IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2016 | Volume:13 | Issue:57|Papers Count:21

Sour orange is a citrus with high antioxidant content (mainly ascorbic acid and phenolic compound). Its juice is consumed as a food seasoning. Thermal pasteurization is a common way to improve safety of sour orange juice. By considering the high thermal sensitivity of ascorbic acid and phenolic compounds, the aim of this study is the investigation of the effect of thermal processing on ascorbic acid, total phenol and an antioxidant capacity of sour orange juice at 70, 75, 80, 85 and 90oC in 76, 66, 48, 35 and 21 min, respectively. Ascorbic acid and total phenolic content were measured according iodine titration and Folin- Ciocalteu methods, respectively. Ascorbic acid and total phenol degradation during thermal processing were evaluated by Arrhenius and Eyring models. Enthalpy of ascorbic acid degradation changed slightly due to its high thermal resistance (29.15oC) and free energy (101.11-102.64 kJ. mole-1). With 5oC increase in temperature, the half-life of ascorbic acid and the total phenol content decreased about 1.31 to 1.80 and 1.39 to 2.05 times, respectively. Also there was a good correlation between total phenol content and DPPH of sour orange juice (R2>0.97).

In this research the effect of different drying conditions of microwave fluidized bed (inlet air temperature, inlet air velocity and microwave power) on drying time, effective moisture diffusivity, shrinkage and total energy consumption of pistachio kernel was studied. Data analysis and optimization of drying process of pistachio were conducted by response surface method and central composite design. Input (independent) parameters were: inlet air temperature, inlet air velocity and microwave power. Dependent (output or response) variables were: drying time, effective moisture diffusivity, shrinkage and total energy consumption. The primary moisture content of pistachio kernels has been determined 0.569 (d.b.). Drying of the kernels was performed at three levels of air velocity (1.16, 3.32 and 8.48 m/s), three levels of input air temperature (40, 55 and 70oC) and three levels of microwave power (220, 330 and 440W). The obtained effective drying time, moisture diffusivity, shrinkage and total energy consumption of pistachio ranged between 1.2 to 3.83 h, 2.7×10-10 to 1.32×10-09 m2/s, 12.01% to 35.43% and 0.337 to 1.63 kWh, respectively. The optimum point occurred at air temperature of 38.48°C, air velocity of 1.16 m/s and microwave power of 440 W. Response variable values for drying of Akbari cultivar of pistachio with fluidized bed microwave dryer at this point were drying time of 2.677 h, effective moisture diffusivity of 5.179×10-10, shrinkage percent of 18.41% and total energy consumption of 0.7109 kWh.

Aim of this study was to produce prebiotic clear apple juice that in addition to having healthy effects for consumers could keep its quality properties. In this investigation Inulin, fructooligosaccharide and polydextrose, were added to clear apple juice as prebiotic components in three dosages: 1.5, 2.5 and 3.5 percent and one sample was prepared as a blank without adding any prebiotic. All samples were held in 4°C and 25°C for 6 month and some of their physicochemical characteristics including soluble solids (Brix), reduced sugar and total sugar were measured in the first day of production and at intervals of one month for the whole 6 months. The results showed that with adding prebiotic the amount of Brix, reduced sugar and total sugar was increased. For Brix it became of 14.1% in control sample to 17.6% in samples that contain prebiotic, reduced sugar was 9.45 g/100 ml in blank and after adding prebiotic it became up to 10, total sugar was near 12 in blank and after adding prebiotic it became 13 and 14 up to kind of prebiotic. The most amounts for reduced sugar was in samples containing poly dextrose and the least amount was in samples containing inulin. For total sugar the most amounts was in samples containing inulin and the least amount was in samples containing polydextrose. Increasing in dosage of prebiotic increases the variation amount in comparison to blank sample and samples contain less prebiotic. With increasing of the temperature and time of storage the rate of reduced sugar changing increased and total sugar changing decreased for each sample in comparison to the control sample and it doesn' t any effect on Brix. Samples with prebiotic were sweeter than blank in result of their sugar content and inulin and fructooligosaccharide create sweetener product.

In this study, physicochemical indexes such as acidity, peroxide value, saponification value, iodine value and refractive index by standard methods and fatty acids profile by gas chromatography in 8 samples of animal's butter (cow and sheep) in Quchan and Dargaz cities in spring and summer were studied. The Highest contents of acidity, peroxide, saponification value, iodine value and refractive index were observed to be (0.54 % oleic acid), (0.73 mEq peroxide), (236.53 mg KOH per g), 35.03 (g iodine) and (1/455 °) in the Quchan summer cows' butter, Dargaz spring cows' butter, Quchan spring cows’ butter, Dargaz spring cows' butter and Quchan spring sheep's butter respectively. In the other hand, the lowest contents of this indexes were observed to be (0.11% oleic acid), (0.22 mEq peroxide), (288.88 mg KOH per g), (27.16 g iodine) and (1.453) in the Dargaz spring cows’ butter, Quchan spring cows' butter, Dargaz summer sheep's butter, Quchan summer sheep's butter, Dargaz spring cows' butter respectively. The contents of saturated fatty acids (%), monounsaturated (%) and polyunsaturated fatty acids (%) were found to be59.9, 36.06 and 3/67 % in spring cows' butter and 53.25, 43.31 and 4/33 spring sheep's butter respectively. The contents of this fatty acids were found to be 55/41, 34.04 and 3/84 in summer cows' butter and 52.16, 37.28 and 4.18 summer sheep's butter respectively.

Walnut (Juglans regia. L) belongs to juglandaceae, is a native fruit of Iran. Walnut is a rich source of unsaturated fatty acids like omega-3 and contains high levels of vitamin E, polyphenols, flavonoids, arginine and fiber. On the other hand, walnut causes many positive effects on human health that makes it worth. In this study, we used downgrade walnut to processing it to the walnut drink as a new drink that is nutritious and healthy. For production of walnut drink carrageenan gum addition was investigated. In this regard, carrageenan gum was added in three levels 0.3, 0.6 and 0.9% and the effect of carrageenan gum addition on walnut beverage was investigated. The effects of gum on pH, Brix, Acidity and total sugars were analyzed and overall acceptability was evaluated by Hedonic scale. Walnut drink color was estimated and analyzed by Image J software. Based on the results, the carrageenan gum addition at level 0.6%, were effective on physicochemical characteristics and quality improving at P<0.05. Sensory analysis showed that, carrageenan gum addition had a significant effect on walnut drink stabilization. Statistical analysis showed that the increasing of gum causes L* index to be declined. The effect of gum on b* and a* indicated that treatments contained less gum inclined more towards yellow and less green respectively.

Despite numerous kinds of cheeses they can be categorized into two main groups namely Traditional and Industrial. In Semnan province, north central of Iran, varieties of traditional dairy foods are produced among which Aroushe cheese is the most popular. In this study, Aroushe cheese is produced based on the traditional procedure and predefined condition and then its chemical, reological and sensory properties are characterized. This product is a processed cheese that is produced through simultaneous mixing and heating of the crude for a relatively long time (3-4 h). According to the presented results, the fat, protein and moisture of Aroushe cheese are 35%, 42% and 5%, respectively. Therefore, the shelf-life may be expected to be too much longer than other conventional cheese even in room condition. Based on the reology data of this study, G' is greater than G" at any given point, that means the elastic component dominates over the viscoelasticity which indicates a viscoelastic solid behavior. Finally, the micro-structure and color of Aroushe cheese are determined by SEM and Hanterlab.

This research carried out in order to corn kernels drying by using a discontinuous rotary drum dryer. This research evaluated the effect of drying air temperature and velocity of the rotating cylinder parameters on the drying time, breakage percentage, cracking, burn kernels and the disruptive energy of corn kernels. For this purpose, a batch dryer rotating cylindrical drum rotation is designed and developed. Intake air temperature parameter Was considered at four levels of 40, 60, 80 and 100 oC and the drum rotation speed at three levels of 2, 6 and 10 rpm. The results indicated significant interaction effect of temperature and speed rotation cylinder on maize grain drying. The lowest time kernels corn drying and the cylinder rotation speed was at 100 oC and 2 rpm, respectively. With increasing temperature of dryer from 40 to 100 oC, grain drying time is reduced to less than a quarter but; with increasing rotation speed of the cylinder drying time was increases. During the drying process, the interaction of temperature and rotation speed of the cylinder has no significant effect on broken kernels-corn. The maximum percentage of broken grains of corn is in 10 rpm rotation speed. Interaction of temperature and rotation speed of the cylinder is significant at the one percent level on cracked and burned grains. The More of the cracks and burn is in 100 oC temperature and 2 rpm of rotation speed.

The investigation of microbial flora in dairy factories and the role of environmental factors are very important. This study was to determine the microbial air contamination in various parts of dairy factories in Shahrekord. In this study sampling was done by using sedimentation method. Microbial analysis included counting total aerobic bacteria, staphylococci, bacillus, yeasts, and molds. In each sampling series the plates containing the selective medium, for 1hour, were placed 1meter away from wall and in the height of 1meter from ground in different parts, then the samples were transferred to laboratory and have been kept in 37oC in incubator for 48hours. After counting the colonies, specific biochemical tests were used for determining isolated bacteria identity. For evaluating of fungal the Potato dextrose agar mediums containing choloramphenicol were used. The gender of grown fungal was determined by using routine laboratory methods including the teased mount and slide culture technique.The results show that the total bacteria number in air, Among the total isolated colonies, the contamination ratio to gram positive cocci was 44%, gram positive bacilli was 53.1%, gram negative bacilli was 2.7%, and gram negative cocci was 0.57%, Among the total isolated bacteria the most bacterial type was related to Staphylococcus aureus, Bacillus cereus, and Escherichila coli respectively. Also, the results of counting fungi numbers in air showed that, Among the total 313 various isolated fungal colonies, yeasts 60.3%, Trichosporon14.6%, Paecilomyces 7.6 %, Geotrichum 5.7%, Madurella 5.7%, Cladosporium 2.5%, Aspergillus 2.2%, Monillia 1% and Rhizopus 1% were investigate.According to the suggested air microbial contamination standard amount by America Public Health Association, the results of this study show that the air of different parts of factories have high contamination and the possibility of transfer of contamination to products of these factories is high.

In this study the effect of different amounts of gelatin (1, 2, and 3 g) and sodium caseinate (1, 2, and 3 g) on sensory characteristics, image processing and texture of chocolate mousse was investigated and the relationship between sensory parameters - device was determined using principal components analysis method. Results showed that the gelatin had a great impact on the sensory characteristics. Results of texture analyzer showed that hardness, adhesiveness, gumminess and chewiness was being greatly affected by gelatin and these parameters increased with increasing gelatin but springiness was more dependent on the sodium caseinate. Entropy, fractal dimension, bubble size and porosity decreased with increasing gelatin. The amount of spherical bubbles also showed no significant difference. Results of principal components analysis showed that some textural characteristics (hardness, gumminess and chewiness) had close relationship.

There is currently a very high demand for all forms and preparations of medicinal plants worldwide. Accordingly, hops has been drawing significant attention in recent years. Hops is a medicinal plant with various applications in traditional medicine. In the present research work, antifungal effect of hops flower ethanolic extract on S. cerevisiae and some bread spoilage molds (Aspergillus niger, A. flavus, Penicillium chrysogenum, P. citrinum, Rhizopus oryzae and Rhizomucor spp.) was investigated. The antifungal effect was determined by using broth dilution susceptibility test. Results showed that the ethanolic extract of hops flower had the ability to prevent mold growth on bread samples. Inhibitory concentration of the extract was in the range of 1.875 to 3.3 mg/ml. The extract had no effect on Saccharomyces cerevisiae in the concentrations of 0-15 mg/ml. It was concluded that ethalonic extract of hops flower has remarkable negative effects on food spoilage mold growth, especially bread spoilage molds. To apply this extract as a natural food preservative, further researches are required.

Dill (Anethum graveolens) is a plant belonging to the Apiaceae family rich sources for tocophorol and phenolic content, including antioxidant activity. These diet antioxidants are important as they protect human body against oxidative stress and therefore maintain appropriate health. The propose of this study evaluate the effect of extraction methods (ultrasound and Microwave) and solvents (ethanol, ethanol/water (50: 50), and water) on tocophorol and phenolic content and antioxidant properties of dill extracts are to determine the most suitable extraction method for optimal use of this product. The antioxidant activities of each extract are evaluated with the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), bcarotene bleaching and oxidative stability index (OSI). In all antioxidant assays the ultrasound water/ ethanol and ultrasound-ethanol had highest antioxidant activity and they didn’t have significant difference with synthetic antioxidant TBHQ. According to the result dill extract with the method of ultrasound ethanol/water and ultrasound- ethanol can be replace with synthetic antioxidant in food industries.

Raspberry is a good source in terms of antocianines, polyphenols, vitamin C, fibers, proteins and minerals contents. Raspberry juice is susceptible to enzymatic and microbial reactions, because of its high moisture content (75-90%). Concentration of Raspberry juice increases its shelf life, while decreasing costs of storage and transport. In this study, extracts obtained from two raspberry cultivars of Amol (red) and Siyahkal (black) were concentrated by two methods, radiation (microwave) and convention (evaporator-rotary) applying three pressure levels: 12, 38.5 and 100 kPa. Changes in physicochemical properties including brix, acidity, pH, turbidity and color were assessed during the concentration process of two kinds of juice. Results showed decrease in acidity and color and increase in brix and turbidity of the juices, but rate and amount of changes were dissimilar in different methods and pressures. Samples concentrated by radiation using microwave in comparison with conventional method (evaporator-rotary) had superior quality. Furthermore, decrease in pressure led to better quality in product in both techniques.

In this research different methods of DNA extraction from Aspergillus niger in tomato paste have been optimized and compared with each other. For this purpose classical optimization techniques and commercial Kit base methods were used. Mold spores of Aspergillus niger at different levels (101, 103 and 105 CFU/g) were added to the tomato paste. After mycelium growth DNA extraction was perfomed by five methods. Different methods employed by use the Liquid nitrogen, ultrasonic and lysis solution in the cell wall. These methods in terms of quality and quantity of DNA extracted were studied using spectrophotometer with NanoDrop. The absence of smear, protein contamination and no presecnce of PCR inhibitors determined with PCR that performed forward and reverse primers. Result of gel electrophoresis and PCR assay showed that Method 1 is the most appropriate method for DNA extraction is the mold of tomato paste.

Sensory indices, microbal communities, qualitative parameters and fatty acids profile of smoked Kutum and Golden Mullet were evaluated at the Northern Iranian markets. Thus, the samples from selected markets were collected and analyzed and compared also with acceptable ranges. The results showed that there were differents in some indices between smoked Kutum and Golden Mullet such as color and texture as sensory, pH (6.30 and 7.74% respectively), total lipid (7.67 and 6.20 respectively), TBA (1.981 and 1.845 meqO2/kg respectively) and FFA (0.95 and 1.22 % respectively) as chemicals and total muld and yeast (2.93 and 3.25 Logcfu/g, respectivly) as microbal communities (P<0.05). The results also showed that Halophillic and Anaerobic bacteria had higher and lower loads in smoked fish, respectively. While there were no differents in EPA and DHA fatty acids but most series like PUFA (30.35 and 19.67 g/100g), omega-3 (8.73 and 11.19 g/100g), omega-6 (21.52 and 8.49 g/100g) and w-3/ w-6 ratio (0.40 and 1.32) showed a difference between smoked Kutum and Golden Mullet, respectively (P<0.05). The results stated that chemical indices, nutritional values and microbal communities were in acceptable and freshness ranges in smoked products and their valuable fatty acid series were preserved.

Microbial Lipases are one of the most useful enzymes in various industries and the Lipase produced by Aspergillus niger fungus has a significant importance because of its product non toxin for usage in food and pharmaceutical industries. The production of the enzyme is affected by the conditions of its surrounding environment; thus, in this study the effect of two parameters of pH value and stirring rate in production of Lipase from Aspergillus niger source have been investigated with RSM method. The pH value of 7.5 and stirring rate of 190rpm have shown the best result in production of Lipase by submerged culture in medium containing date waste. Then the activity and stability of enzyme in different pH values and temperatures were investigated and the enzyme had its most activity in pH=7 while it is also stable in acidic conditions. The activity of Lipase was optimum in temperature of 30 Celsius and its activity is decreased in higher temperatures.

The main purpose of this study was to use wheat germ in production of milk dessert. Therefore, wheat germ was first heated at 150 oC for 15 min, then milled to obtain particle sizes of 125, 210 and 354 micrometers. Samples were made with 10% sugar, 2% gelatin and 88% low-fat milk (1.5% fat) and different levels of wheat germ (2.5, 5, 7.5 and 10%, w/w). Different characteristics of the fresh product and after storage for 15 days at 4 °C were determined. The results showed that with increasing the amount of wheat germ, dry materials of the samples increased while the pH decreased.Changes in the particle size of the samples had no effect on the dry materials. Textural evaluations showed that with increasing the germ level, particle size and storage time, hardness, cohesiveness, chewiness and gumminess, increased while elasticity decreased. Studying the internal structure of the desserts using scanning electron microscopy showed that the uniformity of the samples increased with increasing the germ content in dessert formulation. Moreover, with increasing the percentage and particle size of the germ, the darkness, redness and yellowness of the desserts increased. The results showed that the syneresis of desserts reduced with increasing the level of the germ, however, changes in particle size of the germ had no effect on this parameter. Sensory evaluation results concluded that the samples were prepared with maximum amount of 7.5% germ with particle size of 125 micrometer were the most acceptable samples.

Doogh is a traditional Iranian fermented milk drink, which is produced by lactic fermentation of pasteurized milk. In order to isolate and identify the microorganisms present in Iran industrial Doogh samples, polymerase chain reaction (PCR) was applied. Doogh samples were 17 name brands. After conducting the preliminary identification by microscopic observations and biochemical tests, in order to verify the obtained results the samples were pure-cultured which was followed by PCR and sequencing. According to the results obtained through sequencing of 16S rRNA, the identified bacteria belonged to lactic acid bacteria (Lactobacillus brevis, L. fermentum, L. paracasei and L. gallinarum); gram-posetive spore-forming bacteria (Bacillus licheniformis, B. anthracis and B. subtilis) and acetic acid bacteria (Acetobacter tropicalis and A. indonesiensis). Moreover, based on the results obtained by sequencing of D1/D2 26S rDNA the identified yeasts were including Pichia fermentans, Saccaromyces unisporous and Cryptococcus magnus. The obtaining of present study illustrated that in addition to identified non-starter lactic acid bacteria, other types of bacteria and yeasts were found in Iran industrial Doogh samples.