Azam Ayoubi; Mahda Porabolghasem
Abstract
Introduction: Increased intake of calorie and decreasing physical activity might increase the risks for cancer, obesity, cardiovascular diseases, diabetes mellitus and hypertension. Using natural sweeteners instead of sugar in food formulations can be a good method to reduce the calorie intake. World ...
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Introduction: Increased intake of calorie and decreasing physical activity might increase the risks for cancer, obesity, cardiovascular diseases, diabetes mellitus and hypertension. Using natural sweeteners instead of sugar in food formulations can be a good method to reduce the calorie intake. World Health Organization recommends limiting added sugar intake to <10% of total energy. Many sugar substitutes were used in food products such as glucose syrup, molasses, fructose syrup, invert syrup and malt extract. Utilization of fruits in food preparation while requiring sweet taste is a wise strategy to reduce the added sugar intake. Dates are ideal fruits to substitute added sugar in foods, and they play an important role in daily nutrition of many people in the arid regions. Date fruits are rich in dietary fiber, phenolic compounds, minerals, vitamins, antioxidant and antimutagenic compounds. Date syrup that produces from date is one of the suitable replacements that can be used for substituting sugar. Date syrup is a high energy food rich in carbohydrate, a good source of minerals; but it is also contains a very complex mixture amino and organic acids, polyphenols and carotenoids. Date syrup contains fructose, glucose and small amount of sucrose. Low quality date cultivation occupies about 60% of the total plantation. These dates are poor in size and taste, unsuitable for consumption. The presence of high sugar content in these low quality varieties makes them suitable for producing date syrup. The purpose of this research was study the effects of substituting sugar with date syrup on physicochemical and sensory properties of cupcake.
Materials and methods: Date syrup purchase from Dambaz Company and wheat flour purchase from Tavakkol factory of Kerman. Other materials purchased from local market of Kerman. In this research four different level of date syrup (25, 50, 75 and 100%) were used in cake formulations as a sugar substitution and the effects of dates syrup on the physicochemical (including weight loss, pH, porosity, density, moisture, hardness of texture and color of crust and crump) and sensory (texture, crust color, taste and total acceptance) properties of cupcake were studied. The weight loss calculated by measuring difference of weight before and after baking. pH was measured by a digital pH meter. cake moisture content was determined by drying samples at 130±2°C in a hot air oven. The volumes of the cake samples were measured by the seed displacement method and then density was calculated by dividing the volume by the weight. For evaluation of porosity used Image j method. Hardness of the cake samples were measured with Instron testing machine. Color measurements were done using a Hunterlab Colorimeter. Analysis of variance (ANOVA) was conducted for data using MSTAT-C software. 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.
Results & Discussion: Data analysis showed that the date syrup, significantly affected the physiochemical and sensory properties of the cake. It was discovered that by increasing the percentage of date syrup in cake formulation, weight loss decreased and moisture increased. Sugars make hydrogen bonds with water molecules due to their hydroxyl groups, because of the molecular structure of the sugars like sucrose, fructose and glucose, it seems that increasing functional groups in date syrup sugars compared with sucrose, resulted in the formation of more hydrogen bonds, which caused the reduction in the mobility of free water and therefore make an increase in moisture of cake. According to the results, pH and porosity of the cake decreased as the date syrup level increased. The results showed that increasing date syrup level caused an increase in density. By decreasing the volume of cake density increased. The volume probability decreased because of affecting reduced sugars and changing viscosity and density of the cake batter. Based on the results, hardness increased significantly with increasing replacement of sugar with date syrup. The possible reason for this result was due to decreasing volume and porosity of cake with increasing date syrup content. The color of the cake is due to the Maillard and caramelization reactions during baking. A key element in Maillard reaction is reducing sugar which is abundant in date syrup and able to enhance the brown color. The results showed that the crust and crump lightness (L) decreased significantly with increasing the levels of date syrup. The crust and crump yellowness (b) were significantly less than control. With reducing sucrose level, the redness of the crust and crump increased significantly. According to sensory evaluation results, scores of crust color, texture and total acceptance of the cake remained unchanged when up To 50% date syrup was used. However, further addition of date syrup significantly reduced these scores. The results showed that the cake formulation with 100% date syrup date obtained the lowest score by panelists in terms of taste. Least value of weight loss (19/2%), porosity (19/5%) and most value of density (0/5 g/cm3), darkness of crust (32/47) and crump of cake (35/64) were related to substitution level of 100%. Present study demonstrated that the date syrup could replace up to 50% of the sugar without affecting the quality of cupcakes.
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.
Azam Ayoubi; Mohammad Bagher Habibi Najafi; Mahdi Karimi
Abstract
In this study, physicochemical and organoleptical properties of muffin cake prepared by substitution of egg white with different levels of whey protein concentrate (WPC) and different levels of guar and xanthan gums in the furmolation were evaluated.WPC at three levels ;25 , 50 and 75 % , guar gum at ...
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In this study, physicochemical and organoleptical properties of muffin cake prepared by substitution of egg white with different levels of whey protein concentrate (WPC) and different levels of guar and xanthan gums in the furmolation were evaluated.WPC at three levels ;25 , 50 and 75 % , guar gum at two levels ; 0.1 and 0.3 % , and xanthan gum at two levels ; 0.1 and 0.15 % , were considered as variable treatments . Data analysis showed that addition of WPC, significantly affected the physicohemical and sensory properties of the samples. Moreover guar and xathan gum affected all the physicochemical and sensory properties except for the after one and two days of storage, crust colour and taste. The results of this research showed that although WPC alone was not an appropriet substitution for egg white, the application of WPC at levels of 25 and 50% along with guar (0.3%) or xanthan gum (0.15%) could be an appropriate substitution for egg white while maintaining sensory properties and improving almost all of the physicohemical characteristices of muffin cakes.
Key words: muffin cake; whey protein concentrate; guar gum; xanthan gum; physicochemical properties; organoleptical properties.
