جستجوی مقالات مرتبط با کلیدواژه « خصوصیات فیزیکی شیمیایی » در نشریات گروه « کشاورزی »

Vegetable oils play an important role in food preparation and food formulation and play a significant role in diet and health. Identification and cultivation of new oilseeds is an important step in the direction of supplying the required oil in the country. Milk thistle plant with the scientific name of Silybum marianum is a one-year or two-year herb that has many medical, medicinal and industrial uses since ancient times. Due to its biological characteristics, this plant requires very little fertilizer and is particularly resistant to dry conditions and weak soils, and it is compatible with the climate conditions of most regions of Iran. Milk thistle seed contains a significant percentage of oil (20-30%) with high nutritional value due to the presence of essential fatty acids such as linoleic acid (40-60%), oleic acid (20-32%) and antioxidant and bioactive compounds such as tocopherols, carotenoids and sterols. Therefore, the oil obtained from milk thistle seed can be considered as a new edible oil due to its long-term consumption in different societies and its bioactive compounds. In this review article, a brief look at milk thistle plant, oil percentage and its composition in different regions has been discussed. According to scientific reports and articles, the cultivation and development of this new and valuable oil seed with good economic value is recommended as a new source of edible oil.

Fodder beet is a valuable source of fodder in livestock diets due to favorable agronomic characteristics such as resistance to salinity and drought, less water requirement, and proper nutritional characteristics such as forage production and silage with high nutritional value, good taste, and good resistance to environmental changes. Despite the long history of using fodder beet in animal rations, its nutritional issues and physicochemical properties of it are not fully understood and further research is needed. Silage of fodder beet can be used well in the diet of all ruminants, but studying the proper ways of silage and controlling the physical and chemical properties of silage is one of the important issues that should be addressed. In addition to the stated benefits for fodder beet, such as low dry matter content, fiber, and fat, disruption of ion exchange and change in silo buffering capacity, as well as the difficulty of processing it for permanent consumption of livestock and also important restrictions such as high sugar and moisture in the roots and excess leachate and lack of production of quality silage are the most important obstacles to the consumption of this silage. Harvest time of fodder beet coincides with the heat of the summer season and the occurrence of numerous problems, so it is necessary to silo it to prevent spoilage with the correct method. Today with the introduction of new improved cultivars and the growth of processing technology, these limitations have been almost removed. This study aimed to evaluate some of the physicochemical parameters of ensiled fodder beet with and without Lactobacillus buchneri as a microbial additive.

Some physicochemical parameters of ensiled fodder beet with and without Lactobacillus buchneri as a microbial additive in combination with 10 and 15% dry beet pulp were investigated through a 3×2 factorial arrangement in four replicates. Different silages included: 1) 100% pure fodder beet without additive (control), 2) control + 10% dry beet pulp, and 3) control + 15% dry beet pulp. The microbial additive was added at the level of 6×1010 CFU/g of dry matter. 24 plastic bags containing 25 kg of different material were compacted, sealed, and stored at room temperature. After 75 days, four bags of each group were opened and pH, temperature, and quality were immediately determined. Also, a sample from each bag was used to measure the chemical compositions. Measurements of temperature and pH were performed. Two samples of silage, one for extraction and determination of ammonia nitrogen (using selective ion absorption electrode) by AFIA recommendations and the other sample for measurement of dry matter, crude protein, and ash according to the AOAC method were used. Measurement of NDF and ADF were done according to the Van Soest method. To evaluate the aerobic stability of silages when opening plastic bags, the characteristics of color, odor, and texture of silage in the range of 1 to 10 for high to poor quality were determined using the modified Konigsberg Scores method. Data were analyzed using a completely randomized design in a 3×2 factorial arrangement in four replicates using the mixed model procedure of the SAS program.

Experimental groups with 10 and 15% of dry beet pulp with microbial additive had a better quality (score: 6.5±0.16 vs. 9.4±0.21; pH: 4.04±0.06 vs. 4.59±0.08) than the control group (P<0.01). The type of ensiled materials had a significant effect on chemical compositions (DM, CP, NDF, and ADF) and the aerobic stability of silages at opening time (P<0.01). But microbial additives almost had no significant effect on the traits. Watery loss of silage for the control group was higher and its quality was lower than that in other groups (P<0.01). The best quality and more stability of silage were observed in the group with fodder beet+15% of dry beet pulp which is advisable.

According to the results of this study, adding 10 and 15% of dry beet pulp to fodder beet silage improved the appearance and aerobic stability of the resulting silages compared to the control group. Evaluation of appearance traits and pH of the samples showed that the treatments with dry pulp and the microbial additive had better quality than the control group. The type of mixture used had a significant effect on the chemical composition of silage and its aerobic stability when opened, but the microbial additive did not show a significant effect in most cases. The watery loss in the control group was higher than the other treatments and had a worse appearance quality than other silages. Overall, the most suitable silage composition in this experiment was a mixture of the control group+15% sugar beet pulp, which had better appearance quality, longer shelf life, higher dry matter level, and lower ammonia nitrogen than the other two groups.

Doogh is a fermented milk drink mixed with water and a little salt. The production and exportation of dough as a native Iranian fermented beverage has grown steadily in recent years. One of the disadvantages that causes corrosion and increases doogh deterioration is the spoilage caused by the activity of molds and yeasts. The common method for increasing shelf life of food (such as doogh) is drying by using spray dryer that eventually lead to reducing the volume, costs of carrying and easy usage. The objective of this study was to produce a doogh powder by spray drying method and investigate the effect of Alyssum homolocarpum seed gum on its physicochemical properties.  In this study, yogurt (1.5% fat), salt, distilled water, maltodextrin (GPC brand), and Alyssum homolocarpum seed gum were used. Alyssum homolocarpum seed gum was cleaned and the foreign particles were separated. The whole grain gum was extracted using distilled water in a water-to-seed ratio of 30 to 1 with a pH of about 8 and a temperature of 48°C and dried at 70°C in a vacuum oven and then powdered. Brine (7% salt) was prepared with boiled distilled water at 80°C. After dissolution, a certain amount of Alyssum homolocarpum seed gum was added (at concentrations of 0, 0.05, 0.1, 0.15, 0.2% separately). The solution was stirred for 10 minutes with a magnetic stirrer at 60°C. After complete dissolution, 40g of yogurt (1.5% fat with pH=4.1) was added to gum solution. The final volume of doogh was at 100g. To completely dissolve the particles, a magnetic stirrer with a speed of 2000 rpm for 15 minutes at 60°C was used. The temperature was then reduced to 20°C and the final product was packed in 500 ml bottles. Doogh was dried using a spray dryer in optimal conditions, feed intake flow of 44.5 ml/ min and drying temperature of 190°C. The physicochemical properties of dough powder such as pH, acidity, moisture content, dry matter, solubility, dispersability, and serum separation as well as glass transition temperature and particle size were determined. Doogh treatments consisted of 0.05, 0.1, 0.15 and 0.2% containing Alyssum homolocarpum seed gum and also a control sample. All the experiments were performen in triplicate. The results were analyzed as means± standard deviation (SD). Thus, the data were determined using the software SPSS (2013). Statistical differences were analyzed by variance (ANOVA) and Duncan’s multiple range test (P values <0.05). The results showed that by increasing the Alyssum homolocarpum seed gum , moisture and serum separation were decreased and  acidity, dry matter, solubility, dispersability ,particle size and glass transition temperature were increased. With increasing gum concentration from 0.05 to 0.1 and from 0.15 to 0.2%, the acidity increased significantly (P<0.05).The rate of dehydration of samples containing different percentages of gum after three weeks showed that the use of Alyssum homolocarpum seed gum significantly reduced serum segregation. The results showed that by increasing the concentration of gum, the particle size of the dough powder was significantly reduced (p<0.05).With the increase in the amount of gum, the rate of diffusion increased significantly (P<0.05).With increasing gum concentration and decreasing moisture, the glass transfer temperature of the powder samples increased. The control sample had the lowest and the 0.2 gum treatment had the highest glass transfer temperature (P<0.05).

Ice cream is one of the most popular dairy desserts in the world. In recent years, the reduction of fat and fiber intake in dietary products has received much attention. Citrus peel is a valuable source of dietary fiber that is usually discarded as waste. In this research, the fiber extracted   from Citrus uranium L. peel was used as a novel fat replacer in light vanilla ice cream.

3 levels of Citrus uranium L.  Fiber (0.5%, 1%, and 1.5%) were added to low fat vanilla ice cream formulation.  The physical, chemical and sensory characteristics of low fat vanilla ice cream were investigated.

The results of this study showed that addition of fiber had a significant effect on the physical properties of ice cream including viscosity and overrun. As the fiber levels increased, the viscosity, melting resistance and overrun of the treatments increased. The effect of fiber on the ice cream pH was significant (P <0.05), with increasing fiber levels, the pH of treatments decreased.Data showed that the effect of citrus uranium L. fiber on all factors of ice cream sensory evaluation was significantly different (P <0.05).Based on the results obtained by increasing the percentage of fiber, the highest score in sensory tests was obtained in treatment 2 (containing 1% fiber). The lowest was for treatment 3 (containing 1.5% fiber).Overall, the results showed that fiber can be used to produce low-fat ice cream with appropriate physico-chemical and sensory properties.Keywords: low fat ice cream, fiber, physico-chemical properties, sensory evaluation.

The operation of sand transport by erosive winds and its sedimentation around the obstacles such as plants leads to the appearance of the eco-geomorphologic phenomenon of nebka dunes in dry seasons of Golestan province. This study aims to identify the physicochemical characteristics of nebka sediments and compare its results with adjacent lands. Hence, the grain size distribution and morphometric characteristics of particles were determined for 30 samples in Sufikam plain in the Eastern border of Caspian Sea. Then, the relationships between the physicochemical properties were compared using Wilcoxon and T-test at 95%. Results showed that the prevailing wind direction is west to east which in our case is from sea to land. Analysis of sand rose graph indicates that the winds in spring and summer blowed the sediments from soil surface. Results showed that there were no significant differences between sorting of particles, fraction of very fine sand, silt, clay, EC, pH and organic carbon of nebka's head samples and its adjacent land. However, results of skewness index, mean diameter of fine sand, medium sand, coarse and very coarse sand, SAR and ESP proved to be statistically significant. Therefore, it can be concluded that the source of sediments is local.

Flood spreading has been identified as an effective method to improve soil fertility, recharging groundwater, restoring vegetation condition and combating desertification. Identifying the rate of changes under this treatment has great value for restoration programs. The purpose of this study was to study the effects of flood irrigation on the soil properties in Band-E-Alikhan area in Varamin. The study area is located in south part of Varamin, north of Masileh Plain and Salt Lake coast in Qom. Mixed soil samples were collected from the first, middle and the last plots established along the five transects with 50 meters length in both treated and control sites. Soil samples were also collected and compared from under canopy and bare soils in flood spreading area. Results of T test showed that the average percentage of organic carbon, nitrogen, phosphorus, potassium and saturated water content and silt were increased and electrical conductivity, soil bulk density and clay content were decreased in flood spreading area compared to control site. Results also indicated that electrical conductivity, nitrogen, phosphorus, potassium, saturated water content, sand and clay content were increased and silt percentage was decreased under plant canopy compared to the bare soil areas. Therefore, it can be stated that establishing flood spreading system in the region has gradually increased the soil fertility.