Materials and Methods: In this study low sodium milk was prepared using cation exchange chromatography and later low sodium yoghurt was produced. Milk and yoghurt samples were analyzed for ash, minerals, (sodium, potassium and calcium) fat, protein contents, pH and sensory attributes.Results: The results indicated that sodium content decreased from 486.25 mg/L to 70.25 mg/ L while potassium and calcium contents increased and fat, protein, ash contents and pH did not change significantly. Results of sensory evaluations showed no significant differences. Low sodium yoghurt showed that the ash content and sensory evaluations were not significantly different from the ordinary yoghurt, however sodium content decreased from 535 mg/L to 74.33 mg/L, and potassium and calcium contents increased.Conclusion: This study showed the production of low sodium milk and yoghurt. Potassium and calcium contents increased and it was indicated that low sodium content did not change sensory attributes in these products.

Introduction: Licorice as a native and traditional plant of Iran contains Glycyrrhizic acid (GA) or Glycyrrhizin, a substance claimed to be up to 30-50 times sweeter than sucrose.Three different techniques of glycyrrhizic acid extraction from licorice extract powder have been compared.Materials and Methods: Modified Roussin technique (Method 1), Dissolving the licorice extract powder in distilled water and treatment with ethanol and sulphuric acid (method 2).Application of microwave (Method 3). High performance liquid chromatography was used to separate and determine GA and find the yield of extraction by various techniques.Results: The results showed that the yield by the third method of extraction was higher (28.84%) than the second (8.5%) and the first method (4.6%), which might be due to the effect of higher temperature and pressure applied in microwave technique.Conclusion: Microwave extraction method proved to be a quicker method and provided higher extraction yield as compared to other conventional methods.

Introduction: Salmonella typhimurium is an international food-borne pathogen, which regularly causes 3 million cases of death worldwide each year. Due to the fact that a sugar like sucrose has many applications in the food industries; therefore the aim of this study is to find out the effect of water activity when sucrose is utilized, on the Salmonella typhimurium viability at high temperatures. Materials and Methods: Tripticase Soy Broth (TSB) supplemented with different concentrations of sucrose was prepared. These media that have different water activity were inoculated with S. typhimurium and they were heat treated with a range of 50 to 80°C degree temperature. Viable counts of the organisms after heat treatment were performed using Blood agar plates.Results: The result showed that, at temperatures more than 70°C, Salmonella cells at low aw were more heat tolerant than those at a higher aw but below 65°C the reverse was true. The bacteria present in different aw value indicated dramatic changes in morphological characteristics.Conclusion: The bacteria namely Salmonella typhimurium in low aw environments might tolerate higher thermal processes.

Introduction: Belonging to the family of Lamiaceae, peppermint (Mentha Piperita L.) is a therapeutic and aromatic herb whose extract has various applications in food, cosmetic, hygienic and pharmaceutical industries.Materials and Methods: The level of minimum inhibitory concentration (MIC) of Menthapiperita L. essential oil and a chemical preservative used in food industries (Sodium Benzoate) were determined against three microorganisms E. coli (PTCC 1330), Bacillus subtilis (PTCC 1254) and Salmonella typhinurium (PTCC 1622).Results: The results showed that MIC of Mentha piperita L. essential oil for the above microorganisms is 1000 ppm, while MIC of Sodium Benzoate on Salmonella typhimurium (PTCC 1622) is 3000 ppm and on the other two, E. coli (PTCC 1330) and Bacillus subtilis (PTCC 1254)) is 3500 ppm.Conclusion: Considering the results it was concluded that the essential oil of peppermint has stronger antimicrobial activity as compared to Sodium Benzoate.

Introduction: The importance of oils and fats apart from the health point of view is their role in commerce and economy. Therefore a search and survey concerned with quantitative and qualitative losses and wastes is essential to be carried out which is the object of this work.Materials and Methods: 2 oil-extraction plans in Tehran province were chosen as samples. Questionnaires were provided concerned with operations, processing’s and estimated amount of losses and wastes in different phases of operations. MINITAB software was applied for variance analysis computation in order to compare and estimate the amount of losses and wasted in different phases of oil seed extraction operation.Results: The study and search indicated average losses of 5-6%, 4-5% and 3-4% for sunflower, and canola and soybean oils respectively during extraction operation.Conclusion: The financial losses might be regarded considerable and significant in respect of the amount of seed processed annually and the amount of oil extracted and received and the quantity lost.

Introduction: Appropriate complementary feeding, due to its importance in child growth and development, is a health priority for child nutrition in developing countries. This study was concerned to evaluate the common local foods in child feeding with its nutritional value and adequacy in northern rural areas of Tehran.Materials and Methods: This cross-sectional descriptive study was preformed on 40 mothers having children aged 6 to 24 months and living in areas named AFJEH, KONDEOLIA, BOOMEHEN and BAGHEKOMESH located near Tehran by using observation and interview methods through questionnaires and visiting in 1383. Questions were based on the name, appearance, ingredients and preparation of each traditional food. Data were assessed by application of Nutrition III software.Results: Varieties of complementary traditional foods specific for children consisting of stews, rice, soups, vegetable quiche and borany are offered on Iranian tables which are different in appearance, taste, aroma and color which are based on cereals, vegetables and roots and only in some products namely stews and quiche, animal produce might be included. The starch and carbohydrate content of these foods are high but vitamin and mineral requirements of child are not provided due to the low bioavailability. Conclusion: It is concluded that the traditional child foods are not able to provide the nutritional requirements particularly the micronutrients. Therefore in order to implement the traditional complementary feeding policy due to it's low cost, accessible and acceptance, it is required to increase their nutritive values by fortification and also to educate mothers to improve food preparation methods by nutritionists, nurses and midwifes in health centers.

Introduction: In this study, the contents of selenium were determined in liver, kidney and muscle tissues of eighteen from the Sciaenidae family (Otolithes ruber), which were caught, from the Persian Gulf in Abadan, Bushehr and Mahshahr cities.Materials and Methods: The determination was performed by Hydride Generation Atomic Absorption Spectrometry (HGAAS). The limit of detection for selenium was 0.7mg/kg and the repeatability of measurements, as the means of RSD was 0.94% and the RSD of the whole procedure were 2.86%. Separation and identification of selenium compounds were accomplished by headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS).Results: Selenium compounds speciation in fish tissues by SPME-GCMS demonstrated that organo-selenium in the samples were dimethylselenide, diethylselenide and dimethyldiselenide.Conclusion: The content of selenium Otolithes ruber samples (35 mg/day) was in the safe dose (50-200 mg/day); consequently, selenium compounds in fish Sciaenidae family were not toxic.

Introduction: A major part of Iranian food production concern confectionary products. Due to the high consumption and the fact that these products are susceptible to microbial contamination, this study was conducted to understand the level and degree of contamination in cream Filled pastries. Materials and Methods: In this cross sectional study, one hundred sixty samples of pastries from 80 different confectionaries in Tabriz were collected and microbial tests were conducted according to Iranian National Standards. The collected data were analyzed by Ttest and Frequency test.Results: The results of this study revealed that the level of contaminations for coliforms (38.8%), E- coli (48.8%), S. aureus (31.2%), moulds (27.5%) and yeasts (70%) were higher than the standard defined by the Iranian National Standard. There were not significant differences between the samples taken from different confectionaries.Conclusion: According to the findings, the rate of microbial contamination in cream filled pastries is high, therefore application of methods which might concern the use of standard raw materials together with the personal hygiene and education of the workers is required in order to improve the safety of products. 

Introduction: Soybean due to its oil content and protein concentrate is regarded as a valuable agricultural product. The oil and the concentrate is employed by different food industries and applied in many food formulations. Therefore the aim of this work is to evaluate the oil extracted from eight different varieties of improved Soybeans (M4, DELSOY4210, L11, DPX, 032, M9, J.K, TNS56).Materials and Methods: The extracted oils were subjected to a series of chemical as well as some plysical tests according to AOCS and AOAC method of analysis. The tests involved the determinations of oil, nonsaponifiable matter, phospholipids contents, induction period measurements, acid value, peroxide value, iodine value, fatty acid composition and qualitative and quantitative measurements of fractions present in the nonsaponifiable matter. Experimental means were compared using Duncan's multiple range tests with 4 replications. DELSOY4210 variety was compared with others and might be considered a superior variety. Results: In this research work, Delsoy variety due to its oil content (25.3%),higher concentration of oleic acid, lowest amount of a- linolenic acid, high content of a- tocopherol, and relative resistance to oxidation as compared to other varieties might be considered a desirable variety. The DPX, M4 and 032 varieties had the highest amount of phospholipids, resistance to oxidation and linoleic acid in respective order. Therefore all the varieties are considered valuable.Conclusion: Considering the fatty acid composition, fractions present in the nonsaponifiable matter particularly tocopherols and other properties such as the presence of different concentrations of phospholipids in different varieties, suggests that particular variety might be employed for specific application.