فهرست مطالب mehdi kashaninejad

Among the various hot air drying methods, fluidized bed drying has significant advantages such as high heat and mass transfer, uniform moisture reduction of products with short time and high drying rate and uniform process at entire surface of the product due to efficient mixing with the drying air and high efficiency of process. In recent years, usage of infrared drying to dry food products has increased over conventional drying methods due to higher product quality, uniform heat distribution, high energy efficiency, high heat transfer rate and less processing time, facilitating the control of raw material temperature, reduced necessity for air flow across and the high ability to control process parameters in infrared heating. In this study, kinetics of carrot cubes drying by infrared-fluidized bed dryer were investigated.

Fresh carrot were washed with tap water and peeled manually then diced by dicer. To drying carrot cubes by combined infrared- fluidized bed method a laboratory scale dryer was designed and performed. In this study, drying of carrot cubes (0.5 and 1 cm3) was performed in factorial design experiments using air temperatures of 50, 60 and 70 °C and three levels of infrared power (200, 400 and 600 W) in three replications. To describing the infrared-fluidized bed drying behavior of carrot cubes, five mathematical models (Page, Modified Page, Henderson & Pabis, Midilli and Logarithmic) were evaluated.

The results demonstrated that the change in inlet air temperature, size of carrot cubes and infrared power had a significant effect (P <0.05) on water withdrawal from the sample and drying time decreased with increasing air temperature and infrared power and decreasing carrot cubes size. Therefore, the energy consumption was also reduced considerably, decreasing from 12.63 Kwh/kg in bed fluidized method (without infrared power) to 2.28 Kwh/kg using infrared -fluidized bed drying. The Page model was identified as the suitable model to describe the drying kinetics of carrot cubes by infrared-fluidized bed dryer that showed a good agreement with experimental data.

The statistical analysis of variance showed that air temperature, sample size and infrared power had a significant effect on water withdrawal rate of samples and therefore drying time. According to the results, using infrared-fluidized bed drying as a combined method in comparison with conventional hot air drying methods can reduce drying time and energy consumption and costs considerably.

Millet is one of the cereals that used in the preparation of gluten-free products for celiac patients. Physical modification methods such as heat-moisture treatments and microwave can be used to improve the performance of gluten-free flours in the baking industry. Millet seeds have limited shelf life in normal storage condition due to its relatively high fat content and high activity of lipase enzymes. In this study Heat-moisture treatments at different levels of moisture (11,15 and 20%) and two different temperatures (90 and 110°C) for 3 hours in oven and microwave treatment at different levels of moisture (11,15 and 20%) were used at different times (30,60 and 90S) with a constant power of 900 W. Then, in order to ensure the effect of the above treatments, the amount of free fatty acids of the treated flours was measured every 10 days as well as the level of lipase activity on the first day and after 30 days. In the heat-moisture treatment, the rate of inactivation of the lipase enzyme increased with simultaneous increase of moisture and temperature of the oven as well as in the microwave treatment with simultaneous increase of moisture and microwave time and the amount of free fatty acid flour during 30 days of storage was reduced. The highest rate of inactivation of lipase enzyme and the least change in the free fatty acid content of flour in heat-moisture and microwave treatments were observed in treatment with 20% moisture content and 110°C, and treatment with 20% moisture and 90S.

In food industry, the use of quality monitoring and evaluating systems which increase the production efficiency and desirability of product is increasing. Fuzzy logic has provided an appropriate tool in the design of the decision maker systems based on human experience. In this study, a fuzzy system was designed for sensory evaluation of apple slices during drying using infrared radiation. For this purpose, the slices of apple were prepared in three thicknesses of 5 (Thin), 9 (Moderate) and 13 mm (Thick). Intermittent radiation operation was performed at three constant temperatures of 70 (Low), 75 (Moderate) and 80 °C (High) to achieve a moisture level of 15 (Low), 20 (Moderate) and 25 % kg/kg, wb (High). Evaluating the sensory attributes including color, aroma, flavor, texture and overall acceptability was performed by ten trained panelists using linguistic and hedonic method. Similarity analysis between sensory properties in terms of importance and statistical analysis for considering the impact of process conditions on the desirability were also performed. Finally, the fuzzy model has been set. The results showed that, color and texture are of the same importance with Pearson correlation coefficient (PCC) equal to 0.981 in the sensory evaluation. Sensory qualities of apple slices were better in thin slices, low temperature and moderate humidity. Fuzzy model with mean absolute percentage error (MAPE) equal to 14.54 %, had a good prediction about average evaluated scores.

Olive leaf is one of the richest sources of phenolic compounds with antioxidant properties. Use of these compounds as food and pharmaceutical ingredients face challenges like protecting them during storage and food processing. In this study, bioactive compounds of olive leaf aqueous extract were encapsulated into a sucrose matrix using co-crystallization process. The co-crystallized powders were characterized in terms of their morphology, thermal behavior, chemical structure and also polyphenols and antioxidant activity retention rate, under various storage conditions such as light, moisture and temperature for period of 4 months. DSC thermograms for all samples, indicated the peaks around 190 C typical of sucrose melting behavior. FT-IR analysis for all samples showed typical bands of sucrose molecule. At the end of storage time, co-crystallized products containing 10% extract which were stored at dark condition, showed the highest preservation rate of polyphenols around 92% and antioxidant activity around 77.35%. A significant decrease (P˂0.05) was observed in preservation rate of polyphenols and antioxidant activity for powders stored in artificial light and RH=75% conditions compared to storage at dark and 4 °C conditions.

According to FAO statistics, Iran with production about 1023130 million tons date in 2010, is the third largest producer of date fruits in the world after Egypt and Saudi Arabia. However, 30 percent of date product is discarded. Date paste is a by-product that can reduce waste. Moisture and water activity (aw) reduction of date and its paste can increase production efficiency. This research was made experimentally to determine thin layer drying of date paste in different drying conditions and effect of temperature and thickness on time and rate of drying in date paste and finding the best experimental model.
Date of Mozafati variety, first peeled, destoned and then converted to paste. The prepared date paste was kept in freezer -18 OC and before each test equilibrated with its environment. Thin layer drying characteristics of date paste were determined in hot air dryer. Air temperature was controlled with sensors connected into thermocouple. Weight changes with ±0.1 accuracy recorded with 10 seconds intervals. Date pasts were dried in factorial design experiments using three air temperature levels (70, 80 and 90 oC) and two levels of thickness (3 and 5 mm) with constant hot air velocity (1.5 m / s) in three replications. Eight mathematical models (Lewis, Henderson and Pabis, Page, Modified Page, midilli, Khazaei, Diffusion and Exponential) for describing the hot air drying behavior of date paste were investigated.
temperature of dryer environment is the main and determining factor for drying rate according the findings. By increasing temperature in each thickness, moisture ratio (MR) decrease instantly, so the drying rate increases and drying time decreases. Page and Khazaei models were found to be the most suitable models for describing the drying behavior of the date paste. The drying air temperature had the greatest effect and thickness had the smallest effect on the drying kinetics of date paste. Effective diffusivity of water varied from 1.5517 × 10 -9 to 2.1806 × 10 -10 m2 / s. The activation energy during the studied temperature range calculated 13.166 KJ / mol. The temperature dependence of the diffusivity coefficients was described satisfactorily by a simple Arrhenius-type relationship.
Temperature and thickness are two important factors in date paste drying. The effect of temperature is more significant than thickness. Drying temperature increment had highly impact on the equilibrium moisture content (Me) and drying time in the range of our test.

Cake, because of various tastes and ease of use, is the most important baking product after bread. Considering the mechanism of celiac disease, which develops because person's body cant digest the gluten proteins, producing gluten free cake is increasing across the world. The goal of this research is to analysis using of sweet almond protein concentrate (SAPC) in four levels ( 0, 5, 10, 15) and xanthan gum in three levels ( 0, 0.2, 0.4) (rice flour basis) on physical characteristics of dough and chemical and textural properties of free-gluten cake . Results show that by increasing the level of SAPC, protein, moisture, and ash of cake increase. By adding xanthan gum and SAPC, Special weight and Consistency of dough increase too. According to these results, the sample containing 0.4% xanthan and 15% SAPC has the most hardness and sample with 0.4 % xanthan and without SAPC has less hardness. Besides, xanthan decreases gumminess and increases springiness and cohesiveness. SAPC increases gumminess and decreases springiness and cohesiveness. Finally level of 2.0% for xanthan and 5% for SAPC due to suitable quality properties were accepted.

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.

The purpose of this research was to study the effect of thin layer 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 drying oil, olive oil, hot water without pretreatment (control)) on cabinet drying process of grape and color of obtained raisin. Six mathematical models were fitted on drying data and the best one was selected according to coefficient of determination (R2), Root Mean Square Error (RMSE) and coefficient of relative average deviation (P). The results showed that temperature, air velocity and pretreatment have significant effects on drying rate and color of raisin. Among these models, two term and page models showed more ability to evaluating and describing drying behavior of grape. Diffusion coefficient values were between 4/6274×10-10 to 8/6541×10-10 m/s2 and activation energy obtained 13470/83 J/mol. The best values of lightness and redness were related to dried raisin at 60 oC and the maximum value of yellowness was related to dried raisin at 70o C. Drying air velocity just significantly affected the redness. Increasing drying air velocity decreased the redness. It was also found out that potassium carbonate and Paksan drying oil pretreatment caused the best raisin color.

The basis of the Ohmic Heating process is the transmission of alternating electric current through multi-phase solutions that is followed by heat generation due to particle resistance to the transmitted electric current. Throughout the present study، simultaneous transfer of heat and electricity was modeled in a two-phase system of solid-liquid food to investigate the critical factors affecting the process. A three-dimensional simulation was employed in the modeling to investigate the effect of particle distribution، salt diffusion as well as electrical conductivity. The results revealed that there existed a good agreement between the results of the modeling with the experimental results. It was also revealed that with increase in the concentration of salts and electrical conductivity، heating rate increased. In total، it can be concluded that heat and electricity diffusion throughout the product is faster than that in conventional heating methods and proceed similarly and almost with equal speed in both liquid and solid phases.

Raisin is a principal traditional export product of Iran and has occupied a special position in the foreign trade of the country. During storage period, the product turns sticky and hard due to exudates syrup and moisture loss. To overcome this problem the application of edible coating suggests being of proper assistance. Edible coating may enhance the boundary layer resistance resulting enhanced shelf life of product. In this research the method of Accelerated Shelf Life Testing (ASLT) used for evaluation of storage and sensory properties (texture, colorو taste and overall acceptability) of raisin. Raisin was treated with coating materials based on lipid (glyceryl monoestearate and carnauba wax) with 150 ppm essential oil of thyme (thymus vulgaris) and stored at 20, 35 and 50oC for 12 weeks. During this period of storage sensory properties were evaluated and estimate the modeling shelf life of raisin. Results showed that coating, affect on texture and color significantly and caused increasing shelf life of raisin. Temperature and storage time also showed significant effects on total sensory attributes. Maximum shelf life (394 days) determined at 20 oC for carnauba wax coating with essential oil of thyme based on overall acceptability and linear regression and second order function had best fit with R2≥0. 94 for all of treatments.

The aim of this research was to survey of using soy protein isolates and tragacanth gum as egg substitutes in mayonnaise formulation. The mayonnaise prepared with difierent compositions of soy protein isolate، egg، and tragacanth by applying the optimal mixture design method and effect of this substitution on its stability، heat stability، viscosity، texture، physicochemical and sensory characteristics of mayonnaise were considered. According to the results، with an increase of replacement tragacanth and soy protein isolates، stability in samples 4،5، 6 and 7 increased. Generally،all treatments showed stability higher than 98%. Viscosity all treatments except treatment 2 and 9 (respectively،23. 92 and 32. 02 pa. s) Compared to the control sample increased and in total there are statistically significant differences between all samples. Generally، samples containing soy protein isolates and tragacanth، had acceptable quality in terms of investigated properties. The highest rating from Sensory properties was awarded to treatment 5 (55/55% replacement with soy protein isolates with tragacanth). So، with the right concentration of tragacanth and soy protein isolates، egg mayonnaise can be greatly reduced.