Iranian Journal of Biosystems Engineering
Year:2008 | Volume:39 | Issue:1|Papers Count:20

Tensile mechanical properties of brown rice grain were determined for two rice varieties of Hashemi and Khazar at three moisture content levels of 10.2, 12.2 and 13.25% (w. b.), and four drying temperature levels of 35,45, 55 and 64°C. The mechanical testes were conducted in the diametral compression test method, because of the experimental difficulties involved in the uniaxial tension tests. In this method a core specimen of brown rice is pressed in a lying posision between two flat plates. Tensile strength, tensile failure strain and tensile modulus of elasticity were determined for various treatments. Statistical analysis of the results showed that variety, moisture content and drying temperature significantly affected the properties examined. However, variety had no significant influnce on tensile failure strain. In general, all the tensile mechanical properties increased as moisture content and/or temperature of kernel decreased. Moisture content had the greatest effect on different mechanical properties of rice. Analysis of varience .of data indicated that variety exerted a significant effect (at %5 level) on tensile strength. Tensile strength of Hashemi variety was greater than that of Khazar. This puts emphasis on stress cracking susceptibility due to variety. At the different experimental conditions of the study, Hashemi and Khazar rice tensile strengths ranged from 3.97 to 10.05 and 3.19 to 8.10 MPa, respectively, emphaizing the stress cracking susceptibility of these varieties.

Energy method of evaluation is widely employed in analyzing problems associated with sustainable agriculture. In this study, energy ratio (ER) of dryland wheat for three regions of Eghlid township was quantified. The total croppingarea of Eghlid is nearly 8282 hectares comprised of: Khosrowshirin (5000 ha), Sedeh (1682 ha) and Dezhkord (1600 ha). The corresponding values of wheat yield in these subareas are 1, 1.02 and 0.9 ton/ha, respectively. In this township, dryland cropping is performed via two methods: mechanized (using moldboard plow and then deep seed drilling) vs semi-mechanized (manual seed broadcasting, or using a "seed broadcaster and then applying the moldboard plow). In this study, the' equivalent energy inputs and outputs for either one of the methods was evaluatted or then the corresponding energy ratio determined. Inputs were: fertilizer, seed, pesticide, fuel, equipment, labor, while outputs being grain yield and straw. Grain energy ratio for Khosrowshirin, Sedeh" and Dezhkord were obtained as 1.068, 1.19 and 0.91, respectively, while the corresponding values related to both grain and straw (total biological output) were 1.61, 1.80 and 1.36; respectively. Consequently, for the township, the corresponding mean values related to grain vs both grain and straw were calculated as 1.06 and 1.60, respectively. Input energy of dryland wheat was found to be 12.49 GJ/ha and total output energy (grain and straw) was 20.056 GJ/ha leading to the net energy gain (NEG) of 7.54 GJ/ha. Mean values of fertilizer, fuel seed, equipment, pesticide, and labor were becomes evident 57.5%, 28.4%, 12.1%, 1.25%, 0.38%, and 0.02%, " respectively. It becomes evident that the input items fertilizer and fuel have dedicated to themselves the highest values of energy consumption the magnitudes of which should be optimized for implementation of an efficient management. Improportionate consumption of these inputs not only increases the production costs involved but also adds to the pollution of the atmosphere, soil and water resources as well.

Wheat straw, as an animal feed source, is of a low nutritional value, which can be enriched through a process of urea treatment. This process is the rewetting of the straw to the point of increasing its moisture content up to 30-50 percent using urea solution. The conventional method of treatment is a laborious, tedious and time consuming task. To facilitate this process some of these operations can be eliminated while employing mechanized treatment. In this method urea treatment can be accomplished simultaneously with straw being collected and compacted, through nozzles installed on a baler. For the purpose, the moisture fluctuating characteristics of rewetting straw were needed. Experiments were conducted in a completely. randomized factorial design of 3 replications through urea solution sprinkling of straw by two kinds of nozzles (conical and t-jet) on a certain mass of straw (100 g), at four levels of compacted densities (5, 50, 85 and 120 kg.m-3) and three levels of flow rate (400, 600 and 800 g.min-1).The amounts of pre-drainage water content (Ma), final water content (Me), saturation moisture content (Ms) and drainage quantity (Md) for the straw were assessed at different flow rates and for different straw densities. The results of analysis of variance indicated that, density, flow rate, and nozzle type significantly affected Ma, Me, Ms and Md (P£0.01). Through an increase of density, the amounts of Me and Ms decreased while they increased through an increase of flow rate. A combination of 5 kg.m-3 and 800 g.min-1 with t-jet nozzle, which led to the highest water holding content along with the lowest drainage, were selected as the most proper options for mechanized urea treatment of wheat straw.  

Pomegranate (Punica granatum. L) is one of the popular edible fruits believed to be native Iran. It is presently widely grown in many other tropical and subtropical countries. In this study, anthocyanin profiles for four cultivars .of Iranian pomegranate (Punica granatum. L) juice were determined and quantified through high-performance liquid chromatography coupled to UV-Vis detector (HPLC-UV) using individual calculations from the peak areas based on standard curves of each composition. Anthocyanin contents were highly variable among cultivars (Sweet Alak, Saveh Black leather, Tabas bone leather and Saveh sweet white leather). Results demonstrated that despite morphologkal similarities among cultivars, there are significant differences observed in chemical comounds as well as anthocyanine content among them. The highest level of Total Tannin was observed in Sweet Alak cultivar (3.20 mg/l) and the cultivar Tabas bone contained the highest contents of Total Anthocyanin (7758.80 mg/l), Total Sugar (13.86 g/100g), Total Acidity (1.20 g/100g). So one can assign different cultivars to different uses. HPLC fingerprint of anthocyanins content for each cultivar was elaborated and stored in a database.

Alpha amylase is an important enzyme found in barley grain which is activated during grain malting stages. This enzyme, because of its 'Stability against heat and its specific ability in liquefying starch and transformation of starch into its simple sugars is wary important in industry & medicine. Different methods including addition of growth hormones and/or genetic alteration have been reported to increase the activity of this enzyme during seed germination stages. In this study, the effect of ultrasound as an emerging technology was investigated on the activity of this post germination of the grain produced enzyme. All experiments were conducted at 20 KHz on the ultrasonic generator by considering the three effective factors of temperature (30, 50 and 70°C), ultrasonic intensities of 20, 60 and 100% setting from nominal power of the device (460W and °C ) in different time intervals (5, 10 and 15 min). Fuwa method assay based on the decreased staining value of blue starch-iodine complexes was employed for determining an activity. The results of the assays were analyzed through Qualitek4 software using the Taguchi method to evaluate a factor's effects on enzyme activity. The results of the assays revealed that the activity of this enzyme from germinated barley was reduced following thermosonic treatment, and as compared with the blank.

Citrus fruits are holding a prominent position among agricultural products throughout the world. One of these important fruits from economical and industrial point of view is orange. This product is consumed as fresh, juice, concentrated juice and/or dried slices. In this study, thin layer drying of Thomson cultivar of orange (novel) was modeled. A laboratory dryer was employed to attain the goal. Experiments were conducted at five levels of dryer air temperature (30, 40, 50, 60 and 70°C), an air velocity of 0.5 m/s with orange slices of 4 mm thickness replicated three times. Under controlled conditions, samples of 5.4 to 5.7 (g/g) initial moisture content (d.b) were dried. Moisture content of the mass of orange slices was continuously calculated by constantly weighing the samples during the drying process. Thirteen standard mathematical models for simulation of the thin layer drying process were asseyed through curve fitting, while three parameters of coefficient of determination (R 2), chi-square(c2) and root mean square error (RMSE) being used to compare the results of multivariate regression analysis. A new model, appearing for the first time in this paper was developed and put to test in the comparison process. Determination coefficient, chi-square and root mean square error for the new model were the most responding as compared to the rest of the models being found 99.98%, 0.00154092, and 0.03460955, respectively. Therefore, the new model provides a most promising one for predicting moisture content changes during a thin layer drying process of orange slices.

The effects of pasteurization, storage time and temperature on proteolysis of milk were evaluated. Two replicates of each of raw and pasteurized milk were assigned to three temperatures (5, 16 and 25°c) and 3 storage periods (1, 2 and 3 day) in a 2x3x3 full factorial design. For all the samples, pH and indices of proteolysis were determined. The effect of all the three main factors (pasteurization, storage time and temperature) as well as their two and three-way interactions were significant on pH and proteolysis indices. As storage time and temperature increased pH of either one of raw or pasteurized milk, decreased. Proteolysis indices also increased in both cases, but the change of these two factors for pasteurized milk was lower than those for raw milk. Degradation of each one of nukj proteins was demonstrated through SDS-PAGE (10-20%). Correlations were observed to be negative between levels of % casein and % proteolysis products. Witn increase in temperature % casein decreased while proteolysis products are increased. But a-lactalbumin and b- lactoglubolin did not vary with change in temperature and during the storage time.

Conventional tillage operations by either moldboard or disk plow need to be either changed or improved. Two types of combination plows were recently developed to modify the conventional equipment as well as to increase the efficiency. The aim of this research was to investigate the effect of the two combination plows as compared to conventional plow on power requirement and on specific draft. The experiments were conducted in a loamy textured soil with moisture content of 16-18% in Karaj region. Treatments consisted of moldboard + chisel plow combination, and disk + chisel plow combination vs conventional moldboard plow. Data was statistically analyzed using RCBD in three replications. Draft resistance, furrow cross section area, specific draft and drawbar power were either measured or calculated and then analyzed. The results indicated that draft resistance increased by.16.8%with moldboard + chisel and decreased 8.9% with disk plow + chisel as compared to conventional moldboard plow. However specific draft decreased by 29.8% and 10.4% for the combined plows respectively as compared with the conventional plow, this being due to soil disturbed area. Drawbar power for disk plow + chisel was noted to be maximum (26.2 kW).

To study the mechanical and thermal parameters effective on quality and quantity of olive oil towards an extraction of highly pure oil, the velocity in rps of crushing rollers, at two levels of 6 and 12 (rps) along with the temperature of the mixing unit at three levels of 30, 45 and 60°C were taken into account. Data, obtained through a factorial experiment of Randomized Complete Block Design (RCBD) were analytically evaluated and compared. A comparison of means as based on Duncan Multirange test was indicative of the fact that: acid and peroxide level of oil increases with an increase in temperature at the mixing unit, meaning a. decrease in the quality of olive oil. Increase in temperature of mixing unit also leads to an increase in moisture content of pumice leading to a decrease in the quantity of oil extracted. An increase in temperature of the mixing unit from 30 to 45°c was followed by an increase in oil content of pumice and leading to an increase in extracted oil. A further increase in temperature of the mixing unit from 45 to 60°C did increase oil content in pumice, but this increase was accompanied by a decrease in total quantity of oil extracted. The least acidity figure was obtained for a roller crusher speed of 12 rps at 30°C. As for peroxide content to be the least there were no significant differences observed among the treatments of 12x30, 12x60 and 6 (rps)x45°C, but the least peroxide content was observed for the treatment 12 rps x 30°C. This led to the concoction that the most suitable velocity of crusher rollers along with the most proper temperature of the mixing unit for an extraction of optimum quantity high quality olive oil would be 12 rps and 30°C respectively. These are the figures finally recommended for efficient quality olive oil extraction.

As a first step towards mechanization related to any product, including date fruit, it is necessary to have comprehensive information about the product. Physical and mechanical properties are needed for the design of post harvest machinery and equipment. The objective of this study was to determine and compare some physical properties such as dimension, mass and volume, particulate density, pitted density, bulk density, porosity, projected areas, geometric mean diameter, sphericity and surface area of Haj-Ghanbari and Shahani varieties of date fruit. Also coefficient of static friction on three different surfaces including galvanized iron steel, glass and plywood were determined and compared. Experiments for date while pitted dates were carried out at 12.90% and 12.20% (w.b.) moisture content for Haj-Ghanbari and 30.55% and 29.42% (w.b.) for Shahani variety. Results indicated that mean mass and volume were 5.57 g and 4.74 glcm3 for Haj-Ghanbari and 8.69 g and 8.67 glcm3 for Shahani variety. Size and projected areas of Shahani variety were greater than those for Haj-Ghanbari. The average fruit true density, pitted density and bulk density of Haj-Ghanbari variety were greater than those for than Shahani variety while porosity was less than that for Shahani. The geometric mean diameter, surface area and mean coefficient of static friction of Shahanidate were more than those for Haj-Ghanbari while sphericity was equal for the two varieties with an average value of 0.58. Results are useful in design of post harvest equipments and machinery for date fruit.

The objective of this research was to develop a suitable method for color sorting of fruits. Accordingly, a color-sorting system was designed and a prototype developed and then tested. This system includes an optic head which is designed to develop a reflection of the fruit. Output of the head is then processed in an electronic control system which generates the appropriate signal for ejection or admittance of the fruit in accordance with its color. This is accomplished by sending the signal to an electrical ejector mechanism that effects the sorting operation. Tests were conducted to check the system's performance and to study the effect of some such parameters as type of fruit and ambient light intensity on accuracy of the system. Results indicated that main and interaction effects of these parameters on accuracy are not significant. Hence, this system is suitable for sorting of fruits, with its performance not being affected by either fruit type or ambient light intensity.

Colour is one of the most important quality factors that can influence and determine the shelf life of canned chicken kebab. Colour change is considered as unsuitable distasteful to consumers, indicating the end of a product's shelf life. In this study quality aspects of samples were examined over one month intervals after being prepared and while being stored under accelerated (44°c) conditions. Sensory evaluation of samples' colour was also determined calling the assistance of 10 trained panelists. Results indicated that the whiteness, yellowness and redness indecs of chicken kebab decreased during storage. The end of shelf life for canned chicken kebab was determined as 5 months under accelerated conditions (20 months under normal conditions) while employing the correlation between sensory evaluation and analytical findings.

Whitening as one of the stages in rice processing is performed following dehusking. Studies on performance of milling machines prevailent in Mazandaran province, as the biggest rice producer province in Iran, are essential and helpful in reducing rice losses. A research was undertaken to examine the effects of variety (Tarom, Hibrid, and Fajr), milling machine (frictional and abrasive baed milling machines) as well as milling time duration (25, 35, 45, 55, 65 and 75 seconds) on some such rice qualitative, and quantitative parameters as broken rice, degree of milling, as well as whiteness index. Statistical design was a randomized complete block design one 36 treatments and in three replications. Results indicated that increasing milling duration increased the degree of rice whitening up to 53.39 %due to a more stay time of brown rice in the milling chamber. Among the treatments, Hibrid and Fajr varieties devoted the highest and the lowest degree of milling to themselves, respectively. Based on statistical analysis, Tarom variety scored the highest whiteness index of 0.360, whereas Hibrid variety showed the lowest one namely 0.247. Results indicated that milling machine type, rice variety and milling time duration as well as interaction effect of milling machine type and rice variety exert significant effects on all parameters studied. Amount of broken rice for Fajr variety and for the two types of milling machines was found to be equal, whereas, that figure for Tarom variety was almost 10.23% lower for abrasive type machine as compared with the frictional one.

Canola is known as an important oilseeds crop throughout the world. Cultivation and subsequent oil extraction of this crop has gained substatantial development in recent years in Iran. Many parts of Iran (northern provinces) especially Golestan and Mazandarn are of high relative humidity during harvesting season as well as during storage periods. Spoilage and rancidity are problems more encountered in these regions. Decreasing grain moisture content to a safe level causes increased safe storage time as well as preserved quality. It would be highly beneficial for canola producer and processor in high relative humidity localities to use new methods of drying. In this research, fluidized vs fixed bed conditions were employed for canola drying at eight experimental temperatures of 30, 40, 50, 60, 70, 80, 90 and 100°C using a Lab. scale fluidized bed dryer. Effects of temperature and bed condition were investigated on the drying time and drying rate parameters. A Completely Randomized Design (CRD) as the experimental procedure was employed with three replications. Results indicated that using fluidized bed technique increased the drying rate while decreasing the time needed for drying, this effect being more pronounced in temperatures of less than 50°C. For an instance, fluidizing of canola grains during the drying process caused energy savings while decreasing the drying time by approximately 32% at a temperature of 30°C as compared with fixed bed drying. This effect was less for high temperatures and was calculated approximately 27.8 % at 70-100°C. By increasing temperature, percentage of oil extraction of dried grains significantly increased while peroxide values of extracted oil remaining unchanged. Fluidizing favorably affected such quality factors as free fatty acids and color.

Tomatoes (Roma cultivar) picked up for the study was obtained from Varaminelocal market. Each tomato was divided into four portions. Quarter portions of tomato were placed in osmotic solutions that were different in levels of sucrose and NaCl (30 and 40% for sucrose, and 5, 10 and 15% for NaCl). Osmotic dehydration was carried out for varied time durations from. 15 up to 240 min. Temperature of dehydration process were kept constant at 30±2°C. Ratio of tomato to solution was 1:10. The mixture was agitated by use of an agitating system of 150 rpm. Two osmotic solutions of specified concentration and treatment times were chosen, following a determination of water loss vs solid gain for all the treatments. Samples dehydrated with these (5% NaCl+40% sucrose or 10% NaCl+40% sucrose) solutions were then dried in a hot air dryer. Finally, dried samples were analyzed for their texture and microstructure by employing instron and scanning electron microscope (SEM) respectively. Comparing the osmosis treated samples with non-osmosed ones demonstrated that applying osmotic pretreatment Gauseda softening of structure. It reduced the shrinkage of dried product by restraining the rupture of product's cellular structure.