IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2017 | Volume:14 | Issue:70|Papers Count:32

With respect to the human need for functional food and the importance of long-chain polyunsaturated fatty acids as a functional food, identifying the rich resources of fatty acids greatly attract of interest of scientists. Based on this studies, it is found that microorganisms especially yeast species are rich resources of unsaturated fatty acids. In the present study, yeast samples of perch fish, which has the ability of oil production, were isolated and then their ribosomal DNA were used to identify the yeast species. According to the phylogenetic tree, it was known that the yeast species isolated from the gills of perch fish was Candida Orthopsilosi SAKSG. The response surface method showed that the highest oil content (26.3) was achived in media that had 50 g/L glucose and 5 g/L yeast extract. Moreover, maximum amount of biomass (1.16%) was obtained in medium with 46.16 g/L f glucose and 19.67 g/L yeast extract. It is notable that reduction in temperature treatment was led to improve unsaturated oil increment in this microbial lipid up to 24 percentages. reduction of temperature at the end of the fermentation time concide with rising in unsaturated fatty acids with long fatty acid more than 20 carbon, while when temperature was increased from the beginning of the process, structural unsaturated fatty acids such as linoleic and linolenic acid were increased.

Every year large amount of oil seeds are produced from plant sources. However this process produces large amounts of oil cake with high amounts of protein and essential amino acids. On the other hand the disposal of this by-product is a big problem. So in the present research the protein from defatted pumpkin seed flour was extracted and the nutritional properties of its protein isolate Were investigated. The protein solubility profile of defatted pumpkin seed determined as a function of pH between pH 1-12. Also the effect of NaCl concentration of 0.1, 0.5, and 1 M and pH 8, 9, 10, 11, 12 on protein solubility was determined. Pumpkin protein isolate was prepared from defatted pumpkin flour through the alkaline extraction and isoelectric precipitation. Chemical composition (protein, fat, ash, carbohydrate and water contents) of pumpkin protein isolates and defatted pumpkin seed flour were determined. In addition the nutritional characteristics of protein isolate were studied. The results showed that the solubility at acidic pH values decreased And the isoelectric point at least seems and then increased in basic pH values, and then solubility reached to maximum level at pH 10. The effect of salt concentration on protein solubility was significant at the 5% level (P<%5) and increased salt had the opposite effect on protein solubility Nutritional value of pumpkin protein isolate was high and could be used as a good source of essential amino acids. Considering the high nutritional content of protein isolate of pumpkin, it can be used for improving nutritional content of different food product.

In this research work, in order to estimate the drying properties of eggplant and turnip in a combined microwave-convection dryer it was used artificial neural network method in order to estimate the Drying process was accomplished in three temperature levels (40, 55, and 70 °C), three inlet air velocity levels (0.5, 1.1 and 1.7 m/s) and three microwave power levels (270, 450 and 630 W) in a combined microwave-convection dryer that the three parameters were utilized as input in predicting the effective moisture diffusion coefficient and specific energy consumption in artificial neural network. A feed forward and cascade forward back propagation neural network with training functions of Levenberg -Marquardt (LM) and Bayesian Regulation (BR) for training of patterns. According to results, the highest value of the effective moisture diffusion coefficient for eggplant and turnip was obtained 3.39×10-9 and 3.05×10-9 m2/s, respectively. Results of ANN investigations showed that the optimum feed forward back propagation network with 3-20-20-2 topology and training function of Levenberg –Marquardt could predict the effective moisture diffusion coefficient and specific energy consumption with determination coefficients of 0.9821 and 0.9952 and mean square error of 0.00014 in various drying conditions of eggplant and turnip. Also the highest determination coefficients for prediction of drying rate and moisture ration obtained 0.9698 and 0.9988 with the value of mean square error of 0.0045 in cascade back propagation neural network with training algorithm of Levenberg –Marquardt.

Junk food consumption and low nutritional value is the main reasons for the prevalence of malnutrition among Iranian children. So enrichment of these foods is one of main goal of food researcher. Therefore in this study quinoa, amaranth and buckwheat flour in levels of 5, 10 and 15% was used as rice flour replacer in gluten free cookie for high nutritional value. Nutritional, textural, visual and sensory properties of sample were evaluated in completely randomized design (p£0.05). Results was indicated by adding semi cereal and increasing the level in cookie formulation, protein, ash, moisture, softness of texture in 2hr and one week after baking were increased. Also the results of image processing showed buckwheat and amaranth respectively increased the amount of a* and b* values of gluten free cookie surface. Finally sensory evaluation showed the samples containing 10 and 15% quinoa and amaranth had the best score of overall acceptance. So these samples can be supplied to the consumer market of celiac disease and any gluten sensitivity as a fortified gluten free product.

Today The correct choice of an alternative type of fat replacer in low-fat products is very important. Because In addition maintaining the technological characteristics, the price of the product is less than or equal to the whole sample. Therefore the melon seed flour as a agricultural waste and fat replacer was used in levels of 5, 10 and 15% to replace full-fat in biscuit. However, in this study in addition of melon seed flour, the application of lecithin emulsifier in 0.1, 0.2 and 0.3% were investigated and compare to the control sample (without melon seed flour and lecithin emulsifier). Based on the results, by replacing fat in the biscuit formulation the amount of fat and moisture of final product were reduced and the amount of ash, protein and hardness were added. While the lecithin reduced firmness and increased the moisture content. It should be noted that the sample contained 10% melon seed flour and 0.3% lecithin was equaled to control in texture hardness. The results showed that the melon seed flour was effective in reducing the L* value and increasing b* value. In addition, sensory evaluation indicated the sample containing 10% melon seed flour and 0.3% lecithin emulsifier had the best score in color, flavor and texture. Therefore we can say that melon seed flour especially in the level of 10% in addition to 0.3% of lecithin emulsifier capable replacement of existing whole fat in biscuit and production low-fat product.

The aim of this study was to identify and then, evaluate the probiotic potential of the strains that isolated from local yogurt drink (Doogh) in Torghabeh, Mashhad. Nine local Doogh samples were collected and morphological and biochemical tests including Gram staining, catalase test, growth at 10 and 45 °C, Carbon Dioxide gas production from glucose, growth at concentrations of 6.5% NaCl, growth at pH 4.4 and 9.6 and hydrolysis of arginine to identify in genus level was performed. With using carbohydrate fermentation profiles, isolates were classified and sequencing of 16S rRNA gene was performed on selected isolates. These 87 strains were belonged to Lactobacillus (plantarum, acidophilus, delbrueckii subspbulgaricus and casei subsp casei), Lactococcus lactis (subsp. lactis and subsp. cremoris), Enterococcus(faecium and durans) and Leuconostoc (mesenteroides) respectively. To evaluate the probiotic characteristics of strains, resistance to pH (2.5 and 3.5), bile salt (concentration of 0/06, 0/125 and 0/5 %), and the antibacterial property of the isolates were performed. Finally, from these 25 isolates, Lactobacillus(plantarum and acidophilus) and Enterococcus faecium showed good probiotic properties, although the most probiotic potential belonged to Lactobacillus plantarm (AL35). The results of this study showed that isolates have high antibacterial activity. Therefore, considering the side effects of antimicrobial compounds and chemical industries, these microorganisms can be used as natural preservatives in various food products.

Bread as the cheapest source of energy and protein feed much of the world is critical. Today, due to consumers on the nutritional characteristics of foods, functional foods and beneficial use has increased. One of the foods by FAO has been introduced as a functional food is quinoa. Quinoa is a gynomonoecious plant and is known as a pseudo-cereal. The seeds of the Latin American people have been used 5000 years ago. Quinoa protein and essential amino acids such as lysine and methionine, essential fatty acids (W6) and unsaturated fatty acids, minerals such as iron, calcium, zinc and copper, dietary fiber, vitamins and antioxidant substances from other common grains such as wheat, barley and rice is better. Response surface methodology (RSM) with a 5-level-2-factor central composite rotatable design (CCRD) was employed, where the independent variables were Xanthan gum (0-1.5%), quinoa whole flour (0-15%) while the dependent variables were surface sensory properties, moisture, ash, fat, protein of Barbari bread. The results showed that by adding quinoa whole flour to bread flour ash, protein and fat were significantly increased, adding xanthan gum to increase the amount of moisture in the bread samples. Also it was revealed that all traits were significant at 95%. Therefore, the model has been approved for fitting information. The model proposed in this study R2 and R2 (Adj) are fit and highly significant. The lack of fit test is also meaningless and coefficient of variation is low, which shows that provided model is suitable for predicting assessed parameters. The optimal point for the formulation of 9.84% quinoa whole flour, and 1.5% xanthan gum.

Validating for detecting aflatoxin M1 in yoghurt according to Commission Decision BS EN ISO 14501: 2007. In this study yoghurt samples prepared with milk powder without aflatoxin (Made in Holland) and then artificially contaminated by adding aflatoxin M1. Analytical method using immunoaffinity column for extraction and a high-performance liquid chromatography (HPLC) with FLD detector for quantification was performed according to the device settings. To achieve the best possible condition to identify and ensure the separation of aflatoxin M1, deploying some important device control such as, control the flow of the mobile phase and the mobile phase constituents was applied. The procedure for determining selectivity, recovery, precision, decision limit (CCa) and detection capability (CCb) of the method has been reported. The method includes a preliminary clean-up and the average recoveries determined on three different days at the concentration levels of 0.025, 0.050 and 0.075mg kg⁻¹ were in 74.28%, 80.89 and 86.77% respectively with RSD in the range of 2.56%-8.41%. The interday and interlevel mean recovery value, which has been used to correct routine analysis results, was 80%. The method is rapid, easily automatable with low retention time and high accuracy therefore useful for accurate and precise screening of aflatoxin M1 in yoghurt.

Celiac disease is an autoimmune digestive disease that is caused by gluten protein digestion, and the only way to treat it is using a gluten-free diet. Thus, paying attention to the production of gluten-free food with the quality that is acceptable for these patients has a significant importance. Therefore the aim of this study was to evaluate the effect of adding purslane flour at four levels of 0, 10, 15, and 20 percent by weight (based on rice flour) and its effect on various properties of gluten-free flat bread. The results of chemical tests showed the increase in the amount of moisture, ash, protein, fat, fiber and pH in the samples containing purslane flour compared to control samples (without purslane flour) showed. Also, farinographic test results showed that by increasing the percent of purslane flour, the flour water absorption, the time of dough stability, the time of dough expansion and valorimetery index were increased and the degree of dough loosening was decreased. Also The results obtained by Instron and feel at intervals of 48.24 and 72 hours after baking showed that treatment with 85% rice flour and 15% flour Purslane has the least staling and most points lately and control the highest amount stale and Recently had the lowest score. The color components * a * b * determined that the sample bread L with 10 percent of the rest of the flour purslane better color formulations. The best treatments treatment) C2 bread flour containing 85% rice flour and 15% purslane) was introduced.

The most common methods of extraction of oil from oils seeds are pressing and solvent methods that the most effective method of extracting sunflower oil, like other seeds with high oil content such as rapeseed, is mechanical press and then solvent extraction. In this research, to model the process of oil extraction from sunflower seeds on an industrial scale, three levels cooking temperature (70, 80 and 90 oC) and three levels of moisture of the output seeds from the cooker (7, 7.5 and 8 %) was used and the amount of oil acidity, the contentt of oil, protein and moisture of meal and the percentage of insoluble fine partical in oil were studied. To predict the changes' trend the artificial neural network in MATLAB R2013a software was used. By studying the various networks of back propagation feed forward network with topologies 2-10-5 with a correlation coefficient of more than 0.999 and the mean squared error of less than 0.003 and with using sigmoid hyperbolic of tangent activation function, the Levenberg–Marquardt learning algorithm and learning cycle of 1000 were specified as the best neural model. The results of the optimized and selected models were evaluated and these models with high correlation coefficients (over 0.96), were able to predict the changes' trend.

Omega-3 fatty acids are a large group of polyunsaturated fatty acids. Docosahexaenoic acid, the most important omega-3 fatty acid, has beneficial effects on human health. The aim of this study was to convert flaxseed oil by native strain of Aurantiochytrium to omega-3 oil rich in DHA and linolenic acid.At first, lipase production and its activity was measured in broth medium. Production of biomass and oil in medium containing amounts of flaxseed oil were determined. Also, saturated and unsaturated fatty acids were determined by gas chromatography. Aurantiochytrium strain produced precipitated halozone after 48 hours incubation in lipase production medium with a diameter of 6 mm. Lipase activity of 150 units per ml was measured in medium containing 1% of flaxseed oil. atty acids oil in basal medium without flaxseed oil was including C14, C15, C16, C17, C18, C18: 1, DPA and DHA. By adding flaxseed oil to the basal medium, biomass was increased to 15.7 g/l. The greatest amount of DHA (388 mg/l) and oil content (53.25%) was obtained in medium containing 0.6% of flaxseed oil. In conclusion, by increasing the concentration of flaxseed oil in medium, the amount of saturated fatty acids was decreased and mono or polyunsaturated fatty acids were increased. Also, fatty acids profile of oil produced in flaxseed oil medium was including C18: 2, C18: 3, DPA and DHA. Finally, produced omega-3 oil was contained DHA, linolenic and oleic acid and can be used to enrichment foods and dairy products.

The carob moth, Ectomyelois ceratoniae (Zeller) and various diseases are the main limiting factors of postharvest life of pomegranate fruit. Including effective treatment to reduce pests and diseases of agricultural crops is gamma radiation. The effect of this treatment in reducing postharvest pests and diseases of pomegranate fruit has been also shown; however, its effect on fruit quality during cold storage has not been investigated. In order to study the effect of gamma irradiation on pomegranate quality this study, as factorial in frame of CRD, was conducted at Shahed University and Nuclear Agriculture Research School in 2015. For that pomegranate fruits cv. ‘Malas Saveh’ were harvested at maturity stage and treated with gamma radiation at doses of 0, 1, 3, 5 and 7 kGy and were stored at 6oC with 80% RH, and then were taken on 1, 2 and 3 months of storage. Results showed that application of gamma radiation in comparison to control increased weight loss and electrolyte leakage, and reduced soluble solid, total phenol, anthocyanin and vitamin C contents as well as antioxidant capacity. Nevertheless the effects of treatments at low doses, especially at 1 kGy, were not considerable, but fruit quality decreased more with increasing doses. Therefore low doses of this treatment can be effectively use in increasing postharvest life of pomegranate fruit.

Today because of the direct relationship between diet and the risk of cardiovascular disease, obesity and colon cancer has increased consumer demand for low-fat foods. So in this study the effect of adding quince seed gum on level of 0, 1.2, 2.4, 3.6 and 4.8% and reducing the amount of fat, on physicochemical and textural characteristics of hamburger including lipid oxidation, free radical scavenging, shrinkage, moisture retention colour and texture during the 9 days of storage at 4oC was studied. The results showed that adding gum significantly reduced shrinkage of treatments in comparison with control sample (P˂0.05). Also moisture retention and antioxidant property of treatments significantly increased in comparison with control sample (P˂0.05). Use of quince seed gum had no significant effect on redness a*/b* of raw hamburgers, while redness of fired-hamburgers decreased compared to control sample(P˂0.05). The texture results showed that adding quince seed gum was increased stiffness of treatments significantly (P˂0.05). The results of this study showed that can be used quince seed gum as a suitable fat replacer in hamburger formulation.

Hydration of Emulsifiers and production of gel emulsifiers increases performance of them in bakery industry. The aim of this study was to investigated the effect of different concentration of DATEM (5, 10 percent) and distilled monoglyceride (50, 60percent) and constant level of polyglycerol ester (10percent) in gel emulsifier formulation on physicochemical properties of batter (pH and viscosity) and physicochemical and rheological properties of cup cake (color, specific volume, texture and moisture content). experiments was investigated in a completely randomized design in 3 replications (a=95%).The result showed that the best concentration of DATEM by 50 percent of monoglyceride was 5 percent. These gel Formulation was decreased Viscosity of batter, moisture content (1 week after cooking), hardness of Cake and and a* and b* of crumb of Cake and increased PH of batter, specific volume of Cake and L* of crumb and crust of Cake. As well as the appropriate concentration of DATEM by 60 percent of monoglyceride was 10 percent. also these gel formulation was increased Viscosity of batter and decreased PH of batter also these gel decreased moisture content (1 week after cooking) and hardness of cake and a* of crumb of Cake. increased L* of crumb and crust of cake and b* of crumb of Cake.

This study conducted to compare the effects of sodium tripolyphosphate, sodium hexametaphosphate and tetrasodium pyrophosphate on some physico-chemical characteristics of cured beef round, before and after cooking. For this purpose, after preparation of round cuts of beef and injection of curing solution containing 0.5% of the studied phosphate (including sodium tripolyphosphate, tetrasodium pyrophosphate and sodium hexametaphosphate) each one alone or in combination with two types of these phosphates in equal proportions (0.25%+0.25%) were produced in the form of six treatments which followed by ripening, forming and cooking processes and also cured phosphate-free thighs were considered as control. Then, all specimens were stored for 30 days at 4 °C and physicochemical tests (including pH, WHC, texture and cooking loss) conducted before and after cooking in 1, 15 and 30 days of storage time. The results showed that treatments of cured round beef containing sodium tripolyphosphate and tetrasodium pyrophosphate each one alone increased the pH and WHC significantly, both before and after cooking. Moreover, these two samples showed the lowest cooking loss and featured a better texture. But control sample and treatment with sodium hexametaphosphate did not show the desired results in these studied properties, respectively.

Type of baker's yeast and fermentation time, are two factors that affect the quality of fermentation in bread dough. In this paper, with seven samples of instant dry yeast, gas powering of yeast was examined with gasography method. Also the interaction between the yeast and fermentation time on the production of Carbone dioxide has been investigated. Maximum amount of carbon dioxide produced by yeast A (163.33 ml) and yeast G had the least amount of gas production (139.67 mL). Investigation on fermentation time showed that the All times are significantly different at the 5% level, but from 165 minutes to 180 this difference was not significant. The study of interactions of yeast and fermentation time on the production of carbon dioxide by seven samples of yeast showed that at the same fermentation conditions, the type of yeast and fermentation time had a definite effect on gas powering of bakery's yeasts.

Lysozyme- chitosan-cumin oil films were develop for enhancing the antimicrobial properties of chitosan films. A different concentration lysozyme solution was incorporated in to chitosan 2% film forming solution and 1% oil cumin. The film used for microbial properties of chicken fillets stored at refrigerator. Lysozme and cumin oil releases from the matrix of chitosan film and effect on antibacterial properties such as total mesophilic bacteria, microbial Total bacterial count, Psychrophiles, Coliforms and Pseudomonas. Results showed that 10% lysozyme and 1% cumin oil enhance the efficiency of chitosan film against bacteria in chicken fillet. Statistical results showed that 3 log cfu/g reduced in mesophilic bacteria in 12 days and 3 log cfu/g, 1.1 log cfu/g, 3 log cfu/g in Psychrophiles, Coliforms and Pseudomonas bacteria respectively. So the results showed the synergistic effect of oil cumin and lysozyme in to chitosan –based films. Thus brooding their application enhancing food quality and saftely.

With regard to possibility of the acrylamide carcinogenicity, increasing expansion of fried potato products industry and high consumption of these products in the country, the study and modeling of phenomena involved in the process of these products are seems necessary. The aim of this study was to investigate the kinetics of decreasing of reducing sugars, acrylamide formation and color changes during frying of potato strips. The results showed that decreasing of reducing sugars and acrylamide formation are occurring with the exponential patterns during frying and increasing temperature and time of frying are intensifies these phenomena significantly (P<0.05). On the other side increasing of frying temperature was decreased the darkness-lightness index and was increased the redness greenness and yellowness-blueness indexes significantly (P<0.05). The darkness-lightness and redness-greenness indexes were increased (P<0.05) with increasing of frying time initially and were remained almost constant afterwards, while the yellowness-blueness index was increased (P<0.05) linearly with frying time increasing. The results also showed that the exponential kinetic have the most conformity with experimental data of reducing sugars decreasing and acrylamide formation. Based on the results darkness-lightness and yellowness-blueness indexes changes during frying are follow the first order kinetic with production rate limiting effect while the zero order kinetic was showed the most conformity with redness-greenness index changes.

Juices are kinds of popular beverages in world but are poor in term of fiber content. Generation of food products which contains relatively high amount of dietary fiber, due to its healthy properties, remains a challenge because of negative effects of dietary fiber on appearance and stability of these products. In this study, stability of fruit based beverages containing different percent of basil seeds, as a dietary fiber source, was evaluated. Gum Tragacanth (GT) and Carboxymethyl cellulose (CMC) was used for stabilized seeds. Then change in stability of beverages during time was evaluated by measuring of zeta potential, rheological properties, height percent of seeds and color changes. Results showed that GT was more effective than CMC for preventing sedimentation of seeds, although zeta potential of CMC was higher and consistency index of both hydrocolloid was similar. However existence of GT in samples caused to darkening of the color samples but CMC had not effect on color.

Bacteriophage is the phage which causes the microbial host to infect and coliphage is the bacteriophage which in fects Escherichia coli. The presence of coliphage in surface waters is the indication of fecal contamination (enteric viruses). The objective of this study was evaluation of enteric viruses recovery from farmed fish using Male specific coliphage (MS2) as an indicator bacteriophage for enteric viruses due to stable connection to surfaces. MS2 coliphage was used to contaminate farmed Salmon fish in three concentrations (103, 105 and 108 pfu/ml) all around Mashhad city. After phage spiked, Coliphage recovery was evaluated using double agar layer technique from three different parts of Salmon fish (gills, skin flesh and interceptive) according to the best procedure (glycine- threonine- polyethylene glycol). The highest coliphage recovery in the lowest spiked concentration (103pfu/ml) was in skin-flesh of Salmon fish while interceptive of Salmon fish had the highest recovery in 105pfu/ml of spiked concentration.

In this laboratory study, the optimization process of ultrasound-assisted extraction (UAE) of phenolic compounds of Ziziphora clinopodioides was done using response surface methodology (RSM). For the determination of total phenolic compounds and antioxidant activity of the extracts, Folin test and DPPH assay were used, respectively. A central composite design for optimization of process parameters with three independent variables included time (2, 6.5, 13.5, 20 and 25 min), the solvent concentrations (0, 20, 50, 80 and 100% of water in ethanol) and the ratio of solvent to solids (10, 14, 20, 26 and 30 solvents on the dry matter), which includes 18 test at five levels with four replicates at the central point was done. Correlation coefficients (R2) of the models for total phenolics and antioxidant activity were 0.98 and 0.93, respectively. The results of the optimization for the extraction of phenolic compounds showed that the extraction in terms of time 18.29 min, the solvent concentration of 22.15% and the ratio of solvent to solids 25.95 were the highest amount of phenolic compounds about 7.81 mg of gallic acid equivalents per gram of dry matter. Optimal conditions in terms of antioxidant activity were the ratio of solvent to solids 14.77, time 6.66 min, solvent concentration 23.37%, respectively, under these conditions, the amount of the antioxidant activity of 14.25% per gram of dry matter was obtained.

Using the ultrasound waves has been studied as a new pre-treatment for food drying in recent years. The aim of the present research is survey of the ultrasound pre-treatment effects (59 kHz, 10 min) on some physical and chemical properties of dried Poulk leaves(Stachys schtschegleevii Sosn.) using by hot dry at 40, 50 and 60oC with air velocity of 1 m/s. The results of this research showed that the lowest drying time, total phenol, antioxidant capacity and the maximum drying kinetics, reabsorption of water, and diffusion coefficient (2.42×10-10 to 4.52×10-10m2/s) was observed in the ultrasound pretreatment samples, additionally the activation energy in untreated samples was less compared to ultrasound samples. The fitted mathematical models of rate drying with the experimental data showed the model Page can satisfactory describe the rate drying curve of Poulk leaves by hot air with high correlation coefficient (R2=0.998), the minimum root mean square error (RMSE=0.02109), and chisquare (c2=0.00058).

Application of lysozyme as a natural antimicrobial or preservative agent in food and pharmaceutical industry is well known. The antimicrobial effects of lysozyme can be expanded by conjugation with carbohydrates via Maillard reaction, however this natural reaction is a time consuming process. So in this study a new method microwave heating, was applied to Accelerate the Maillard reaction. Lysozyme was mixed with dextran and heated by microwave irradiation. The glycation extent was determined by SDS-PAGE electrophoresis, cation-exchange chromatography and sugar analysis. SDS-page pattern show that with increasing heating time a high molecular weight conjugates were appeared and maximum glycosylation was occurred after 4 minutes heating. The elution profiles (chromatograms) of the lysozyme–dextran conjugates compared the natural lysozyme showed that the conjugated peak shifted towards the higher molecular weight fraction and overlapped with the non conjugated proteins, indicated that lysozyme was covalently bound to dextran. These results suggest that Maillard reaction rate can be increase using microwave heating.

In this research, the effects of fortification of chocolate samples with flaxseed at different levels of 0% (control treatment), 5%, 10%, 15% and 20% were assessed on the microbial properties, peroxide value and tocopherol content of chocolate samples during 3 months storage. Sensory attributes of chocolate samples were determined by fourteen trained panelists using 5-point Hedonic scale in 1st, 15, 30, 45 60, 75 and 90th days. It was observed that with increasing flaxseed content in chocolate samples, the mean content of gamma-tocopherols increased. The level of gamma tocopherols in control samples were 17.1 ppm, compared with 38.57 ppm in samples containing 20% flaxseed. Moreover, peroxide value showed an increasing trend with increasing flaxseed powder content. In addition, the highest peroxide value (1.875 meq/Kg) belonged to samples containing 20% flaxseed powder at the end of storage time and the lowest peroxide value (0.5 meq/Kg) was observed in control treatments in 1st day. However, all the peroxide values were in the standard range (max: 2 meq/Kg). Microbial enumeration of enterobacteriaceae, E. coli, salmonella, coagulase-positive staphylococci, yeast and molds were in the standard range during 90 days of storage. The maximum count of yeasts belonged to samples containing 20% flaxseed powder. With regard to the consumer acceptance, chocolate samples containing 5% and 10% flaxseed received higher sensory scores compared with other treatments and samples containing 20% flaxseed had the lowest sensory acceptance compared with control treatment. Consequently, the results indicated that by incorporating of flaxseed powder in chocolate, it is possible to produce functional product fortified with anti-oxidants that could have important role in the health of consumers.

One of the most important Shiga toxin-producer in dairy product is Escherichia coli O157. Milk pasteurization has not any effect on toxicity of the shigatoxin; it’s just preventing of microbial growth.Therefore, rapid and accurate detection of E.coli O157 can help to prevent food poisoning. The aim of this study was to evaluate the correlation between the presence of Shiga toxin-producing genes (stx1 and stx2) with microbial and chemical parameters in raw milk.30 samples of raw milk randomly were collected from dairy product distributors of Mashhad. Isolation of E. coli O157 H7 was done by specific culture. After DNA extraction, of 16s rRNA, stx1 and stx2 gene was screened by Polymerase Chain Reaction (PCR). The specific culture and PCR results showed that 62% and 89% of samples were contaminated by E. coli O157 H7, respectively. Also, Stx1 gene was detected in 88% of shiga toxin E.coli and Stx2 gene was not present in any of the isolates tested in this study. The correlation between the presences of Shiga toxin-producing gene (Stx1) with mesophilic bacteria enumeration, enumeration of E.coli, acidity, pH, Non-fat dry matter, fat content and domain of electro condactivity was estimated 0.174, 0.474, 0.992, 0.177, 0.724, 0.622 and 0.897, respectively. Our findings indicated that there is high correlation between chemical parameters of raw milk with the presence of shigatoxin genes in E. coli O157 H7.

Tuna fishes are among the most important commercial fishes used in Iran fish canning industry. The precooking of fish is one of the important stages of producing liquid wastes in canning factories. The liquid waste by-product obtained at this stage contains different amounts of fat removed from the fish. Fish oil includes some polyunsaturated fatty acids with long chains (PUFA), especially EPA, DHA and AA. The oil obtained from the liquid waste of cooking autoclaves of two tuna fishes, Katsuwonus pelamis and Thunnus albacares, were investigated in terms of iodin value, acidity, peroxide, oil and cooking liquid waste yield. The total yield of liquid waste showed a significant increase in Thunnus albacares (22.5%), as compared with Katsuwonus pelamis (20.4%), (p˂0.05). The oil of Thunnus albacares (1.55%) was found to be more than that of Katsuwonus pelamis (0.81%), (p˂0.05).In terms of iodin value, the oil of Katsuwonus pelamis cooking liquid waste showed higher amounts and in terms of peroxide, Thunnus albacares showed higher values (p˂0.05).The predominant fatty acids in tuna liquid waste by-product were Palmeticacid (C16: 0; 21.12%, 24.11%), oleicacid (C18: 1c 9; 15.46%, 12.35%), and docosahexaenoic acid (C22: 6 3DHA; 23%, 23.15%), for Katsuwonus pelamis and Thunnus albacares, respectively. The highest PUFA, and PUFA/SFA ratio was found in Katsuwonus pelamis and the highest SFA was found in Thunnus albacares. Finally, due to the higher unstauration degree and also, the lower peroxide in equal weights, the oil obtained from Katsuwonus pelamis is deemed to be more suitable, but in the industrial scale, because of the higher yield of the oil extracted from Thunnus albacares, this tuna fish is more preferable.

Yeasts and molds are considered as major causes of spoilage of acidic foods. Various studies have shown that green tea (Camellia sinensis) has antimicrobial properties. the study aimed to investigate the antiyeast activity of green tea extract in the plate and sterilized milk. Total phenol and flavonoid content were determined by colorimetric method. Anti-yeast activity of green tea against Saccharomyces cerevisiae, Kluyveromyces marxianusand Rhodotorula glutinis was measured using well diffusion and disk diffusion agar. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of green tea were examined by micro dilution in plate and by macro-dilution in sterilized milk in tubes. MIC of green tea extract was in range of 12.5 to 25 mg/ml in microdilution method and 6.5 to 25 mg/ml in macro dilution method. Kluyveromyces marxianus was the most resistant yeast against green tea extract. Consequently, because of the positive effect of green tea extract against the studied yeasts, it could be utilized as an anti-yeast compound in food and drug technology.

Coeliac disease is an autoimmune digestive disease that is caused by the digestion of gluten and the only treatment of this disease is a gluten free diet. In this study, at first the rice cake batter containing different percentages of basil seed gum (at four levels 0, 0.5, 1 and 1.5 %) were prepared and their rheological properties were evaluated. Batter viscosity by a brookfield rotational viscometer, physicochemical characteristics (weight, ash, moisture, volume and density) by standard methods, crumb color by image processing method, and sensory evaluation by 9-point hedonic method were evaluated. With increasing basil seed gum percentage in formulation of rice cake, the viscosity of batter increased. Rice cakes batter was a non-newtonian fluid and pseudoplastic (shear-dependent) and thixotropic (time-dependent) type. With increasing the basil seed gum from 0 t 1.5 %, rice cakes batters viscosity at shear rate of 20 s-1 ware increased from 9.82 to 49.6 Pa.s. The moisture content and volume of cakes were increased with increasing gum percentage. With increasing basil gum brightness of cakes increased due to increasing volume, in addition decreased yellowing of the samples. The L*, a* and b* indexes for sample containing 1.5 % gum were 88.35, -1.71 and 37.89, respectively. According to the sensory evaluation results, rice cake containing 1 % basil seed gum had the highest total acceptance score.

Tomato paste is one of the most common products of the tomato and most important Persian food flavors that its production has been increased in recent years. Since human health depends on the quality of processing food, it is necessary to study the quality of this product. The aim of the research is to investigate the effect of firmness and color of tomatoes and processing method on some physical, rheology and chemical properties of Tomato paste is made. For this purpose, color treatments were considered at two levels: between 15-25 and 25-35, firmness treatments were considered at two levels between 0.5-2 N and 2-4 N and processing methods were considered on two levels for hot break and cold break. Acidity, consistency, viscosity, color, Brix and pH Factors of tomato paste were measured. The results showed that the physical and mechanical properties and processing method effect on properties of tomato paste. From tomatoes with a firmer texture and hot break processing method, with more red index paste was obtained. Tomatoes that have redness index lower, consistency and viscosity of paste were higher. The results showed that the soluble solids paste that was processed by hot break is further than cold break method. Tomato paste from tomato category with more firmness and hot break processing method was more acidity. pH of less red tomato paste category and more firmness is more than less red index and more rigid categories.

Second metabolites isolated from salvia spices mostly are terpenoids and flavonoids which are bioactive compounds with high healthy effects. Extractions of these materials by solvent causes chemically unstable and lower healthy effects. Encapsulation of essential oils in a lipid carrier such as nano-emulsion is scientific way to reduce this problem. The aim of this research is encapsulation of essential oil of salvia hypoleucain nano emulsion and investigation of antimicrobial and physicochemical activities of this essential oil. Nano emulsions containing salvia hypoleuca essential oil with tween 80 and span 80 as surfactants with different HLB were produced by using high intensity ultrasound. Determination of size, distribution of particle size and physical stability of nano emulsion over time was investigated by using dynamic light scattering (DLS). Also evaluation the antimicrobial properties against gram-positive bacteria (bacillus cereus and enterococcus faecalis) and gram-negative bacteria (moraxella catarrhalis and klebsiella pneumonia) microdilution method was used. The results showed that the size and distribution of particle size were in the range of 89-141 and 0.36-0.41 and nano emulsions were stable during 60 days. Anti microbial activities of nano emulsion against all bacteria were better than free essential oils.