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Background and objective: In April 2002, a research group at Stockholm University and the Swedish Food Administration announced that significant amounts of acrylamide might be formed during common heat processing of foods. Since acrylamide is classified as “probably carcinogenic to humans” by the International Agency for Research on Cancer (IARC), these findings were considered as alarming. The most important food sources of dietary acrylamide are fried potato products like chips and French fries, which are popular snacks in Iran. The aim of this study was to investigate the effects of reducing sugars and amino acids in three potato cultivars on acrylamide formation in potato chips produced on a laboratory scale. Materials and Methods: Potato chips samples were produced on lab-scale from three potato cultivars namely Sante, Agria and Omidbakhsh by frying at 180 ºC for 4.15 min. Reducing sugars (glucose and fructose) and asparagine concentration in raw potato samples were determined using HPLC. A suitable and valid method was set up for determination of acrylamide in the chips samples by gas chromatography/mass spectrometry, GC/MS. Results: The reducing sugars and acrylamide contents were significantly different among potato chips samples produced from different cultivars (p<0.05). The highest amount of reducing sugars was found in cultivar Sante (3513 mg/kg) followed by Agria (2111 mg/kg) and Omidbakhsh (1622 mg/kg), respectively. On the other hand, cultivar Omidbakhsh had the highest amount of asparagine (1871 mg/kg). The highest amount of acrylamide (8825µg/kg) was formed in the chips from cultivar Sante and the lowest amount was formed in the chips from cultivar Omidbakhsh (5112 µg/kg). Conclusion: A high content of asparagine in raw potatos was not necessarily an indication of high content of acrylamide in the produced chips. The two cultivars with higher content of reducing sugars, showed the higher potential for acrylamide formation in the chips. This indicates that the concentration of reducing sugars is a more important parameter than asparagine content in the formation of acrylamide in potato chips. The selection of proper potato cultivars with naturally lower contents of precursors of acrylamide specially reducing sugars is important factor to reduce the acrylamide formation during production of potato chips. With respect to the results obtained from this study, it is suggested that cultivar Omidbakhsh is the most suitable cultivar in Iran for the industrial production of potato chips with low levels of acrylamide.

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Background and objectives: Mycotoxin contamination of agriculture commodities is a serious concern as regards human and animal health. Rice is a staple food and one of the major carbohydrate sources in the diet of Iranian people. There are reports on the contamination of rice with mycotoxins such as aflatoxins, citrinin, deoxynivalenol, fumonisins B1 and B2 , fusarenon-X, nivalenol, ochratoxin A, sterigmatocystin, and zearalenone. In the present study, 100 samples of rice sold in several branches of three of the main chain stores in Tehran, Iran were collected and analyzed for ochratoxin A (OTA). Materials and methods: Ochratoxin A was extracted from the samples with acetonitrile-water solvent and purified using the immunoaffinity column. HPLC with fluorescence detector was used to identify and measure the OTA, the detection and quantification limits were being 0.03 and 0.1 µg kg-1 respectively. Results: The OTA content in all the 100 imported and domestic rice samples was 69%. The mean and range of OTA were 1.37±5.72 and 0.15- 46.79 µg kg-1, respectively. In the most samples OTA contamination were lower than the permitted thresholds in cereals according to the Institute of Standards and Industrial Research of Iran (ISIRI) standards. Conclusion: Considering the high contents of OTA in some of the rice samples on the one hand, and the high consumption of other foods contaminated with OTA on the other hand, the total intake of this toxic substance may exceed its Provisional Tolerable Daily Intake as determined by the Joint FAO/WHO Expert Committee on Food Additives. In order to control mycotoxin contaminations, taking pre- and post-harvest preventive measures (GAP, GHP, GSP, GMP and HACCP), as well as sharing experiences and collective effort of all the parties involved, are highly essential.

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Background and Objectives: Walnut green husk is one of agricultural residues that can be considered as natural compound with biological properties because of its phenolic compounds. In the present work, the goal is extraction of aqueous extract of green walnut skin and studying the effect of extraction temperature on the phenolic compounds and antioxidant and antimicrobial properties of extract. Meanwhile, the effects of spray dried encapsulation process of extract in maltodextrin on the biological activity of extract are investigated.

Materials and Methods: In this study, walnut green husk (Sozani variety) was extracted in two temperatures of 25 and 80 °C. Then it was encapsulated in 10% maltodextrin in three different concentrations of extract (0.5, 1 & 2 mg/ml) using spray drying method. Total phenol of the extract was evaluated before and after encapsulation. In addition, the antioxidant activity of the aqueous extract of walnut green husk was determined before and after microencapsulation by the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals. Antimicrobial activity of the extract was determined by Agar well Diffusion Method against gram positive (Bacillus cereus, staphylococcus aureus) and Gram negative bacteria (Escherichia coli, Salmonella Typhimurium).

Result: It was revealed that the effect of extraction temperature on total phenolic compounds was significant (p<0.05). The samples extracted in 80°C had more phenol components (39.77 mg GAE/g) than the samples extracted in room temperature (28.88 mg GAE/g). Encapsulation efficiency was increased by increasing the extract concentration. The 2 mg/ml concentration of free and microencapsulated extract obtained at 80 °C had the highest scavenging effect on the DPPH radicals (85.05 & 81.05%, respectively). In addition, 2 mg/ml concentration of free and microencapsulated aqueous extracts of walnut green husk showed the highest inhibitory effect against Gram-positive bacteria. The results further showed no significance differences in the antioxidant and antimicrobial activities of free and microencapsulated aqueous extracts of walnut green husk.

Conclusion: Sozani walnut green husk can be used as a cheap source of antioxidant and antimicrobial compounds due to having high amount of phenolic compounds. Therefore, microencapsulation can be used as an efficient method for increasing the stability of walnut green husk extract against the environmental conditions.

Keywords: Walnut green husk, Aqueous extracts, Antimicrobial activity, Antioxidant activity, Microencapsulation

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Background and Objective: In this study, given the increasing importance of meat production such as burgers in the country, the quality of these products is of utmost importance. With the aim of producing better quality hamburgers , the effect of amaranth grain flour as a substitute for soy protein flour and breadcrumbs in a typical hamburger formulations were studied.

Materials and Methods: In this study, half (50%) of the flour with amaranth Replaced instead of soybean protein powder and toasted flour, and chemical properties (protein, ash, moisture, pH), sensory and weight loss of Amaranth containing samples and control sample were compared.

Results: Based on the results of chemical tests, with partial substitution of soybean protein and toasted flour, the pH, moisture and weight loss contains amaranth changed from 6/06, 56/16, 9/80 to 6/13, 57/33, 5/53 percent, respectively, without significant changes in protein and ash. The results of sensory evaluation showed that except for the odor and color samples, other sensory characteristics were not under the effect of reducing the amount of soy flour and toasted flour, in the burgers formulation.

Conclusion:  The results of this study showed application of amaranth flour in production of typical meat hamburger lead to new product with good sensory properties that is acceptable for consumers.

Keywords: Burger, Amaranth, Amaranth flour, sensory characteristics, weight loss

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Background: composite films which are consisted of edible and synthetic components are introduced as a novel idea in food packaging industry. Because of different nature of these components, it is problematic to use them in a composite film without any modification on polymer surface. In this study, plasma treatment was used to modify polypropylene (PP) surface and then it was coated by carboxymethyl cellulose (CMC). 

Material and methods: In this study, physical, mechanical and water vapour permeability of bilayer films (PP/CMC) were compared with individual PP and CMC films. In order to perceive the effect of plasma treatment on the properties of bilayer films, a comparison was also done between treated and untreated bilayer films.

Results: Plasma treated PP/CMC films had lower water vapour permeability and better mechanical properties compared to untreated bilayers, individual PP and CMC films.

Conclusion: Application of plasma treated PP/CMC films could have an important role in improvement of barrier and mechanical properties of food packaging.

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Background and Objectives: Problemsof poor organoleptic and physicalproperties of low fat cheese suggest the use of some hydrocolloids in providing the desirable qualities of these types of cheeses.To improve the characteristics of low fat cheese, several studies have been used polysaccharides as fat replacers.In this study, for improving the characteristics of low fat Iranian white cheese, gum tragacanth (Astragalus Parrowianus) was added to the low fat cheese milk in two level (0.05 and 0.1% (w/w).
Materials and Methods: Changes in physicochemical, textural, sensory and microstructural properties of cheese samples in day 1 and 60 of ripening time were evaluated and a comparison between cheese samples containing gum and blank samples (full fat and low fat cheeses) was carried out. For better investigation of interactions between protein and polysaccharide in cheese matrix, FTIR method was used.
 Results: Addition of gum tragacanth into low fat cheese matrix resulted in a better texture and structure and could relatively imitate the full fat cheese characteristics. Incorporation of this gum caused some changes in FTIR spectra of low fat cheese. Ripening time also influenced the FTIR spectra of cheese samples.
Conclusion: Incorporation of gum tragacanth into low fat Iranian white cheese, can improve its textural, sensorial and microstructural characteristics. FTIR can be a proper instrument for precise studying of protein matrix of cheeses.

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Background and Objectives: Aloe vera plant mainly grows in dry areas due to having abundant medicinal and nutritional properties, can be used as a natural food additive. This research aims to determine the impact of aloe vera gel powder in tissue (texture) and shelf life of sponge cake, so that more beneficial products with better tissue quality can be produced.
Materials & Methods: Aloe vera gel powder was added to the flour in three levels of 2, 4 and 6% compared to the regular cake flour, then water absorption properties and rheological characteristics of dough was measured. In the next step, the cakes are prepared with the desired size, then histological characteristics can be measured. The sensory characteristics and microbial properties of produced samples are then compared to the control. .
Results: The results indicated that Aloe vera gel powder controls the activity of the microorganisms, mold, and yeast in sponge cakes during maintenance, therefore it has anti-bacteria properties. Results The Aloe Vera powder has been shown to control the activity of microorganisms, mold and yeast in a sponge cake during storage, thus having antimicrobial properties. The results of the texture properties of the cakes indicate that the firmness of the samples containing 2% of the Aloe Vera powder was reduced during storage, adding the powder increased the brightness and redness of the colored cakes at 2 and 4 percent. In evaluating sensory evaluations, there was a significant difference between the form, the form and the overall acceptance, which obtained the highest score in the overall assessment of 2%.
Conclusion: In General, the positive effect of Aloe Vera gel powder on improving the properties of dough and cake samples, it is recommended to be combined with food such as sponge cake to improve the quality and increase the nutritional value of the product
 

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Background and Objectives: In beverages industry, clarification is one of the unit operations that it is used to remove the color, aroma and undesirable flavor, haziness, bitterness and acridity.
Materials and Methods: For clarification of celery juice, different clarification methods such as mechanical (I), bentonite earth (II), active charcoal (III) and gelatin (IV) were used. Then, in each of the studied methods, the processing parameters including the concentration of compounds, rotation and process time were optimized by RSM approach.
Results: After optimization process, the optimum points for methods I, II, III and IV were obtained as (3999.5 rpm and 14.77 min), (500 ppm and 25 min), (1418.37 ppm and 81.17 min) and (105.89 ppm and 119.48 min), respectively. Type of clarification method had significant effect (p<0.05) on the transmittance index of produced celery juice, and the amount of transmittance in different clarification methods I, II, III and IV was 8.71, 1.965, 0.477 and 31.31%, respectively; the loss of cholerophyll pigmenty corresponding to each of these methods comparing to the blank sample was computed as 65.37, 41.64, 16.84 and 86.24%, respectively. The lowest amount of pH (5.69) was observed in method IV, which corresponds to the greatest acidity value. Also the change of specific gravity was very trivial and the lowest amount of it was related to method IV (SG=1.0114), most probably due to the loss of suspension particles present in celery juice.
Conclusion: Goodness clarification methods of celery juice in order of importance included IV, I, II and III. Generally, application of clarification method IV as the best treatment is recommended for the processing factories of this crop.
 

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Background and Objectives: Cold plasma is an eco-friendly and non-thermal technique, which has become an important technology to change the physical and chemical features of polymers. Recently, cold plasma has been considered in the decontamination and modification of packaging materials in the food industry. Therefore, the objective of this study was to survey the effect of using low-pressure oxygen plasma treatment on the surface and physicochemical properties of starch-chitosan composite films.

Materials & Methods: The low-pressure oxygen plasma treatment of starch-chitosan composite films was carried out using a plasma cleaner system at various times (4, 8 and 12 min). Afterwards, the surface properties and physicochemical properties of untreated and plasma-treated films were compared.

Results: The surface roughness and hydrophilicity of the films were increased after tlasma treatment. The tensile strength of the plasma-treated films was improved. Plasma treatments decreased the oxygen permeability of the films but no significant change in their water vapor permeability was observed.

Conclusion: In this study, although plasma treatment increased the tensile strength and decreased oxygen permeability of the films, their surface hydrophilicity was increased too. There is a need for further studies to modify the starch-chitosan composite film by plasma treatment.
 

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Background and Objectives: In recent years, consumers demands for ready meals such as hamburgers have increased due to changes in human lifestyle. In low-meat hamburgers, replacement of meat with soy protein can make problems such as dryness, brittleness, darkness and undesirable taste of hamburgers. Soy, often used in these products, is one of the most important allergic compounds that limits options of the allergic consumers. The aim of this study was to replace soy protein powder and bread crumbs with quinoa and buckwheat flours in low-meat hamburgers.
 Materials & Methods: In this study, 30 g of each quinoa and buckwheat flour were used as soy protein and breadcrumb replacers in hamburgers with 30% meat. Chemical properties, emulsion stability, cooking properties, texture and color of low-meat hamburgers formulated with quinoa and buckwheat flours were compared with those of control sample.
Results: No significant differences (p > 0.05) were observed in cooking properties and water activity between the hamburgers formulated with quinoa and buckwheat flours and the control sample. Furthermore, L* (lightness) was significantly higher and a* (redness) lower in raw hamburgers formulated with quinoa. In control sample, emulsion stability and texture properties were significantly higher (p < 0.05).
Conclusion: Based on the results, this replacement may be appropriate in cooking properties, water activity and color for low-meat burgers.

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Background and Objectives: Celiac disease is an autoimmune disease caused by the digestion of gluten. The unique treatment of this disease includes use of diets with no gluten. Carrot pomace is a byproduct of juice factories, which is rich in minerals. The aim of this study was to assess effects of carrot pomace powder on physicochemical and sensory properties of gluten-free cakes and comparison of these cakes with rice and wheat cakes.
 Materials & Methods: D-optimal mixture design approach was used to prepare optimal carrot cake samples based on the volume. The optimal cake samples were compared with those prepared from rice and wheat flours for chemical properties, dough viscosity, baking properties, texture, color and sensory characteristics.
Results: Complete replacement of carrot pomace powder showed significant differences in humidity, water activity and porosity of the samples. Carrot pomace powder cakes included significantly lower L* (lightness), a* (redness) and b* (yellowness) values than those the rice and wheat flour cakes did. Wheat cakes were significantly larger than the other cakes and the lowest volume belonged to rice cakes. Hardness of the wheat flour samples was less than that of gluten-free samples. In sensory characteristics, carrot pomace powder cakes included significantly higher overall acceptance scores, compared to those wheat and rice cakes did.
Conclusion: Based on the results from this study, the highlighted replacement may positively affect physicochemical properties of the gluten-free cakes.

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Background and Objectives: Bioactive packaging systems (coatings/films) are novel technology concepts in food industries. Bioactive compounds such as antioxidants, vitamins, probiotics and prebiotics are designed to be included in coatings or coating materials that directly affect health of consumers. The aim of this study was to assess feasibility of producing prebiotic edible films by adding inulin to the film based on carboxymethyl cellulose and beta-glucan and to investigate film mechanical, barrier and structural characteristics.
 Materials & Methods: In this study, various concentrations of inulin (0, 2 and 4% w/v) were added to carboxymethylcellulose/beta-glucan solutions. Then, mechanical (tensile strength and elongation at break), barrier (oxygen and water permeability), optical (opacity, a, b and L) and structural characteristics of the films were compared with each other.
Results: Inulin included plasticizing effects in all treatments. Thus, tensile strength decreased and hydrophilicity, oxygen permeability and elongation at break increased significantly (p < 0.05). Fourier-transform infrared spectroscopy analysis showed that hydrogen bonds were the major force between carboxymethylcellulose, beta-glucan and inulin, which increased flexibility and water affinity of the films.
Conclusion: Although addition of inulin improved composite films via increases in elongation at break and decreases in oxygen permeability of the composite films, their hydrophilicities increased as well. Therefore, these films include the potentials in cases, where packaging hydrophilicity is an advantage such as edible coating used in food products. However, further studies seem necessary.

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Background and Objectives: Nowadays, interests in ready-to-eat foods, especially ordinary burgers, have increased. To produce typical burgers, breadcrumbs and soybean meals are commonly used as fillers. Use of breadcrumbs and soybean meals in regular burgers limits choice of consumers with allergies. The aim of this study was to produce typical hamburger products by replacing breadcrumbs and soybean meals, which could be used by people with celiac disease and sensitivity to soy protein.
Materials and Methods: In this study, mixtures of breadcrumbs and soybean meals respectively decreased by 50 and 100% and similar quantities of teff flour were substituted for these mixtures in low-meat hamburgers. Then, physicochemical, sensory  and cooking characteristics of treatments containing teff flour were compared with those of control sample.
Results: The control sample included the highest cooking yield (92.45%) and the lowest moisture retention (68.87%) and TF100% treatment (31.10%) included the lowest oil absorption within all samples (p < 0.05). Samples containing teff flour received a higher score in the characteristics of smell and color. In sensory evaluation no significant differences were observed between the samples in terms of texture, taste and overall acceptance (p > 0.05).
Conclusion: Results of this study showed that replacing breadcrumbs and soybean meals with teff flour in low-meat hamburgers could be appropriate in terms of decreasing fat absorption and improving moisture retention and sensory and

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