JWSS - Journal of Water and Soil Science

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This study aims to determine the effects of storage period and egg weight on albumen pH and hatchability of hatching eggs. For this purpose, the eggs produced by native breeder hens (28 - 31 weeks of age) were used in a completely randomized design with a 3 × 8 factorial arrangement. The main factors were 3 egg weight ranges (46 - 49, 50 - 52 and 53 - 56) and 8 storage periods (1, 3, 6, 9, 12, 15, 18 and 21 days). Temperature and relative humidity of storage room was 16 ± 1.5 °C and 75 - 85%, respectively. Storage period had significant effects on albumen pH (P < 0.001), hatchability (P < 0.001), chick weight (P < 0.001), chick weight as a percentage of egg weight (p < 0.01) and late embryonic mortality (15 - 21 days of incubation) (P < 0.05). As the storage period increased from one to twenty-one days, hatchability of fertile eggs decreased from 89.4% to 42.7%, albumen pH, chick weight, chick weight as a percentage of egg weight and late embryonic mortality also increased from 9.25, 34.8 gr, 67.5% and 5.19% to 9.49, 35.9 gr, 70.1% and 42.7%, respectively. Egg weight of hatching eggs also was significantly related to hatchability (P < 0.05), chick weight (P < 0.001), chick weight as a percentage of egg weight (P < 0.01) and late embryonic mortality (P < 0.05). Heavy eggs (53 - 56 gr) had lower hatchability than medium and small weight groups (64.2% Vs. 68 and 69.5%, respectively). As the weight of hatching eggs increased, chick weight (p < 0.001), chick weight as a percentage of egg weight (P < 0.01) and late embryonic mortality (P < 0.05) also increased. The results indicate that, under the conditions of this experiment (16 ± l.5 °C and 75-85% relative humidity), highest hatchability can be obtained with eggs of medium weight range and storage periods of less than three or four days.

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The effects of four levels of SO₂ (0.0%, 0.06%, 0.125% and 0.25%) on the qualitative and quantitative characteristics of two Persian grape cultivars “Keshmeshi seedless” and “Shahroudy” were evaluated during the cold storage in 1995-1997. This research was carried out in a factorial experiment in a completely randomized design in cold storage at the laboratory of Horticultural Department, College of Agriculture, Tehran University.

The results showed that the effect of SO₂ on decay was significant at 1%, and maximum control was obtained at 0.25%. No significant difference was observed when treated with 0.125% SO₂ However, increasing SO₂ concentration resulted in increased quantity and intensity of bleaching on the berries. At these increased concentrations, a linear relation was observed between bleaching on the berries and SO₂ concentration so that the highest bleaching occurred at a concentration of 0.25%. Increased storage periods also increased bleaching. The effect of SO₂ on weight loss, shattering, and rachis colour was also significant, decreasing rachis colour and shattering of berries.

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Physicochemical characteristics of potato (Solanum tuberosum L.) are very important for storage and processing qualities. The amount of reducing sugars (glucose and fructose) and organic acids at harvest, during and after storage is the most important factor. In this study, three potato cultivars (Moran, Marfona and Agria) were collected, dry cleaned and graded into three sizes. They were analyzed for specific gravity and dry matter content. Potato tubers were stored at 4°C and about 85% R. H. for 15 weeks and then reconditioned at room temperature (25±l)°C for 4 weeks. During the storage period of tubers, sugars (sucrose, glucose and fructose) were analyzed on a weekly basis, but citric, D-malic and D-pyroglutamic were analyzed on a monthly basis by high performance liquid chromatography (HPLC). Data were analyzed statistically in a completely randomized design with sampling and Duncans multiple range test.

The total sugar and organic acid contents of tubers significantly increased during the 15 weeks of storage at 4°C and decreased after reconditioning at room temperature. The size of tubers did not affect the accumulation of total sugars. Dry matter content and specific gravity of Agria tubers were higher than those of both Moran and Marfona. Also accumulation of reducing sugars was lower in Agria than in Moran and Morfona initially and after the storage and reconditioning periods. Therefore, Agria must be suitable for processing into chips or dry powder.

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Regarding the importance and high potential of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) for control of the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), the effect of different diets and storage of the parasitoid at low temperatures on its longevity and efficiency was studied. The average longevity of the parasitoid on different diets including honey-syrup 15%, honey-syrup 10%, sucrose syrup 15%, honeydew of whitefly were significantly different at 1% from distilled water and control (without water and food) treatments.

Change in honey-syrup concentration at a range of 5% did not affect the longevity of the parasitoid. The honeydew and sucrose-syrup treatments were not significantly different. This was probably due to the relative similarity of food quality of these two diets. Storage of host parasitized nymphs containing pupae of 1-2 days-old of E. formosa at 8±1°C affected the emergence rate and efficiency of adult parasitoids.

Four treatments including the pupae of parasitoids in 4th nymphal instars of the greenhouse whitefly were stored at 8±1°C for 5, 15, 25 and 35 days. Control treatment included pupae of parasitoid that were held at room temperature, 24±4°C. Host nymphs were parasitized by the parasitoids emerging from all treatments. The average parasitized nymphs by parasitoids emerging from 5, 15 days and control treatments were not significantly different at 1 %.

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Experiments were conducted to evaluate the effects of heat and cold treatments on the disinfestation of dry figs from Estahban. Tow types of packing bags (with or without holes), two storage conditions including one at 23^oC and one cold storage condition (10^oC and 2^oC), 9 heat and cold treatment durations (3, 4, 5, 6, 7, 10, 15, 20 and 25 hrs) and 13 temperature treatments [23, 45, 55, 60, 65, 70, 75, 45+(-25), 50+(-25) and 60+(-25) ^oC] were used in these experiments. The results showed that Indian meal moth, Plodia interpunctella, which is a major pest in dry fig storage, can be satistfactorily controlled by packing figs in plastic bags with a thickness of 0.24 mm after suitable temperature treatment. Cold storage at 2^oC significantly controlled all developmental stages of moths at storage. Temperature treatments at 60^oC for 7hrs or more, at 65^oC for 6hrs or more, and at -25^oC for 15hrs or more were found to be capable of controling pest most satisfactorily without changing fruit external quality.

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In this research, sunflower oil that was extracted and refined at Shiraz Narges Oil Company was packed in four different containers, namely, clear PET (polyethylene terephtalate), yellow PET, yellow HDPE (high density polyethylene), and metal can. Samples were kept at ambient temperature in the shelf exposed to normal light for a period of 1 year. Peroxide values were determined at 45-day intervals and TBA and anisidine values were measured at 0, 6 and 12-month periods. In order to determine the effect of artificial light, some samples in PET and HDPE containers were kept in a wooden box equiped with four (20 w) fluorescent lamps and the peroxide values of the samples were determined. Light transmittance properties of the packaging materials were measured using a spectrophotometer over a wavelength range of 350 nm to 800 nm. The data indicated that the greatest variations in peroxide, TBA and anisidine values were observed in samples in HDPE containers (significantly different at 5% level) kept under normal light and ambient temperature for a period of 1 year. It was also shown that the shelf life of sunflower oil in HDPE container was less than 6 months while for the other packaging materials it was more than one year. Samples exposed to artificial light indicated that the highest peroxide values belonged to samples in clear PET while those in yellow PET proved to have the lowest. Finally, PET container proved to be the most suitable container for sunflower oil followed by metal can. Yellow PET with the lowest transmittance percentage (350-800 nm) and peroxide value (when exposed to 20 w fluorescent lamp) could be substituted for clear PET. HDPE container proved to be unsatisfactory for sunflower oil due to high oxidation rate.

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Three potato cultivars (Solanum tuberosum L.), spring Marfona, autumn Cosima and Marfona, obtained from Isfahan Province, were stored under different conditions: 4^oC, darkness 12^oC, fluorescent light room temperature, darkness and room temperature, daylight. Relative humidity of the above stores was 85 to 90%. Analyses were carried out to determine total glycoalkaloids, α-solanine, specific gravity and total solids, during 30 days for the spring cultivar and 90 days for the autumn cultivars in stored tubers. α -Solanine content of each cultivar was determined by HPLC, in mg per 100 g dry weight, at the beginning, the midinterval, and the end of storage periods. Also, amounts of α-solanine in autumn cultivars, which showed the highest levels after storage for sixty days, were determined before and after heat processing for frying and cooking. Data were analyzed statistically by completely randomized design with Duncan’s multiple range test. The results revealed that the amount of α-solanine of the spring cultivar considerably increased under 12^oC and flourescent light as compared with the other storage conditions. The amounts of α-solanine considerably increased during the storage of autumn cultivars which were stored at 12^oC under flourescent light compared with those stored at room temperature and daylight, room temperature and darkness, and at 4^oC and darkness, respectively. The amount of α-solanine decreased due to spring conditions during the storage period for cultivars stored at room temperature and darkness. In spite of the decreasing effect of peeling, before frying and after cooking, frying and cooking processes had no effect on the amount of α-solanine in the samples. Therefore, according to the above results, the most appropriate storage conditions to prevent increasing effect of α-solanine in potato tubers was 4^oC in darkness.

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Canning of sausage is one of the methods to extend the shelf life of sausage with lower percentage of additives such as nitrite. This method reduces transport and storgae costs, too. The present stduy was carried out in two stages. The first stage consists of preparing sausages with four different formulations in Isfahan Senobar Factory and producing canned sausage. In the second stage, physicochemical and organoleptic experiments were carried out. Canned (214409) and bottled (No. 10-67) sausages were produced and sterilized in autoclave (absolute pressure=2 atm) to give F value = 4 min. Cans and jars were filled with skinless sausage of 22 calibre and brine (2% and 25^oC) at a sausage/brine ratio of 1:1. Chemical composition such as moisture, fat and protein were measured according to the standard and AOAC methods. Physical experimets including measurement of texture shear strength were performed in sausage and canned sausage over the 3-month storage period. Factorial experiments in completely randomized design was used to investigate and analyze statistical data in this study. The Duncan’s multiple range test was used to compare data averages. Moisture content increased and sausgae texture shear strength decreased in all formulations as a result of sterilization. Moisture content increased in four canned sausage formulations while protein and fat decreased (by the end of the second month of storage). Also, sausage texture shear strength was observed at this time to decrease. In organoleptic evaluations, four canned sausage formulations were not significantly different in flavor, texture, and color (P<0.01).

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In this study the effects of four quince harvesting times (at 10 - day intervals), in 2 years on fruit quality during cold storage for 5 months at 0˚C and 85% Relative Humidity were investigated. Fruits were picked from orchards in Flavargan region of Isfahan. Every month, pH, sugar content, acidity, TSS, tissue firmness of fruits were determined. Variance analysis shows that the effect of year on TSS, sugar content, and pectin was siginificant (α =1%) as well as on tissue firmness (α =5%). Harvesting time effect was only significanrt on sugar content while storage time showed a significant effect on TSS, Sugar content and acidity of fruits. Year and harvesting time interaction effect on sugar content and TSS was significant ( α=1%). Year and storage time interaction effect on pH, pectin and tissue firmness was significant while no significant effect on measured parameter was observed for harvesting time and storage time interaction. Simultaneous effect of year, Storage time and harvesting time on pH, pectin and tissue firmness was significant ( α=1%). Meanwhile average analysis by Duncan test showed that different harvesting times had no significant effect on measured parameters except on fruit sugar content. Acidty , pH., and TSS values were changing significantly durig storage. Sugar content of 4th and 5th months of storage was maximum. Pectin content, acidity and tissue firmness showed the maximum level at the first harvesting time while pH was maximum at the 2nd harvesting time. It was concluded that 4th harvesting time (181 days after flowering period) and 5 months of cold storage are the optimum conditions to keep the quality quince.

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Production and consumption of whole tomato and/or its products(tomato paste, tomato juice, ketchup, etc) is incearsed all over the world. Annual production of tomato in Iran is about 3.4 million tons (MT), part of that is processed in the tomato paste factorise, which are mostly located in khorasan province. Since tomato variety has a determinant effect on the physico-chemical and organo leptical properties/quality of tomato and its products, an investigation was performed to evaluate the impact of variety and storage time of four tomato varieties, Cal.j.n.3, Early Urbana Y, Early Urbana 111and Peto early C.H which were selected according to a national project and were monitored according to their brix, pH, Acidity, Sugar and Salt contents, total and non soluble solids. Results indicated that Early Urbana 111 and Peto early C.H contained the highest amounts of soluble solids along with the highest pH. Also it was evidenced that these varieties were the most stable varieties as the least compositional changes was seen in them.

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The Two cultivars of kiwi fruit, Hayward and Abbot, with the desirable quality were harvested on time from Valiabad, a region in Tonekabon (Mazanddaran Provicnce). Fruits were graded and packed in the wooden boxes, cartons and low density polyethylene (LDPE) films, the fruits were cold stored in a proper and constant conditions (T= ±0.5 & RH=90-95%) for a period of 6 months. Samples were taken in completely randomised design from each package for intervals of 30±3 days and during storage (6 months). Chemical characteristics such as the total soluble solids(TSS), titratable acidity as citric acid, dry matter, vitamin C and the Physical characteristics such as yield point (Y.P.), yield point strength (Y.P.S.), penetration force (P.F.) and penetration stress (P.S.) were measured. Statistical analysis was performed with the factorial experiment in an unequal completely randomized design and the means compaired by Duncan multiple range test. The results indicated that, cv, Abbot has shorter shelf life, 4 months, compared to Hayward with 6 months storage period. Hayward contained more dry matter than Abbot throughout the storage period. Total soluble solids of cultivars increased and titrable acidity as citric acid decreased during storage. Vitamin C of Abbot was more than Hayward throughout the storage. Total factors in relation to texture and physical properties decreased by time such texture Hayward cv.after six month storage and in Abbot after four month storage was softer. As the final conclusion, wooden bins packaging for longer storage and plastic packaging for monotonous rippening of kiwifruit was the best in compared with other packaging.

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Qualitative indices including moisture content (M), total lipid (TL), peroxide value (PV), free fatty acid (FFA), heme iron (HI), TBA, neutral lipid (NL) and phospholipid (PL) content were investigated on anchovy fish immediately after harvesting and during frozen storage at -18 and -30°C up to 8 months (2, 4, 6, 8). Profile of their fatty acid and any possible changes were also determined. Statistical analysis of the results showed significant increase of PV, FFA, NL and significant decrease of TL, HT, PL, poly unsaturated fatty acid (PUFA) and omega-3 at each temperature rate in relation to time of storage. Based on the statistical analysis, storing of the sample at -30°C had higher lipids quality. The principal component analysis (PCA) showed that HI can be grouped with important quality indices such as PUFA and omega-3.

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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.

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After construction of a dam across a river, sediments settle behind the dam. It is important for dam designers to estimate the rate and distribution of sediments in the reservoir. In this study, the accuracy of area-increment and area-reduction empirical methods to predict the sediment distribution of Dez, Dorudzan and Shahid Abbaspour reservoirs is evaluated. The last measurement of sediment in these reservoirs was in 2003 (Dez), 2005 (Dorudzan) and 2005 (Shahid Abbaspour). The comparison between actual sediment distribution and predicted sediment distribution by using area-increment and area-reduction methods showed the maximum error at the depth of sediment behind the dam. At higher elevations, the error decreased and reached zero when the elevation was maximum. For Dorudzan reservoir, which has the least sediment volume (31 Mm3), the area-reduction method is less accurate, as compared to the area-increment method (81% vs. 37.5%). For Dez and Shahid Abbaspour reservoirs, where their sediment volume is high (608 and 737 Mm3, respectively), the error of the two methods is relatively equal (in Dez, 29% for both methods, and in Shahid Abbaspour, 22% for area-reduction and 25% for area-increment methods). After long-time sedimentation, the shape factor decreased and reservoir type of all three reservoirs changed to 2.

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At present, soil surface characteristics (SSC) are recognised as key parameters controlling infiltration rates, runoff generation and erosion. Microtopography of surface among SSC is the main one. The work presented in this paper is based on a set of digital elevation models (DEMs) supplied by two different methods: Laser roughness-meter and photogrammetry method. We used two maquettes. The used maquettes correspond to varying roughness (rough and soft roughness). These methods were compared using different statistical parameters of SSC such as heights and slopes histograms. In addition, we studied estimation of Random Roughness (RR) coefficient and Maximum Depression Storage (MDS). RR is considered as an indicator of microtopography and it is one of the main parameters influencing erosion and runoff-infiltration processes. The obtained RR by photogrammetry method showed, on average, 10 percent difference from laser method for soft maquette and 5 percent for the rough maquette. The range of this difference for the MDS varies from 2 to 34 percent, i.e., maximum 0.17 millimetres. In this study, photogrammetric method gives the DEMs with a lower slope for the rough maquette (on average 40.5 versus 46 for the laser method) and higher slope for the soft maquette (about 23.5 versus 20.7 for the laser method). The results showed the DEMs provided by photogrammetric method is able to perform accurate estimation for RR and provides good estimation for the MDS. Therefore, it can be useful in erosion and hydraulic studies.

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Saffron is one of the most important crops in Iran and the quality of its dried stigma is highly depended on the processing and storage conditions. In this study, the effect of different storage conditions in terms of temperature (20, 30 and 40°C) and water activity (0.32, 0.52 and 0.75) during 12 weeks storage on color strength, aroma and bitterness of saffron were investigated. In order to study of moisture (water activity) different saturated solution of MgCl2, Mg(NO3)2, MgBr2 and NaCl in the various temperatures were used. Results showed the color strength decreased as temperature increased. Increasing of water activity resulted in deterioration of crocin and consequently decreasing of color. Furthermore, after 12 weeks of storage, the color strength had a noticeable decrease, the bitterness also decreased but the aroma increased.

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In this study, the effect of “Osmodehydrofrozen” fruit addition on sensory, physical, chemical and microbiological properties of concentrated yoghurt and its quality during storage was evaluated. This research was done in two stages. At the first stage, fruit percentage, type and addition time (before and after fermentation) was determined. The results indicated yoghurts containing 10% apple or 13% strawberry, which was added before fermentation had a better quality. Because of high osmotic activity of apple, the synersis was lower in apple yoghurt in comparison with strawberry yoghurt. According to osmotic activity of both fruits, the synersis value was much lower than that of fruit yoghurts, which contained untreated fruits. Taste value was higher in strawberry yoghurt and texture and mouth feel values were higher at low percentages of fruit. The results of the second stage (quality evaluation during storage) indicated that storage had a significant effect on pH, acidity, synersis, taste and texture (P<0.05). In samples which contained apple, coli forms disappeared after 7 days of storage. In samples that contained strawberry, coli forms disappeared after 7 days of storage.

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The Clark method is one of the most applicable techniques for development of instantaneous unit hydrograph whose efficacy depends upon the accuracy in estimating storage coefficient. The present study was conducted in Kasilian watershed in Mazandaran Province to determine the efficiency of developed hydrograph using Clark's method and to compare the Muskingum storage coefficients obtained through graphical, Clark, Linsley, Mitchell, Johnstone-Cross and Eaton methods. To this aim, the time-area histogram of the study watershed was initially developed. The 3h-unit hydrograph was then derived using the data collected in Sangedeh climatological and Valikbon hydrometric stations. The efficiency of Clark’s instantaneous unit hydrograph developed based on 6 methods for calculation of Muskingum storage coefficient was ultimately compared with the observed average 3h-unit hydrograph of the study area. The results of the study revealed that the Clark’s instantaneous unit hydrograph obtained from graphical method for estimation of storage coefficient with estimation error of less than 33.33% and efficiency coefficient of 83% could suitably simulate different components of the observed average unit hydrograph for the study watershed.

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