Journal of Food Technology and Nutrition
Year:2017 | Volume:14 | Issue:1 (53)|Papers Count:15

Introduction: Heavy metals are environmental pollutants and can cause chronic and acute toxicity in human body through exposure to polluted water and food. The aim of the present study is to measure the amount of four heavy metals (Lead, Chromium, Copper, Iron) in50 samples of Iranian traditional dough and bread to determine the influence of ovens, pH, dough surface, temperature and baking time.Materials and Methods: Samples of dough and bread were randomly collected in Tehran.The amounts of metals were measured using Atomic Absorption Spectrometry. The results were analysed and compared with national and international standards using statistical software (SPSS).Results: The results indicated that the amount of Chromium in all the tested samples were less than the limit of detection. Increased amounts of Lead in the samples after baking were not statistically significant (P>0.05). Increased amounts of Iron in rotary and traditional oven and increased amounts of Copper in Lavash and Taftoon breads in traditional ovens were statistically significant (P< 0.05).Conclusion: The analytical results showed that the average amounts of Lead and Iron (due to flour fortification in Iran) were more than the values specified by the WHO/FAO. This organization defines a Provisional Tolerable Daily Intake (PTDI) of4 metals per person per day by consuming bread, however the amounts of measured heavy metals were less than the standard values specified by WHO/FAO. Therefor the cumulative effect of heavy metals is important and should be considered in body tissues.

Introduction: Mentha aquatica is one of the species of mint family. The essential oil of this plant has shown effective antimicrobial properties on various kinds of microorganisms in the culture. This study aims to investigate the preventive influence of Mentha aquatic essential oil on viability of Kluyveromyces marxianus in Iranian yoghurt drink.Materials and Methods: Mentha aquatic essential oil was obtained by distillation method employing Clevenger apparatus. The effective composition of the essential oil was identified by Gas Chromatography equipped with Mass Spectrometer (GC/MS). The inhibitory effect of Mentha aquaticessential oil on kluyveromyces marxianus was examined on Muller Hinton agar culture using diffusion disk method. After assurance of its antimicrobial properties, the Inhibitory influence ofMentha aquatic essential oil was studied on Kluyveromyces marxianus at0.05, 0.1, 0.125 and 0.25% concentrations in Iranian drinking yoghurt during 28 days of storage.Results: The results showed that Mentha aquatica essential oil has the highest inhibitory effect on Kluyveromyces marxianus growth at high concentrations. Concerning the antimicrobial property and organoleptic characteristics, it might be concluded that0.1% concentration of the essential oil might be regarded as the optimum concentration.Conclusion: It can be concluded that Mentha aquatic essential oil, caused a declining effect on the viability of microorganism studied.

Introduction: Oxidative rancidity is one of the important reactions in oils and fats. Tea contains some effective antioxidants namely tannin and catechins. In this research project the antioxidative activities of tea extract in comparison with tannic acid has been investigated.Materials and Methods: This study was carried out in order to compare the effects of three different extraction methods consisted of methanolic extraction, agarwal method and extraction with hot water. In order to investigate the antioxidant activities, three concentrations of tannic acid (0.01%, 0.05% and 0.1%) and tea extract (0.1%, 0.5% and 1%) were added to four types of oils with different fatty acid unsaturation and composition (sunflower, canola, olive oils and tallow) separately. The induction period was measured by Rancimat at120ºC and peroxide values were determined after 24 hours of heating intervals at 105ºC for six consecutive days.Results: According to the results, the highest extraction yield belonged to the hot water extraction method. The results showed that different concentrations of tea extract had antioxidative property.In sunflower and canola oils, 0.5% tea extract and 0.1% tannic acid and in tallow and olive oils, 1% tea extract and 0.1% tannic acid showed the highest activity to increase the induction period and to prevent the increase of peroxide values of oils. Olive oil containing natural antioxidants and tallow that is deficient in natural antioxidants showed increased induction periods as the concentrations of the extract were increased.Conclusion: Tannic acid and tea extract exhibited antioxidant activities by increasing the induction periods of oils and fats while preventing the increase of peroxide values.

Introduction: The consumption of synbiotic products (simultaneous presence of probiotic and prebiotic) has beneficial effects on human. The aim of this study was to evaluate the effect of inulin and lactutose on the characteristics of probiotic ultrfiltrated feta cheese.Materials and Methods: In this study, prebiotic compounds consisting of inulin and lactulose (solely or in combination together) andLactobacillus casei were used to produce probiotic ultra-filtrated Feta cheese. The survival ofLactobacillus casei and physicochemical and sensory properties of probiotic ultra-filtrated (UF) cheese concerned with different storage days (1, 15, 30, 45 and 60 days) were evaluated.Results: pH values for all the cheese samples were decreased significantly (P<0.05) during storage. In other word, the amounts of acidity for all of the samples increased significantly during storage (P<0.05). Moisture variation and contents were in a decreasing trend until the end of the storage period (P<0.05). Sample containing inulin (I), sample containing lactulose (L) and sample containing inulin and lactutose (IL) had the best sensory quality in comparison to the control sample (C). At the end of the storage, the number of Lactobacillus casei was higher in samples I, L and IL as compared to the control.Conclusion: In this research work, the final synbiotic cheese containing more than 107 CFU/g viable Lactobacillus casei at the end of storage might be regarded as a probiotic product. The prebiotic compound has improved sensory and physicochemical properties as well as viability of Lactobacillus casei in probiotic ultra-filtrated Feta cheese as compared to the control.

Introduction: The essential oil of lemon balm (Melissa officinalis) and pennyroyal extract (Mentha pulegium) are widely used for food flavoring and beverages due to the pleasant spicy flavour. The antibacterial activities of these plants have been proven in several studies. The aim of this study was to investigate the growth inhibition of food spoilage yeasts by lemon balm essential oil and extract of pennyroyal.Materials and Methods: The chemical compounds of the essential oils were analysed and identified by GC apparatus connected to the mass spectrometer detector. The total phenolic compounds of the extract of pennyroyal were determined by Folin-Ciocalteu method. The anti-yeast activities of (minimum inhibitory concentration and mortality) lemon balm essential oil and extract of pennyroyal against yeasts causing food spoilage were assessed by using microdilution.Results: The results showed that geranyl acetate (25.29%), sytral (12.38%), z-sytral (14.3%), e- sytral (9.45%) and geraniol (9.55%) were the main constituents of the essential oil of lemon balm. The total amount of phenolic compounds in pennyroyal extract based on gallic acid was252.48±0.2 mg/gr. Minimum inhibitory concentrations of lemon balm essential oil againstSaccharomyces cerevisiae, Rhodotorula glutinis and Kluyveromyces marxianus were 1.562, 3.125 and 0.195 mL/mL, respectively and the minimum inhibitory concentrations of pennyroyal extract, for the above mentioned microorganisms were17.500, 14.583 and 14.583 mg/mL, respectively.Conclusion: The lemon balm essential oil and the extract of pennyroyal have shown antimicrobial activities and might be employed as natural products in food industry successfully.

Introduction: Starch might be regarded as a polysaccharide consumed considerably. Starches as a food ingredient has important roles in the texture of food. Starch is used in food industry as thickening, stabilizing and gelling agent but some limitations such as low shear stress resistance, thermal decomposition, high tendency towards retrogradation and high syneresis might limit its application. The modification of starch can alter its physical and chemical properties and improves its functional characteristics Materials and Methods: In this work, starch isolated from barley grains, the variety Bahman was cultivated in Lordegan area of Chaharmahal and Bakhtiyari province and acetylated with acetic anhydride (%6 w/w) at two different times of 10 minutes and 5 hours followed by the evaluation of physicochemical properties concerned with syneresis, swelling power, thermal properties, viscosity and morphological characteristics.Results: The results showed that acetylated starches had higher swelling power. There was not a significant difference between the starch acetylated at10 min and the control but this difference was considerable with the acetylated starch at5 hours and the control (p˂5%).Decreases in syneresis and gelatinization temperature and increase in viscosity were significant as compared to the native barley starch. These modifications altered the size of the starch granules.Conclusion: According to the results, modification of barley starch can improve some of its functional characteristics.

Introduction: Color development during frying process is a surface phenomenon that depends on the processing temperature and time and might concern other aspects. The aim of this research was explanation of color changes and behavior of French fries during the process as a mathematical model at various temperatures.Materials and Methods: Blanched potato stripes were fried using a fryer equipped with thermo controller where the sunflower oil was used as a frying media at the temperature of 145, 160 and 175 ºC for 60, 120, 180 and 240 seconds. Surface temperature of the product was measured using T type thermocouple that was located about1mm below the surface of the strip and recorded using data logger by2 seconds intervals during process. Color parameters as brightness (L), redness (a) and yellowness (b) were achieved using Lovibond apparatus and kinetic model was fitted on their changes versus time using MATLAB software version of2009. Finally, critical temperature of color changes during frying was specified by carrying out statistical analysis of equivalent values of color change intensity (DE¥) as completely randomized design and Duncan mean comparison with95% confidence level using SPSS software version of19.Results: The results of this experiment showed that the main part of color parameter changes occurred during early stages of frying process. Higher temperature caused less brightness (L), more redness (a) and more yellowness (b) (more acceptable). The temperature of 160oC can be defined as the critical temperature for significant changes (P£0.05) in the color intensity.Conclusion: Kinetic of crust color changes in French fries follows the raising exponential equation of R2=0.99. Applying high temperature and short time process can be suitable for the control of color quality and therefore food safety.

Introduction: Due to the recognized antioxidant activities of compounds present in herbs and spices, there has been considerable interests concerned with this subject and the biological systems. This research work has been carried out in order to investigate the antioxidant activity ofDorema Aucheri plant and also the application of its ethanolic extract to refined bleached and deodorized soyabean oil to retard the rate of oxidation.Materials and Methods: The effects of water and 96% ethanol as solvents on extracting efficiencies of phenolic compounds and flavonoids of the sample were investigated. The antioxidant activities of the samples with different added concentrations of the extract using DPPH radical scavenging and Ferric-reducing power were determined and evaluated.Results: The results showed that the aqueous extract has the highest extraction rate as compared to the ethanolic extract, however the highest concentrations of phenolic compounds (21.73 ± 0.89 mg GAE/g) and flavonoid (14.99 ± 0.60 mg QE/g sample), and the lowest IC50 concerned with DPPH (2.05 mg extract/ mg DPPH) and the highest rate of Ferric reducing power (14.13 ± 0.06 mM Fe+2/mg) were related to the ethanolic extract. The results of oven test also indicated that the ethanolic extract at certain concentrations could control the rate of oxidation.Conclusion: The results of this investigation suggested that the Dorema Aucheri ethanolic extract might be employed as an antioxidant. Therefor one might introduce Dorema aucheri as a good source of natural antioxidant due to the presence of phenolic compounds.

Introduction: The genus Arcobacter is classified together with the genus Campylobacter into the family Campylo bacteriaceae. Arcobacters are gram negative, non-spore forming, microaerophilic microorganisms that are discriminated fromCampylobacter genus by growth in the presence of the oxygen and low temperatures. They are curved rods, S-shaped or helical cells.A. butzleri is considered the most common species of the genus being considered as a zoonotic and emerging foodborne pathogen. The main objective of this study is to determine the detection and the frequency ofA. butzelri from the poultry products retailers in Tonekabon and evaluate the using culture and PCR techniques.Materials and Methods: Standard culture technique was used for isolation and for the purpose of determination and identification, standard phenotyping tests were applied. The results of phenotyping were carried out by the application of PCR and specific reproduction of Arcobacter.Results: Totally, 95 samples of the poultry meat were collected and tested to study the presence of the species of Acobacter butzelri. On the basis of the culture tests, 12 samples out of the studied95 samples (12.63%) were infected with Arcobacter butzelri. PCR technique also confirmed the results of phenotyping.Conclusion: Although this bacterium has been almost isolated from all enviromental reservoirs, poultry can be considered as the main reservoirs of theArcobacters. For this reason, the presence of this pathogenic bacterium in the poultry meat increase the possibility of its transfer to human through consumption of the products.

Extraction of gums from plant seeds have recently become very attractive.Wild sage seed is cultivated in large quantities in different regions of Iran. This seed gum has good functional properties which is comparable with commercial food hydrocolloids.Materials and Methods: In this study the effect of gum extraction temperature at three levels and pH of aqueous solution at three different values and the ratio of water to seed at two levels, on mass transfer kinetics of wild seed gum extraction were investigated.Results: The results indicated that the increase in the temperature from 25 to 55°C resulted in higher gum extraction (pH of7 and water to seed ratio of 30 to 1). The maximum value of gum was extracted at neutral condition and by increasing the ratio of water to seed (40 to 1), the rate of extraction of gum was also increased. The physical modeling of gum extraction process was carried out and was compared with the experimental data.Conclusion: The experimental data were fitted to a mathematical model of mass transport and equation constants were obtained. Statistical results indicated that the model used in this study was able to predict the gum extraction from wild sage seed adequately and will be a useful tool for other gum-containing seeds.