JWSS - Journal of Water and Soil Science

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Rice bran is the most important by-product of rice milling. It is a valuable source of edible oil in most rice producing countries. Rice bran oil is used in babyfood, biscuit, poultry, fish and farm animal feeds. The storage of rice bran without 'heat processing will result in hydrolysis and auto-oxidation of lipids, and to its decreased physicochemical, organoleptic and nutritional quality. Rice bran is rich in carbohydrates, free amino acids, lipids and different enzymes. The enzymes have destructive effects on the quality of rice bran components. Heat processing is an effective method to reduce the microbial and enzymatic activity of bran.

This study was carried out using a factorial experiment by completely randomized design with three replications to investigate the effect of heat treatment and storage time on rice bran crude oil properties. The parboiling treatment was effective on the rice kernel strength. The bran produced from parboiled rice milling had lower endosperm components. This type of bran had a lower starch but a higher oil percentage. The results of color of rice bran oil samples determined by Lovibond showed that the oil from parboiled rice bran before and during storage had better color than the other samples. Iodine value of bran oil from parboiled paddy decreased during the storage period. The results from studies on fatty acid composition of oil samples determined by gas chromatography (G.C.) showed that the quantitative trend of fatty acids of the control sample remained the same as that in the rice bran samples with the treatment process.

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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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Iranian flat breads generally have short shelf life. The result of this situation is usually enormous bread wastage. Among the most important factors involved are lack of proper packing and storage methods. In this study, the best temperature for bread packing was determined and the effects of three types of plastic wrapping on Taftoon bread baked of the typical flour were investigated after 72 hours of storage. These wrappings included a two-layer wrapping of oriented polypropylene and polyethylene (OPP/PE) with a thickness of 60 µ, a three-layer wrapping of PP/PE/PE with a thickness of 70 µ, and a two-layer polyethylene with a thickness of 70 µ together with cardboard and plastic. Bread packing was carried out at two different temperature ranges (20-25^oC and 45-50^oC). Results from moisture measurements and water activity test indicated that the characteristics of breads packed in different wrappings showed significant differences (p<0.01). Moisture percentage and water activity (a_w) were lower in layers with higher permeability to moisture and water vapor and, consequently, algal growths reduced in these wrappings. Reduced moisture content, however, reduced the final bread quality score. It was also found that employing cardboard covered in polyethylene had no significant effect on bread shelf life during 72 hours of bread storage. Another finding from the present study was that packing a large number of 10×10 cm bread pieces within one single wrapping with cardboard and plastic was satisfactory and that the presence of the cardboard helped maintain bread shape during transportation and storage.

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In this study, the effects of quality and quantity of protein in flours with 95% and 70% extraction rates obtained from Mahdavi and Tajan wheat cultivars each baked at two different durations (100 and 75 sec.) and temperatures (210 and 250°C), after wrapping in polyethylene packages with 40µm thickness were investigated. All tests were carried out during 168 hours after packing and at 24h intervals. Results indicated that bread staling was affected by wheat cultivar, flour extraction rate, and storage time. Bread prepared from Tajan flour had lower firmness and staleness than that prepared from Mahdavi. High bran content bread was firmer than that with lower bran content. Organoleptic tests indicated that bread baked with 95% flour and bread baked at high temperatures with short durations were not very acceptable.

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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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The Drying process is one of the most important factors which are effective on the milling quality of rice and its economic value. In order to investigate the effect of dryer parameters on milling quality of rice and their relationships, one of the usual rice varieties (Binam) of Gilan province with an average milling quality and the initial moisture content of 20.5% was selected. Drying process was performed on the basis of a complete randomized design with 20 treatments and 3 factors including temprature (at five levels of 30, 40, 50, 60 and 70 °C) , air velocity (at two levels of 0.5 and 2 m/s) and final moisture content of paddy (at two levels of 10.5% and 14% on wet basis equal to 11.7% and 16.3% on dry basis respectively). Results of the experiments indicated that increase of temprature or air velocity reduces drying time but increases drying rate constant (K). It also revealed that decrease of final moisture content of paddy increases drying time significantly, but doesn’t have any significant effect on drying rate constant (K). Correlation test indicated that milling loss (breakage) has a negative relation to drying time and a positive relation to drying rate constant(K), however, bending strength has a positive relation to drying time and a negative relation to constant of K. Regression of qualitative properties of paddy including: milling loss (breakage) and the bending strength over drying time and constant of K revealed that drying time is a better criterion for predicting the mentioned qualitative properties.

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For production of fabricated potato chips, two potato- cultivars namely, Agria and Marfona, were obtained from Daran region of Isfahan Province and stored in cool storage at a proper and constant conditions ( T = 9°C and RH=85% ) . Specific gravity, dry matter and reducing sugars were determined at the time. Potato granule was prepared from both the cultivars by the Add-back procedure. To prepare a sheetable dough, potato granule, corn flour, emulsifier, shortening, water, starch, salt and wheat flour were used. After formulation of a non- adhesive dough, it was sheeted to thickness of mm and formed into slices of 3 cm diameter. These slices were processed by baking, vacuum drying, deep frying and combination of pre-drying and deep frying methods. To select the sample with the best texture a multiple comparison taste panel was held .The best method was baking at 125 for 30 minutes. To improve flavor and acceptability of selected chips, different seasonings (garlic powder, pepper, thyme, lactic acid, onion powder, salt, sugar) were used in chips formula and were compared by multiple comparison and triangle tests. Panelists selected treatments containing salt, pepper and garlic powder as the best formulatins.

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Isotherm curves are useful for the designing of dryer as well as controling of the seed moisture content during storage and drying process. To study the curves, this research was performed on the basis of two factorial experiments including three factors: (1) hybrid at two levels (Three Way Cross 647 and Single Cross 704) (2) temperature at 6 levels (from 5 to 55°C) and (3) Relative Humidity (RH) at 5 levels (from 10 to 90 percent) for the analysis of the adsorption and desorption phenomena. For maintaining RH at the above mentioned ranges, glycerol solutions with different concentrations were used. The results showed that the relationship between solutions concentration and their RH was non-linear and somewhat related to temperature. Also, statistical analysis displayed that for 3 factors of tepmerature , RH and hybrid, the effects on Equilibrium Moisture Content (EMC) in both adsorption and desorption phenomena were significant at α=1%. Comparisons of means showed that hybrid 704 had higher EMC values than did hybrid 647 under the same conditions, in other words, hybrid 704 produced lower a_w than did hybrid 647 at the same moisture content. Fitting experimental values on non-linear models (Henderson, Chung-Pfost and Oswin) showed Oswin as the best model for adsorption and desorption curves for hybrid 704 and also for adsorption curve for hybrid 647 , but the best model for desorption curve for hybrid 647 was Chung-Pfost.

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Bread is widely consumed as a staple food all over the world. The major ingredient of bread is wheat flour which suffers of a couple of shortcomings, such as essential amino acids. To overcome of this problem, a great deal of attention has been made by fortification of bread with different cereal and legume flours. In this study, wheat flour was replaced with 0, 10, 20, 30 and 40% of oat flour to investigate of its effects on dough texture and sensory attributes at room and lower temperatures for 0, 24, 48, 72 h in improved and unimproved breads. Improved formula containing levels of blanched oats, 1.5% fat and 60 ppm ascorbic acid. Addition of oat flour improved bread shelf life. Breads baked with up to 20% oat flour, were considered to be stable along over the time as indicated by sensory evaluation. Samples substituted with 30% and 40% oat flour had the high intensities of bitterness.

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To prepare a sheetable dough, potato granule and potato puree of Agria and Marfona potato-cultivars, corn flour, emulsifier ,shortening, water,starch, salt, garlic and pepper powder were used. Dough was sheeted to thickness of 1-2 mm and formed to desirable shape. These slices were baked at 125^oC for 30 minutes. Prepared potato chips were packed in air or nitrogen atmosphere and stored in dark at 25^oC. Peroxide value, bending strength and color of the samples were determined in 30 day intervals. Peroxide value was detected just at the end of the third month. Peroxide value in chips packed in nitrogen atmosphere was less than that in chips packed in air atmosphere. Atmosphere of packages had a significant effect on the bending strength of the chips (p<0.01). The bending strength of chips packed in nitrogen atmosphere was more than that of chips packed in air atmosphere. Storage time had significant effect on bending strength (p<0.01). Storage time and cultivar effects on lightness and darkness of chips (L in hunter lab system) were significant (p<0.01). Storage time and cultivar effects on yellowness and blueness (b) of chips were significant (p<0.05). Storage time, cultivar and packaging atmosphere had no significant effect on redness and greenness (a) of chips (p<0.05)

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Lots of investigation has been done in order to increase wheat yield per acre in Iran, but there is not enough study about quality of produced wheat. Bread quality in Iran has been deteriorated in recent years, mostly due to employing wheat flours of low quality. Thus the present study was conducted to find the chemical and rheological properties of four bread wheat cultivars (Omid, Rosshan, Golestani and “Kal”) produced in Sabzavar region. The results indicated that the quantity and quality of “Kal” wheat gluten are more desirable in comparison to the other varieties. The rheological experiment results indicated that the Omid wheat flour is the best regarding the dough resistance coefficient and alfa amylase activity. The alfa amylase activity of all flours was low. Appropriate time for fermentation of bread dough for all flours was 75 to 90 minutes. Mixture of one to ten ratio of Roshan and Omid flour produced bread with better quality. The results also indicated that the rheological properties of “Kal” flour dough such as mixing resistance, breaking point resistance and valorimeter value are acceptable. The bakery properties of “Kal” flour is better than Rosham flour. The “Kal” variety of wheat is the same as Roshan variety and the only difference between them is the region of production and farming conditions. It shows that farming condition is one of the important factors affecting bread wheat quality.

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Homogenized milks at 0.5 and 2.5% fat content were each fortified with three levels of Vitamin A palmitate at 3000, 4000 and 5000 IU/L. Vitamin was added just before homogenization and then pasteurized milks were packed in polymeric pouches and glass bottles. All samples were refrigerated at 4-5 °C for 48 hours. Any reduction in vitamin A level was monitored using HPLC, while sensory evaluation was conducted in order to rank the samples. ANOVA and Friedman analyses indicated that fat content along with package type had a significant effect on the residue of vitamin A. The loss of vitamin A was significantly higher in 0.5% milk either packed in polymeric pouch or glass bottle. However, besides fat concentration, more vitamin A was lost in glass bottles rather than polymeric pouches. Sensory evaluation showed that milk fortification had no adverse effects on color and flavor of the product.