IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2010 | Volume:7 | Issue:3|Papers Count:16

In order to study the effects of different nutrition systems (organic, chemical, integrated) and plant growth promoting rhizobacteria (PGPR) on on the grain yield, seed oil content and fatty acid composition in Sunflower (Helianthus annuus L. cv. Alestar) an experiment was conducted using Alestar cultivar at the research farm of college of agriculture, Tarbiat modares university of in 2007. Five levels of nutrition systems including F1 (100% organic), F2 (75% organic+25% chemical), F3 (50% organic+50% chemical), F4 (25% organic+75% chemicaL), F5 (100% chemical) in main plot and two levels of biofertilizer I1 (inoculation) and I0 (control) as subplot were used in a split plot arranged in a randomized complete block design with three replications. Results showed that the integrated fertilizer system had higher grain yield than the other fertilizer systems (F3›F4›F2›F5›F1). Maximum and minimum oil content were obtained with the F3 treatment and F1 respectively. The oil saturated fatty acids (acid palmitic and acid stearic) decreased significantly, while insaturated fatty acids (linoleic acid and oleic acid) increased significantly in response to raising the FYM-rate. The highest linolenic acid and oleic acid were observed in F3 and F1 treatments respectively. The results revealed that PGPR improved plant productivity and quality in sunflower seed. The inoculation of PGPR (I1) increased, grain yield, oil content and unsaturated fatty acids and decreased saturated fatty acids compared with untreated plants I0.

In order to produce high quality pasta, semolina; the durum wheat flour, is generally used. However, semolina is not available for every pasta factories in Iran. Hence, many of these factories use bread wheat flour (farina) to produce pasta. Consequently, the pasta may be of low quality and not suitable for export. The objectives of this study is to improve the quality of dough and the resultant spaghetti produced from farina using 0.5% (w/w, flour basis) hydroxypropyl cellulose (HPC). After preparation of dough with moisture content of 31.5%, the rheological properties of the dough were tested using Brabender Farinograph. The results showed that addition of HPC increased the dough development and stability times. The results of creep test (using Texture Analyser) revealed that addition of HPC increased the elasticity of the dough while its viscosity decreased. The results of cooking tests in distilled and salted water (2% w/w) showed that the HPC sample had longer optimum cooking time. Moreover, the HPC sample had higher water absorption and lower cooking loss than the control. Addition of HPC could improve the texture of the cooked spaghetti. Addition of salt to the cooking water increased both water absorption and cooking loss of the samples.

Fish skin gelatin could be substitutes for mammalian gelatins. But fish gelatins have low gelling and melting temperatures. In this research improvement of functional properties of lizard fish skin gelatin (melting point, gelling point and bloom) evaluated by mgso4 (0.1 and 0.5 M), glycerol (15%), NH4NO3 (5%), Katira (0.5 and 1.2%) and sucrose in three pH (4, 5, 6). All materials have significant different (p<0.05) to the control. Based on results glycerol, katira (0.5%) and sucrose have maximum effect on improvement of functional properties and pH 6>5>4 had enhancer effects on the variables .This improvement of gel properties is due to the fact that this materials stabilizes hydrogen bonding and in higher pH the gelatin pH is closer to the Isoelecteric point of the protein. Katira is a natural material and due to minimum usage, has the best effect. Results of this research registered in the Iran Invention Office (number 48947).

In this study, lactic fermentation was used in order to improve the quality of loaf bread (baggett). Lactobacillus plantarium was cultivated in a medium composed of wheat flour and water and added in bread dough formulation at 0, 5, 10 and 15% concentrations. After baking, Staling, physicochemical (pH and acidity) and organoleptic properties (crust characteristics, taste and odor) were evaluated. Results showed that bread acidity as the concentration of sourdough increased in dough formulation. Acidity and pH of sample bread that contained 15% sourdough was 6.5 and 4.87 respectively. Also, in this sample staling and quality changes during storage were at least. Highest score of taste were belonged to sample contained 5% sourdough. Sample contained 15% sourdough gained highest score of odor and crust properties.

The influence of different levels of NaFeEDTA compound on the physicochemical and sensory properties of Petit Beurre biscuit was evaluated. NaFeEDTA was added to biscuit formulation in levels of 576, 720, 864, 1008 and 1152 mg/kg so that 100 gram of fortified biscuits to be contained 7.2, 9, 10.8, 12.6 and 14.4 mg iron/100 g respectively. Fortified biscuits were stored in polyethylene pouches for 60 days under ambient temperature condition (17-20oC) and far from light. Fortification with NaFeEDTA had not significant effect on pH, moisture and ash content of fortified comparing to the control. The data measured an Atomic Absorption instrument showed that iron content was significantly different between the fortified and control samples (P<0.05). The percent of iron loss for fortified samples ranged between 2.63%, 0.33%, 0.64%, 2.53% and 1.18% respectively. The peroxide value was increased in all samples during a 60-day storage period; however this increase was higher in the fortified biscuits as compared to control especially after 28 days. NaFeEDTA compound at different levels had not significant effect on breaking strength of fortified biscuits. Sensory evaluations were showed that the addition of NaFeEDTA to the biscuit formula have significant effect (P<0.05) on the color, texture, and flavor of fortified biscuits. With regard to the results and also the use of NaFeEDTA in the proposed fortification range (10 mg iron, 67 mg EDTA/person per day), 720 mg/kg (9 mg iron/100 g) level of NaFeEDTA as an optimum level for biscuit fortification was suggested.

Sodium diacetate is a safe chemical presevative which is used as an inhibitor against mould, yeast and some bacteria. In this study anti-microbial effect of sodium diacetate on preventing the growth of some spoilage microorganisms in carbonated beverages was investigated by broth diulation suceptibility test in medium. At the concentrations of 101, 102, 103 and 105 cells of Saccharomycess cerevisiae per ml 156, 313, 1250 and 5000 ppm of sodium diacetate were respectively determined as the minimum inhibitory concentrations (MIC) preventing growth of the yeast. As for Candida krusei, 625, 1250, 2500 and 5000 ppm of sodium diacetate were MIC inhibiting the growth of the yeast at concentrations of respectively 101, 102, 103 and 105 cells/ml. 2500 and 5000 ppm of sodium diacetate were determined as MIC inhibiting the growth of Leuconostac mesenteroides at the concentrations of respectively 102, 104 bacteria/ml, and for 102 bacteria/ml of Lactobacillus delbrukii was prevented by adding 2500 ppm sodium diacetate. No inhibitory effects of different concentrations of sodium diacetate observed at none of the prepared spore suspension of Aspergilus niger, so no concentrations of sodium diacetate were determined as MIC for this species of mould.The results show that sodium diacetate has inhibitory effects on the above selected yeast and bacteria but no inhibitory effects on the mould of Aspergilus niger.

Sugar-beet pulp, one of the byproducts of sugar industries, contains several important components such as pectin, cellulose and hemicellulose. In this study, firstly cellulose was extracted from sugar-beet pulp. The extracted cellulose was then converted to carboxymethyl cellulose (CMC) by an etherification process preformed at 70oC. Degree of substitution, purity and moisture content of the CMC were, 0.52, 53% and 7%, respectively. The properties of the produced CMC was compared with other thickeners (i e. commercial CMC (Merck), tragacanth gum and a formulated commercial gum (available in the market). All four hydrocolloids were used in the formulation of tomato ketchup at 1% level. The chemical composition, rheological properties, syneresis and sensory evaluation tests were performed. There was no significant difference between the samples in terms of chemical composition. The viscosity of the ketchup samples with beet pulp CMC was much greater than the control without gum, but lower than the samples containing other gums. A slight syneresis was also seen in the samples with beet pulp CMC after one month of storage. Sensory scores of the samples with beet pulp CMC was greater than other samples. Overall, in despite of low purity and DS of the produced CMC, beet pulp CMC has a good potential to be used in food products as a thickener.

Salting-drying carp is a fish products traditionally consumed in Iran. So, a study was conducted to obtain a better understanding of various physicochemical contents, bacterial and sensory properties salting-drying carp. Samples of fillet and gutted carp were salted at 4oC for 10 days, which was followed by sun drying and storage. The results obtained showed that protein and moisture contents decreased during different stages processing (p<0.05). The loss of moisture was accompanied by an increase in salt. The fat content remained constant during different stages of processing. The pH of raw fish decreased (p<0.05) from 6.86±0.10 to 5.32±0.32 and 5.65±0.41 in fillet and gutted carp respectively during pickled salting and then increased (p<0/05) during the later stages. TVBN decreased after pickle salting and then increased in sun drying and storage stages (p<0.05). The TBA content of raw carp increased during all stages of processing (p<0.05). In gutted samples of salting the protein, moisture, pH, TVBN and TBA contents except salt was more than in fillets. Organoleptic properties in fillet and gutted carp except in taste gutted fish were similar during different stages of processing (p>0.05). Mesophilic and halophile bacterial counts increased significantly during process, but psychrophilic bacteria counts decreased during different stages of processing (p<0.05).

Now adays around the world, raisin concentrate is considered as a valuable material for producing nectars, raisin paste, raisin juice and confectionary industries as well as a natural alternative for sugar, there are numerous raisin production which condensed concentrate is of great importance It has variable properties and industrial utilizations. In order to extract it, tests were conducted in three levels of extraction temperatures (40oC, 60oC, 80oC), These levels of solvent proportion (1:1, 2:1 and 3:1) and three levels of condensation temperature (65oC, 75oC, 85oC). At the end the chemo- physical characteristics (color, viscosity, and freed sugar concentrate weight and production efficiency) were studied carefully, and then microbial tasts (mould, fermentation and total counting) were carried on. After the statistical analysis, those extracted at the extraction temperature 80centigrade degrees and 75 centigrade degrees condensation temperature, and solvent proportion 2:1, 3:1 leading to better result are suggested, considering higher extracted as well as condensation in thermul conditions.

In this research the production of tomato juice concentrate in the fruit nectar production plant and using existing equipments have been studied. Tomato juice was produced and then concentrated under high vacuum condition at temperature lower than 50oC up to 20.25 Brix in the laboratory scale. In order to study the quality specifications of the tomato concentrate and juice, the concentrated juice was recombined and physical and organoleptical tests including color, appearance, consistency and flavor were performed. The samples kept for one and three months at temperatures 4, 25 and 35oC were studied. Results showed that fruit nectar production line has significant effects on color and vitamin C content of tomato juice. However with additional equipments it is possible to produce a high quality tomato juice concentrate. Moreover it was found that the concentration of tomato juice, had no significant effect on the quality of recombined product and 97% of vitamin C content was remained unchanged.

A laboratory dryer used for a thin layer of  165 g Thompson orange slices with three thickness levels of 2, 4 and 6 mm, five different temperatures of  40, 50, 60, 70 and 80oC and three air speed levels of 0.5, 1 and 2 m/s were employed to find the best dried and minimum energy consumption. This experiment was done in a complete randomized block design with the factorial treatments performed in three replicates. The energy consumption for drying thin slices of orange was calculated accordingly. The analysis of results showed that the lowest and highest drying energy consumption were 3.35 kWh (for 2 mm slice thickness and 40oC) and 15.2 kWh (for 6 mm slice thickness and 70oC), respectively.

Emulsan compound produced by Acinetobacter calcoaceticus RAG-1 ATCC-31012. At present, this bioemulsifier show potential applications many sectors of food industry (soft cheese and ice creams). The ability of a bacterial to grow and produce emulsan by response surface methodology under shaking incubator conditions at 30oC was studied. Crude oil and ammonium sulfate at different levels use as a carbon and nitrogen source respectively. The medium culture optimum for emulsan production was occurred 4% (v/v) carbon source, 3 gr/lit ammonium sulfate and 7% (v/v) inoculum’s size. At optimum levels of these parameters, 2.9 gr/lit biomass at end of fermentation was obtained. Production of emulsan by this bacterial culture resulted in surface tension reduction to 30 mN/m. Coefficients of determination, R2, of fitted regression models for biomass production and surface tension are equal to 97.13% and 95.52%, respectively.

Mayonnaise as an oil in water emulsion with pH<4.1 is one of the oldest man-made emulsions that one of the most widely used sauces in Iran and in the world. Nowadays, gums are widely used to increase stability and also changing the rheological properties of mayonnaise. Gum tragacanth as a plant exudation is an Iranian native gum that it indicates a high viscosity in acidic conditions. Though, it is proved that the gum obtained from different species of Astragalus have an absolutely different physico-chemical properties. So far no comprehensive research has ever been done on the effect of different species of gum tragacanth on the rheological properties of mayonnaise sauce. In this research it was attempted to study the effect of gum tragacanth obtained from two different species of Astragalus gossypinus or Ag and Astragalus rahensis or Ar on the flow and oscillatory rheological properties of mayonnaise and was determined the effect of gum concentration and temperature on the mentioned properties. Finally, it was compared with the commercial sauce prepared by using imported gums.The mixture was stirred for 11 min by a rotary mixer at 1000 Rpm. pH and stability tests were done. A comparison of microstructure of the mayonnaise sauce produced with different concentrations of two species of Gum tragacanth was conducted with a light microscopy equipped by a camera. Steady flow and viscoelastic properties were determined by using a controlled shear rate Rhometer.It was shown that all treatments (type of gum and its concentration) had significant on oscillatory rheological properties. After determining the Herschel Bulklley model to describe experimental data's steady rheological tests it was shown that the mentioned rheological factors had a significant on some of these parameters and apparent viscosity of mayonnaise sauce. A comparison of prepared mayonnaise sauce with two species of Gum tragacanth in different conditions with commercial mayonnaise sauce showed that all factors in every specific level just can make close some characteristic of produced mayonnaise to commercial sample. So the study about the effect of using mixture of different species of Gum Tragacanth with each other or with the other gums on quality of mayonnaise sauce is suggested.