JWSS - Journal of Water and Soil Science

---

Short-term changes (5 years) in canopy cover, species composition and forage production were studied under protection from grazing and grazed condition in 19 range sites in Fereydan region, Isfahan province. In this study, density, canopy cover and forage production data were obtained from quadrates inside and outside exclosures in the spring of 1983. These parameters were studied again in 1988 and compared with the previous data. Results indicated that species diversity in these range sites was relatively high up to 212 plant species were identified. Sixteen, 8.5 and 75.5 percent of these species were classified into I, II and III palatability classes respectively. After five years, comparison of inside and outside exclosures indicated an increase in the density of species of I, II and III palatability classes by 138.8, 120.8 and 51.5 percent inside exclosures, respectively. Density of all species had increased by 62 percent as a result of 5-year protection from grazing. Species composition data as canopy cover were used to construct 3 dendrograms to investigate the similarity among range Sites. Assuming 32% similarity as the threshold level, 19 range sites were classified into 10 vegetation types in 1983. After 5 years, these vegetation types decreased to 8 and increased to 11 under protection from grazing and grazed conditions, respectively. The average forage production inside exclosures was almost twice as much as in grazed sites (600 Vs. 315 kg/h). Three groups of range sites were recognized according to the time requirement for rehabilitation by grazing protection. The first group was improved considerably by the end of the 5-year protection Period. The second group improved relatively within five years of grazing exclusion. The third group did not improve by 5-year grazing protection and needed much longer protection period or some other range rehabilitation practices.

---

Methods of seedbed preparation affect establishment, growth and yield of crops via manipulating physical and chemical properties of soil. These effects on wheat-mungbean double-cropping have not been studied in Isfahan. Therefore, the influences of various seedbed preparation methods on soil physical properties and nutrients content and on establishment of mungbean (experimental line 1-61-16) were studied in a wheat-mungbean double-cropping system during 1996 at the Agricultural Research Station, Isfahan University of Technology. Two residue management treatments (burned and unburned) along with four tillage systems (moldboard plow, disk, khishchee and no-till) were laid out in a strip plot design within a randomized complete block design with four replications. Bulk density and penetrability of soil at various depths were not affected by residue management at emergence. However, at the time of flowering, bulk density at 0-15 cm soil depth was lower and soil penetrability at 3-15 cm depth was higher in unburned treatment due to mineralization. Rate and coefficient of emergence of seeds were lower in unburned residue treatment. Soil bulk density at 0-30 cm depths was lower and penetrability at 3-21 cm depth was higher with moldboard plowing at both emergence and flowering time. In addition, lower soil N, P and K content at 0-15 cm depth at emergence and flowering time was obtained with moldboard plowing. Rate and coefficient of emergence were strongly lower in no-till treatment. Based on these results and considering sustainable agricultural goals, incorporating residue with disk tillage might be advantageous under conditions similar to this experiment.

---

Limited time for crop residue decomposition and complete seedbed preparation in double-cropping necessitates reduced tillage which is associated with its shortcomings. Information about seedbed preparation aspects in double-cropping of wheat and mungbean in Isfahan is lacking. For this reason, the effects of various seedbed preparation methods on growth, seed yield and yield components of mungbean (experimental line 1-61-16) were studied in a wheat-mungbean double-cropping system during 1996 at the Agricultural Research Station, Isfahan University of Technology. Two residue management treatments (burned and nonburned) along with four tillage systems: moldboard plow, disk, khischee and no-till were laid out in a strip plot design within a randomized complete block design with four replications. Improved establishment and plant growth conditions associated with burning residue treatment significantly increased plant density, above ground plant weight, number of nodes per branch, plant height, number of pods per main stem and per square meter, number of seeds per pod on main stem and on branches, number of seeds per main stem, seed yield, biological yield and harvest index. Higher plant density in this treatment resulted in significant reduction in the number of branches and number of pods per branch. Desirable conditions for establishment and growth in disk and moldboard plow treatments significantly increased plant density, above ground plant weight, number of pods per main stem and per square meter, number of seeds per pod on main stem and on branches, number of seeds per main stem, seed yield, biological yield and harvest index. No-till treatment produced the least results in respect to the above traits. The results indicated that burning residues with disk tillage system might be an appropriate seedbed preparation method under conditions similar to this experiment.

---

Estimation of flood flow rate represents a method of preventing damages associated with this natural phenomenon. This estimation is one basis in the design of various hydraulic structures, dam spillways, watershed management and flood control. The maximum flow rate of floods is determined by methods such as Creager, Jarvis-Meyer, Cypress-Creek, and rational method. Rational-probability method is an alternative to estimate peak flood rates, and is expressed as:

 Q(y) = F. C(y). I(tc.y).A

 where Q is maximum flood flow rate (m³/sec) y is the return period (year) C(y) is runoff coefficient with a return period of y A is watershed area (km²) I is rainfall intensity (mm/hr) for a specified return period equal to time of concentration of the watershed and F is the conversion factor equal to 0.278 when the above units are used. The basic concept of this method is the same as that in the rational method except that the return period is also included in the equation. Usually, runoff coefficient, C(y), is determined empirically from tables cited in the literature (e.g., Chow et al., 1988). In the present research, data from 18 hydrometry and 6 rainfall-recording stations (located in Caspian - Sea watershed) were analysed using TR software. The Caspian - Sea watershed (which covers eastern and centeral parts of Iran's No. 1 main watershed) has the sub-basins of Atrak, Tadjan, Chalus, Sardabrood, Siahrood, Gorganrood, Safarood, Kesilian, Babolrood and Neka. Runoff coefficients with return periods of 2, 5, 10, 25, 50 and 100 years were determined for these sub-basins and iso-coefficient curves were plotted. The results showed that computed runoff coefficients were less than the values given in the literature because they are determined from observed flow rate and rainfall intensity in each catchment. It was also shown that runoff coefficient increased with increasing return periods. Application of the computed runoff coefficients in three sub-basins of the area resulted in more accurate estimations of maximum flood rate than when the values for these coefficients cited in the literature were applied.

---

Pectin is used in a number of foods as a gelling agent, thickener, texturizer, emulsifier and stabilizer. Sugar-beet pulp, the residue left from sugar extraction, is a rich source of pectin. It was the purpose of this study to develop a procedure for the extraction of pectin from sugar-beet pulp and to improve the functional properties of this pectin for more potential uses. To extract pectin, pressed beet pulp was dried and powdered. Then, it was extracted under various conditions (pH 1 and 1.5, temperatures of 80^oC and 90^oC and extraction periods of 1, 2, 3 and 4 hr). The highest yield (22.35%) was obtained at 90^oC after 4 hr at pH 1. Chemical composition of the extracted pectin and that of commercial citrus pectin were determined and compared. Also, the beet pulp pectin was used in certain foods and its functional properties were compared with those of the commercial citrus pectin. The effects of ammonium persulfate and high pH levels on the above mentioned properties were investigated. Finally, the effects of the beet pulp pectin and the commercial citrus pectin on the flavor of certain foods were evaluated. The results indicate that the extracted beet pulp pectin can be used in certain foods such as ketchup sauce as a thickener or as an agent increasing the viscosity however, it does not have the ability to form firm gels in food.

---

Whey powder, due to its lactose and protein contents, can be used as an important flour improver to decrease the rate of staling. In the present investigation, whey powder was added at 5 levels (zero to 5%, W/W) to the flour of Sangak bread. Bread was baked according to the formula and procedure used by traditional Sangak bakeries. Bread samples were kept at room temperature or under refrigeration for 36 hours. They were then evaluated for staling by a taste panel. They were also subjected to proximate analysis. The dough was examined for farinographic, amylographic, extensographic and fermentographic properties. The data of staling tests including color, texture, flavor and also proximate analysis data were analyzed by ANOVA. Finally, differences among treatments were examined by Ducan’s multiple range procedure. The results indicated that the best treatment was the use of 3% whey powder, as far as staling and texture of bread are concerned. However, the best color of bread was achieved with 5% whey powder so was true of the protein, ash and fat contents. Viscosity, as tested by amylography, and also parameters of farinography reached their highest levels in the dough prepared from flour having 5% whey powder in the formula. The best extensibility was observed with the flours containing 4% whey powder and the highest dough energy was associated with the dough prepared from flour having 5% whey powder. As for the loaf volume, best results were obtained with the dough prepared from flour having 3% whey powder. Overall, it is concluded that the use of 3% whey powder is the best treatment with regard to the delay in the rate of staling, increase in loaf volume, and color appeal of Sangak bread, and rheological properties of the dough.

---

Consumption of bread made from flours with high extraction rates is fairly common in western countries and has recently become widespread in Iran. Such breads contain relatively high levels of phytic acid. Phytic acid is present in the aleurone layer of wheat in the form of potassium-magnesium salts. It is carried over to wheat flour and to bread. Phytic acid is known to have chelating properties and to form complexes with bivalent cations (iron, calcium, zinc and so on), thus reducing their bioavailability in humans. In addition, phytate salts can form complexes with proteins, carbohydrates, and fats in the diet, making them unavailable too. In the present study, phytic acid contents of flours ( 3 individual extraction rates and 2 combinations), the dough and two types of popular breads of Khorasan (Lavash & Sangak) made from these flours were determined. The results showed that the flours had, on the average, 570.37 mg phytic acid per 100 g and that the phytic acid contents of breads were, on the average, 347.31 mg/100g. This indicates that the present baking procedures do not have an appreciable effect on the level of phytic acid recovered in bread.

---

Bread, the main staple food of Iran, imparts a major portion of energy and protein to urban and rural diets. Due to the use of flour with high extraction rate and improper fermentation of the corresponding dough, traditional breads have a rather high level of phytic acid. This has a detrimental effect on absorption and availability of minerals (Ca, Fe, Zn, Mg, Cr, Cu, etc.), carbohydrates, proteins and lipids, thus leading, for e.g., to iron-deficiency anemia in the present study, flours with different extraction rates (with known phytic acid content) were used for baking “Sangak” and “Lavash” breads and analyzed for phytic acid. Different levels of yeast, times of fermentation and extraction rates of flour were applied in the preparation of breads and their phytic acid levels were then estimated. Based on technological merits and residual phytic acid contents, breads prepared from two types of treatments were selected, their chemical composition, availabilities of iron and lysine as well as organoleptic characteristics were evaluated. Results indicated that under the employed conditions total destruction of phytic acid in “Sangak” and “Lavash” is rather impractical. A considerable reduction in phytic acid was noted: in “Lavash” bread using 2.5% yeast, 4 h of fermentation and a 50-50 blend of flours with 81.0 and 86.5% extraction rates and in “Sangak” bread with similar conditions (except for the flour which was a 50-50 blend of 86.5 & 97.5% extraction rates). Available lysine was similar in both of the selected breads compared to their respective references. Their available iron contents, however, were higher than their corresponding references (P ≤ 0.05 ). No significant differences were observed with regard to organoleptic evaluations of selected breads as compared to their references (P ≤ 0.05 ). Overall, the above-mentioned treatments are recommended for the baking of “Sangak” and “Lavash” breads.

---

Systemic properties of pyroquilon, an anti-blast systemic chemical, used in controlling rice blast disease caused by Pyricularica grisea, was investigated through in vivo tests. Rice plants were treated with pyroquilon as granules in soil. Leaf and stem tissues were collected at different times after treatment and pyroquilon was extracted from tissues and detected by gas chromatography. Treated rice plants were also exposed to disease infection in blast nursery at different times and disease incidence was evaluated one week later. Pyroquilon was detected in leaf tissue one day after treatment (DAT), reached maximum during 4-7 DAT, and then reduced gradually to a nondetectable level after 28 DAT. In stem tissue, change in pyroquilon content was similar to but its quantity was less than that of leaf tissue. On inoculated plants, disease was controlled up to 60% at 2 DAT and completely controlled during 4-28 DAT. The results indicated that pyroquilon could be taken up and systemically translocated in rice plants after applying as granules in soil. Extent of disease control was a good function of pyroquilon content in leaf tissue (R²=0.93) and 2 ppm of compound in leaf could provide 90% control of the disease. In contrast, disease control was not a good function of pyroquilon content in stem tissue (R²=0.30).

---

In order to identify the plant-parasitic nematodes of important cereals (wheat, barley, and corn) in Isfahan Province, 120 soil and root samples were collected from the rhizosphere of these crops in various locations in the region during 1999 and 2000. Nematodes were extracted from soil by sieving and centrifugal sugar-flotation method. The specimens were killed and fixed in FGA (formaldehyde, glycerin and acetic acid 4:1:1) hot solution. The extracted nematodes were mounted in glycerin, permanent slides prepared, and studied by light microscope. The results revealed the presence of three species belonging to two genera of family criconematidae as follows: Criconemella antipolitana , C. xenoplax, Hemicycliophora poranga. H. poranga was extracted from rhizosphere of corn and reported for the first time from Iran. The most frequently occurring and dominant species was C. antipolitana that was isolated from soil around the roots of wheat and barley in several areas. C. xenoplax was extracted from a wheat field with the history of peach cultivation. These species are new records for Isfahan Province.

---

Mayonnaise is a food emulsion containing egg yolk as emulsifier and some sort of gum as stabilizer. Iran is a main producer of tragacanth gum in the world which could be a potential replacement for imported gums used in making mayonnaise .The objective of this study was to investigate the possibility of substituting this gum for imported stabilizers in the formulation of mayonnaise sauce. To do this, tragacanth powder was added to the sauce at the levels of 0.1, 0.2, 0.4, 0.6, 0.8 and 1% . Emulsion stability and apparent viscosity of the sauces were determined and compared with that of the commercial one to find the right concentration of tragacanth. This concentration was used to produce mayonnaise on a commercial scale and then its physico-chemical characteristics, microbiological stability, and organoleptic properties were compared with commercial mayonnaise. The shelf-life of the sauce samples were also monitored bimonthly up to 4 months at two different temperatures (5 and 25 ^oC) by measuring apparent viscosity, moisture content, pH, microbial count, and organoleptic parameters. The results were compared with those obtained for commercial sauce. The results indicated that the characteristics of tragacanth-containing mayonnaise were similar to those of the commercial one and that the former was acceptable to consumers. Therefore, gum tragacanth at the right concentration could be a suitable subsitute for the stabilizers and thickeners already used in making mayonnaise sauce.

---

To evaluate seed germination and seedling growth of safflower in moisture stress, germination of 15 genotypes at four water potential levels (ψ: 0, -0.4, -0.8 and –1.2 Mpa) was tested by Polyethylene glycol (PEG6000). Maximum germination (Gmax), germination rate index (GRI), time length to reach 50% germination (T₅₀), rootlet length (RL) and shootlet length (SL) were investigated. Effects of water potential levels and genotypes were significant for all the characteristics studied. Minimum water potential for germination was estimated between –1.17 and –1.59 Mpa in Goshkhani and LRV-51-51 genotypes, respectively. Different responses to moisture stress were found for rootlet length. In lower potential levels, seedlings had longer, weaker and thiner rootlets in comparison to the zero water potential (control). An increase in stress to –1.2 Mpa led to a severe reduction in rootlet elongation. All stress levels decreased GRI and SL, while potentials lower than –0.4 Mpa decreased Gmax. With a decrease in water potential from 0 to –0.8 Mpa, the T₅₀�stage was delayed three-fold compared to the control. Exotic genotypes had longer T₅₀ stage than Iranian genotypes. The highest GRI was related to three Iranian genotypes LRV-51-51, Varamin 295, and Isfahan local, and the lowest was related to CW-74 exotic genotype. Some of genotypes were evaluated for seed yield, oil yield and seed oil percentage under rainfed condition in 2004-05. The highest oil yield average belonged to two exotic genotypes PI- 537598 and Lesaf (326.4 and 313.9 Kg/ha, respectively) and the least was related to Zarqhan 279 Iranian genotype (133.2 Kg/ha). Negative and significant correlation was observed between seed oil percentage and GRI in the 0, -0.8 Mpa potential levels. According to the results, the existing genetic variation for germination parameters can be used for genetic improvement of seed early vigor in safflower.

---

Iran is a major apple producing country. A number of industrial apple products can be made from apple. In some developed countries about 25% of apples are processed into apple sauce. Apple sauce hasn’t so far been produced by Iranian food industry, but if a formulation suitable for the taste of Iranian consumers is prepared, it can commercially succeed as a consumer product. At the first step of this study, six apple sauce formulations were made from Golden Delicious apples. Then the sensory properties of these apple sauces were evaluated by partially experienced panelists. The best formulation was chosen by a ranking test. Also, this selected apple sauce formulation was evaluated by ordinary consumers in some popular restaurants. The majority of these consumers accepted the taste and flavor of this apple sauce. The chemical, physical and microbial properties of the apple sauce formulations were determined and compared. In the final step, samples of the chosen apple sauce were stored at 4^oC±1 or 25^oC±2 for 10 months and their chemical, physical and microbial properties were determined bimonthly. The results indicated that the selected apple sauce could be stored at ambient temperature for over 10 months, without undesirable quality changes.

---

For milk fat modification, after decantation of its serum, it was fractionated at three temperature rates (30-35, 17-22 and 5-10 ºC) and times (6, 13.5, and 18 hours). After each stage, the solid phase or stearine fraction was separated from liquid phase or olein fraction by centrifugation at 1600 rpm for 15 minutes. The olein fraction was then used in the second step of fractionation. This process was repeated three times until the low, medium and high melting fractions (LMF, MMF and HMF, respectively) were isolated to 27 fractions. Iodine value (by Wejs’ method) and solid fat content (SFC by NMR) of these fractions were measured and compared. The results, showed significant differences between in IV and SFC for LMF with MMF and HMF (3-6 units or 10-20% for IV and 3-14% for SFC) it was also found that LMF, MMF and HMF could be used in ice cream, Danish pastry and ice cream coating formulations, respectively.

---

Consumption of foods with low glycemic index (G.I.) by diabetic patients helps maintain their blood sugar at acceptable levels. Ordinary jam has a high G.I. The purpose of the present investigation was to prepare a dietetic jam using nutritive and non-nutritive sweeteners. The investigation was carried out in four steps. First, glycyrrhizin was extracted from licorice extract powder, its ammonium form was prepared, and its purity was assay by HPLC. Secondly, based on a completely randomized design various types of jam were prepared using different combinations of sorbitol, fructose and ammonium glycyrrhizin. Thirdly, the prepared jams and their reference controls were evaluated for color, flavor, texture and overall acceptability by a selected taste-panel and were also subjected to physical analysis using Hunter Lab colorimeter and Bostwick consistometer. Two jam preparations were finally selected on the basis of their overall acceptability. Finally, glycemic indices of the selected jams were determined using NIDDM volunteers. The results showed that ammonium-glycyrrhizin enhances the overall acceptability of the selected product (P<0.05). As G.I. values for the selected jams were low (23.5 and 23.9), their consumption by diabetic patients and their production on a commercial scale are recommended.

---

In order to assess and determine amino acids profile and their availability in different sorghum grain (SG) varieties, three SG varieties including low tannin (0.09% , LTS), medium tannin (0.19%, MTS) and high tannin (0.37%, HTS) were grown at the same location. The grains were analysed for their proximate analyses, tannin and amino acids. True amino acid availability (TAAA) was obtained by Sibbald’s method using ceacectomized single comb leghorn cockerels. The results showed that methionine and cystine were the first and the second limiting amino acids, respectively in LTS and MTS. But in HTS, lysine (0.166%) was the first and methionine (0.176%) was the second limiting amino acid. Methionine content was 0.114% , 0.182% and 0.176% for LTS, MTS and HTS, respectively. Although, crude protein was lower in HTS (10%) than the other SG, but histidine, methionine and isoleucine were higher for HTS in comparison to LTS and MTS. TAAA decreased when tannin content increased and all amino acids had a lower availability in HTS than LTS and MTS (P<0.05). Methionine in HTS and LTS and glutamic acid in MTS had the highest availability. The availability of proline was most affected by tannin, and its availability was 91.55% for LTS, 84.82% for MTS and 22.82% for HTS (P<0.05).

---

Mayonnaise sauce is a nutritious food product with high caloric content, which is usually incorporated into other products as an ingredient. The product should be produced under hygienic conditions to avoid its physical and chemical deterioration along with microbial spoilage, which mostly happens due to the lack of thermal treatment. Mayonnaise is often stored for long periods at room temperature in large plastic containers before consumption. To carry out the investigation, samples of the sauce in large plastic containers and glass jars were obtained directly from a commercial producer. After preliminary quality examinations, they were allocated into 3 lots and stored at 5, 25 or 40^oC for up to 6 months. They were then subjected to physical, chemical, microbiological and organoleptic tests at monthly intervals. The results showed no significant microbial growth even when kept at higher temperatures. Significant chemical changes (autoxidation), however, occurred in both containers at temperatures close to 40^oC. Organoleptic examinations revealed significant changes, especially in color and emulsion stability, which were more evidenced for those stored at higher temperature. It was concluded that the storage of mayonnaise sauce in large plastic containers at higher temperatures should be avoided mostly due to deterioration through physical, chemical and organoleptic changes of the sauce.

---

One of the properties of systemically acquired resistance in plants is their concomitance with the biochemical changes including enhancement of activities of defense-related enzymes. The leaf extract of Reynoutria sachalinensis (F. Schmidt) Nakai is known to be an effective compound for the control of a few plant diseases particularly powdery mildew of cucurbits (caused by fungal pathogen Podosphaera fusca), by inducing host defense responses. In the present investigation, the effects of this extract on some defense responses of cucumber plants were studied via in vivo tests. Changes of defense responses in the extract treated-cucumber plants, with or without pathogen inoculation, were studied and compared with those of non-treated control plants. Results indicated that specific activity of peroxidase increased significantly in treated tissues. Enhancement of enzyme activity showed the same patterns in both the pathogen inoculated- and non-inoculated-plants thus the pathogen attack did not affect the enzyme activity. Specific activity of phenylalanine ammonia-lyase in the non-inoculated extract treated-plants showed a transient fast increase during 24 hours after the treatment, whereas in the inoculated ones, it showed a permanent slow increase probably due to the interaction between extract treatment and pathogen attack. Phenolic content of extract treated-plant tissues, despite small fluctuations, did not show any definite pattern of changes.

---

Chitosan, a deacetylated derivative of chitin, is found in crustacean, arthropod, shell fish and shrimp shell as well as cell walls of some fungi . The objective of this research was to investigate the antimicrobial property of chitosan and possibility of its use as a natural preservative in mayonnaise. In this study, chitosan was produced by chemical method from shrimp shell. The antimicrobial activities of chitosan against Salmonella enteritidis and Lactobacillus plantarum were explored by calculation of the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) in media supplemented with 0.1, 0.2 , 0.3, ..., 0.9 , 1 mg/ml chitosan adjusted to pH 5 or 6 . The MIC and MBC of chitosan differed with pH and bacterial type, ranging from 0.4 to 1 mg/ml. Antibacterial activity of chitosan was inversely affected by pH, with higher activity at lower pH value. The sauce containing 0.1, 0.2 or 0.3% chitosan was inoculated with 10⁶ CFU/gr S. enteritidis or L. plantarum and stored at 5°C and 25°C for 8 days. The inhibitory effect of chitosan concentration was increased from 0.1 to 0.3%. This investigation demonstrated that 0.2% chitosan can be used in mayonnaise as a new preservative.

---

Common kilka were chilled during 1, 2, 3, 4 and 5 days to determine the influence of such storage times of fish over the quality of the final canned product. For this propose, common factors for determination of fish quality (moisture, total lipid, free fatty acid, peroxide, thiobarbituric acid and fatty acid profile) were selected and compared with the formation of fluorescence compounds in fish tissue and filling media of canned kilka. In this work common indices showed higher oxidative and hydrolytic rancidity of canned samples compared to raw material but the trend of deterioration with the increase of chilled storage time was not well shown. However, filling media fluorescence compounds was significantly increased with the increase of chilled storage time and the decrease of fish primary quality (P< 0.05). According to the present results, fluorescence detection of interaction compounds can provide a good technique to assess quality differences in the final product as its relates to the quality of the raw material used.