Azam Ayoubi; Nasser Sedaghat; Mahdi Kashani-Nejad; Mohebbat Mohebbi; Mehdi Nasiri mahalati
Abstract
The purpose of this research was study effect of drying conditions (temperature at three levels of 60,70, and 80 oC, air velocity at two levels of 1/5 and 2/5 m/s, and four pretreatments including potassium carbonate and paksan oil, olive oil, hot water and no pretreatment (control)) on drying grape ...
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The purpose of this research was study effect of drying conditions (temperature at three levels of 60,70, and 80 oC, air velocity at two levels of 1/5 and 2/5 m/s, and four pretreatments including potassium carbonate and paksan oil, olive oil, hot water and no pretreatment (control)) on drying grape process and quality of raisin including rehydration, shrinkage, hardness and browning index. The results showed that temperature, air velocity and pretreatment have significant effects on drying rate and quality of raisin. Drying rate increased with increasing temperature and air velocity and with application of preatreatment. The best values of hardness (0.73 N), shrinkage (81/04%) and the least value of browning index (0/157) were related to dried raisin at 60 oC and most value of rehydration (1/266) was related to dried raisin at 70 oC. Air velocity just significantly affected on browning index. Increasing air velocity decreased browning index. Also between used preatreatments , potassium carbonate and paksan oil caused best physicochemical results.
Azam Ayoubi; Nasser Sedaghat; Mahdi Kashani-Nejad; Mohebbat Mohebbi; Mehdi Nasiri mahalati
Abstract
Introduction: Raisin is a principal traditional export product of Iran and has a special position in the foreign trade of the country.During storage, the product turns sticky and hard due to exudates syrup and moisture loss. To solve this problem, the application of edible coating would be an appropriatesolution. ...
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Introduction: Raisin is a principal traditional export product of Iran and has a special position in the foreign trade of the country.During storage, the product turns sticky and hard due to exudates syrup and moisture loss. To solve this problem, the application of edible coating would be an appropriatesolution. Edible coating may enhance the boundary layer resistance resulting to the enhanced shelf life of the product. Edible coatings are thin layers of edible materials applied to the product surface in addition to or as a replacement for natural protective waxy coatings and provide a barrier to oxygen, water and solute movement. They are also applied in foods to minimize the migration of components within the food systems or between the foods and their surrounding environment. They are used directly on the food surface by spraying, dipping or brushing to create a modified atmosphere. There are different kinds of films which are used such as polysaccharide, protein, lipid and composites. Lipid based coatings are primarily used for their hydrophobic properties which make them good barriers to water loss. In addition to preventing water loss, lipid coatings have been used to improve appearance by generating a shiny coverin fruits and vegetables, and to decrease respiration, thereby extending shelf life. The moisture barrier properties of hydrophilic coatings can sometimes be improved by addition of lipid materials The purpose of this research was to study the effect of lipid based edible coating (glycerylmonoestearate and carnauba wax) on physicochemical and microbial properties of raisin. Material and methods: Raisin samples (cvAskari)were dried usingsoda oil method and treated with coating materials based on lipid with essential oil of thyme (thymus vulgaris).Glycerylmonoestearate, carnauba wax and tween 80 were purchased from Sciencelab, Sigma-Aldrich and Merck Co. respectively. Raisinswerecoated with the following coating solutions: -Aqueous solution of tween 80 (0.5% w/w) -Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w) -Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme -Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w) -Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme Control sample was treated with aqueous solution of tween 80 (0.5% w/w).Distilled water was used for preparing all of coating solutions. Coating solutions were stirred and heated to 75oC (melting point of coating materials) for 30 min on a hotplate with a magnetic stirred to obtain uniform solutions. Dipping technique was used for coating of raisins. The coated raisins were placed on a basket to drip off residual coating solution and were dried in 25oC. The raisin smples were packaged in a 3 laminatedlayer bags (PE/PA/PE) with thickness of 80µ by Henkelman packaging machine and were stored at20, 35 and 50oC for 12 weeks. During the storage period, moisture content, water activity, hardness, color parameters (L*(lightness), a*(redness) and b*(yellowness)), percent of pestilence and microbial properties (total count, mold and yeast) were evaluated. Hardness of raisins was determined in apuncture test using a QTS texture analyzer (CNS Farnelll, Essex, UK) equipped with a needle probe (stainless steel cylinder of 2 mm of diameter with a conical needle bit) and a test speed of 60 mm. min−1 during the test. Hardness was defined as maximum force to puncture raisin from the top to a 2mm depth (Rolleet al. 2011).For colormeasurement, raisins were placed in to a black wooden box (interior size of 0.5 (width) × 0.5 (length) × 0.8 (height) m3 and were illuminated using 3 fluorescent tube lights (10W, 6500K; 40cm in length). A digital camera (Canoon EOS 1000D, Powershot, Taiwan) was located vertically at a distance of 20cm from the raisin surface. The images were preprocessed by Adobe Photoshop software, version 5.5. The Color properties were analyzed using ImageJ software, version 1.44o. The experiments were factorial with a completely randomized design. The coating material, temperature and storage time were the independent variables. Analysis of variance (ANOVA) was conducted for data using MSTAT-C software, version 1.42 (Michigan State University). Differences among the mean values were also determined using Duncan’s Multiple Range test. A significant level was defined as a probability of 0.05. The experiments were carried out on 4, 8 and 12 weeks after storage with three replications. Results and discussion: Results showed that coating, temperature and storage time would have considerable effect on the physicochemical and microbial properties of raisin. Coating caused decreasein moisture loss, hardness, lightness and redness. Increasing temperature and storage time increasedmoisture loss and hardness. Minimum hardness values were measured for 20 oC and 4 weeks storage and maximum hardness values were related to 50 oC and 12 weeks storage. Also it seems that increasing temperature and storage time influences thehardness by increasing moisture loss. Increasing temperature and storage time significantly decreased L* (p≤0.01). Increased enzymatic browning in raisins with increasing temperature was accompanied by an increase in a* value, and a decrease in b* value and caused to presenting dull colors. Total count, mold and yeast of coated samples decreased during storage period. Carnauba wax was more effective than glycerylmonoestearate on stability of raisin. Essential oil of thyme also caused improving color and microbial properties. Least values of redness (-2), total count (2.06 log cfu/g) and mold and yeast (1.32 log cfu/g) were related to carnauba wax coating with essential oil of thyme.
Parviz Bashiri; Mohammad Hossein Hadad Khodaparast; Nasser Sedaghat; Farideh Tabatabaei Yazdi; Mehdi Nasiri mahalati
Abstract
In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0(control), ...
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In this research effectiveness of immersing three types of contaminated pistachios fresh with hull (exocarp or epicarp), dried in shell and dried with hull from Ohady cultivar in ozonated water 0 ppm (control), 4 and 8 ppm ozone concentrations in aqueous solution for range of exposure times 0(control), 2, 4, 6, 8, 10 and12 hours, to decrease of aflatoxin (B1, B2, G1, G2 and total) were investigated. Water temperature and pH were 10°C and 5.5± 0.3 respectively. For all samples, interaction between, ozone concentration and exposure times or pistachio type, were investigated. Aflatoxin (AF) B1 content was more and was reduced easily. Results showed that differences between the control samples (zero hour and/or 0ppm ozone) and treated pistachios for total aflatoxins and aflatoxin B1 were significant(P < 0.05). For control samples, the means of aflatoxin reduction for B1, B2, G1, G2 and total were, 5.6, 9.7, 14, 6, 15 and 6.4 percentage, respectively and for ozonated pistachios were 32.7, 8.55, 30.6, 34 and 35 percentage, by 4ppm ozone concentration. The results for 8ppm ozone concentration were, 47.9, 12.5, 45.8, 43.9 and 44.4percentage, respectively. The results indicated that the effect of ozonated water on reduction of aflatoxin content from the samples significantly depends on the level of ozone concentration and exposure times. The results also demonstrated that ozone susceptibility of aflatoxins to destruction were B1 & G1 >G2 & B2 respectively.
Adeleh Soleimani; Mohammad Javad Varidi; Alireza Sadeghi Mahoonak; Mehdi Nasiri mahalati
Abstract
This study was carried out to evaluate the chemical compoition of Alosa Caspia and results compared with Clupeonella engrauliformis which is a common fish catch among Clupeonella and Clupeidae spp in Caspian sea . Results showed that the amount of fat, protein, ash and dry matter in Alosa was higher ...
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This study was carried out to evaluate the chemical compoition of Alosa Caspia and results compared with Clupeonella engrauliformis which is a common fish catch among Clupeonella and Clupeidae spp in Caspian sea . Results showed that the amount of fat, protein, ash and dry matter in Alosa was higher than Clupeonella. The fatty acid composition showed that the EPA was very high in Alosa that show this fish is rich source of omega-3 fatty acid. Then the effect of salting method on moisture and salt content Alosa Caspia were evaluated. The salting methods including traditional (common in north reigon), brining with two salt concentration (saturated and 20% w/w brine) followed by two drying methods (sun and oven drying at 30°) were used. The texture changes during salting showed that salt absorption and water loss was different in different salting method and was higher in traditional salting method. These samples had the lowest moisture at the end of salting, but showed the highest moisture at the end of drying.
Roya Rezaee; Fakhri Shahidi; Mohammad Elahi; Mohebbat Mohebbi; Mehdi Nasiri mahalati
Abstract
In this research, the production of plum pastille-like with starch and gelatin was studied. Thirteen formulation of plum pastille-like were prepared according to a second-order composite rotatable design (with five central points). Response surface methodology (RSM) was used to optimize product formulation ...
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In this research, the production of plum pastille-like with starch and gelatin was studied. Thirteen formulation of plum pastille-like were prepared according to a second-order composite rotatable design (with five central points). Response surface methodology (RSM) was used to optimize product formulation with: gelatin concentration ranging from 3.85 to 6.925 % (w/w), and starch concentration ranging from 0 to 3.85 % (w/w) as independent variables. The dependent variables were texture objective evaluation and total acceptance obtained from sensory analysis. The texture and flavor attributes of the samples were identified and evaluated by a trained descriptive panel. The thickeners strongly affected texture and flavor attributes of the samples. The resulting polynomial equation (R2=0.9325) revealed that a formulation with 5.38% gelatin and 3.85% starch had a maximum total acceptance.
Elham Zaerzadeh; Seyed Ali Mortazavi; Mahmoud Reza Jafari; Sima Afsharnejad; Farideh Tabatabaei Yazdi; Mehdi Nasiri mahalati
Abstract
The objective of this study was evaluating the effectiveness of encapsulated nisin in liposoms in contrast to free nisin in control of Listeria monocytogenes ATCC 19117 in Feta cheese during its ripening. The size of the nano-encapsules with nisin was around 103-150 nm and of the nano-encapsules without ...
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The objective of this study was evaluating the effectiveness of encapsulated nisin in liposoms in contrast to free nisin in control of Listeria monocytogenes ATCC 19117 in Feta cheese during its ripening. The size of the nano-encapsules with nisin was around 103-150 nm and of the nano-encapsules without nisin was of approximately 101-143 nm. Addition of 500IU/g nisin to cheese resulted into 0.57, 4 and 3.7 log reduction in viable cells, respectively in free nisin, nano-encapsulated nisin (formulation 1) and nano-encapsulated nisin (formulation 2) at the end of four weeks ripening. In addition, changes in pH during this period of time was also affected by the form of addition of nisin, it was significantly different from liposomal nisin formulations(p
Bahareh Emadzadeh; Mohammad Javad Varidi; Mehdi Nasiri mahalati
Abstract
Sheep meat is one of the most important sources of red meat in middle-east countries and therefore having knowledge of its quality is necessary. The physicho-chemical characteristics of sheep meat were studied during 7 days of ageing period. Samples were taken from the top round section including Biceps ...
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Sheep meat is one of the most important sources of red meat in middle-east countries and therefore having knowledge of its quality is necessary. The physicho-chemical characteristics of sheep meat were studied during 7 days of ageing period. Samples were taken from the top round section including Biceps femoris and Semimembranosus muscles. Meat pH fell significantly during the first 24 h postmortem, reaching the mean value of 5.67±0.06. No significant changes (P
Bahareh Emadzadeh; Mohammad Javad Varidi; Mehdi Nasiri mahalati
Abstract
Carcass yield is important economical parameters for producers and contributors of meat science. In the present study, carcass yield and also the weight losses resulted post mortem until consumption were investigated. The mean values of cold carcass and hot carcass weight were 15.63 and 15.33, the mean ...
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Carcass yield is important economical parameters for producers and contributors of meat science. In the present study, carcass yield and also the weight losses resulted post mortem until consumption were investigated. The mean values of cold carcass and hot carcass weight were 15.63 and 15.33, the mean value of cooling loss was 1.87% and average value of hot and cold efficiency were 41.44% and 40.67%, respectively. The correlation between the weight of sheep and cold carcass weight was modeled using a power function with a high correlation coefficient. The mean value of drip loss and cooking loss were 2.10% and 24.51%, respectively. All parameters were evaluated for both sexes individually indicating that there was no statistically significant difference between sexes.
Keywords: Sheep meat; ageing; Hot and cold carcass yield; Cooling loss; drip loss; cooking loss
Masoud Yavarmanesh; Seyed Ali Mortazavi; Mehdi Nasiri mahalati; Javad Barooei
Abstract
Food borne viral infections are recognized increasingly as human illneses. Hepatitis A virus (HAV) is an important pathogen which has been responsible for water and many food – borne outbreeks especially milk . In this study for approaching to best diagnosis method of HAV in milk by ELISA technique, ...
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Food borne viral infections are recognized increasingly as human illneses. Hepatitis A virus (HAV) is an important pathogen which has been responsible for water and many food – borne outbreeks especially milk . In this study for approaching to best diagnosis method of HAV in milk by ELISA technique, various dilutions of HAV antigen (1 ml/L, 10-3 ml/L, 10-6 ml/L, 10-9 ml/L) were added to UHT milk . Various treatments for virus(antigen) isolation, showed that milk with acidic coagulation, following filtration with paper and membrane filters, had the most optical density. It`s indicated that this treatment resulted the best diagnosis . Also it has been revealed that this method has not any sensitivity for quantitative determination of HAV(antigen) in milk.
Key words: diagnosis, Hepatitis A virus(HAV), Milk, ELISA
