gh. fadavi

  As bread is the main source of energy and protein in Iranian diet, it is necessary to improve its quality and shelf life. This study was developed to investigate the effect of two hydrocolloid additions on qualities of (Taftoon) dough and bread. Doughs were prepared with different concentrations of gums (0.1 to 0.6% tragacanth and 0.25 to 1.5% guar gums). Farinographic properties of the dough using a farinograph (Model: 827504, Brabender, Germany), physicochemical characterization of the bread, including moisture content, color parameters (L*, a and b) and hardness (during 48h of storage), and the sensory characteristics of the final products were evaluated. The use of different concentrations of tragacanth and guar gums increased the water absorption and valurimetric value of dough samples significantly (P<0.05), and increasing the storage time led to a significant decrease in the moisture content of the breads. Increasing the gum content was negatively related to L* value and positively to the a and b indexes of the bread samples. However, during the storage time, the L* index was significantly reduced. It was shown that an increase in the gum content decreased the hardness index of the breads while increasing the storage time significantly (P<0.05) increased the hardness of the final products. Sensory parameter scores were higher when the gum levels were increased. The sample with 0.3% tragacanth and 0.75% guar gums had the highest dough water absorption as well as the best desirable physicochemical and sensory properties.

In recent years، the scientists have focused on nanotecnology and its applications as the most important fields of research and development. The use of nanoparticles offers many advantages، due to their unique size and physical properties. Magnetic iron oxide nanoparticles have been used in many fields، because of their unique properties such as large specific surface area and convenient separation in magnetic fields. These nano particles have been used for enzyme immobilization، protein purification، and food analysis. This review describes the basic principles and achievements of magnetic iron oxide nanoparticles in enzyme immobilization، protein purification and specifically in food analysis and also their contribution to food sample preparation methods. The presented information shows that magnetic nanoparticles have high potential application in food science and technology.

Pomegranate is an attractive deciduous and somewhat thorny large shrub or small tree (Punica granatum L.) belonging to the family Punicaceae, native to semitropical Asia (Iran) and naturalized in the Mediterranean region in very early times. The edible part of the fruit contains considerable amounts of sugars, Vitamins, Polyphenols, Polysaccharides and Minerals. The physico-chemical properties of 8 Pomegranate varieties (collected from different provinces of Iran) and corresponding juices where investigated. The major minerals index (Mn,Cu,Fe,Zn,Pb,Cd,K,Na,Ca and Mg) were determined by Atomic absorption spectrophotometer. Acidity index was determined by potansiometer, SCC index was determined by refract meter and pH index was determined by pH meter. vitamin C index were determined by titrimetric method and total sugar was determined according to AOAC method. It was perceived by using an atomic absorption spectrophotometer, the quantities of K, Na, Ca and Mg were significantly higher than other minerals (Mn, Cu, Fe, Zn, Pb and Cd) in the fruit juices. In addition the average concentration of Vitamin C, TA, SSC, pH and acidity were respectively 0.25 mg/100g, 13.3g/l, 16.8°B, 3.7 and 0.97. The mineral contents were generally as the same that those established in Iranian national standardthe and codex standard for pomegranate. The study emphasizes that pomegranate fruits can be a good source of nutrients.

Gums play roles such as stabilizers, emulsifiers, texture improvement etc in food systems. Physico - chemical properties of gums determine their applications. In this study, some properties of Zedo gum, which exudes from Amygdalus Scoparia, were investigated. We harvested Zedo gums from the trees in Kerman province and separated into white, yellow and red groups. The gums were tested for protein, fat and ash content according to AOAC. Na, Fe, Mg, Ca, K and Zn were determined by ICP and total carbohydrate by phenol sulfuric method. Thermal analysis was done from 30 to 600 °C. Molecular mass was carried out by size exclusion chromatography and rheological behavior was assayed by a Physica MCR 301 rheometer at 25 °C on 2% (w/w/) dispersions. Zedo gums showed significant difference in some compositions and thermal analysis. All samples contained high molecular weight polysaccharides of above 1million Dalton. An increase in strain caused a reduction in storage and loss moduli. No jell-like behavior was observed among the samples and high temperatures had lowering effect on their viscosities. Zedo gums samples with three colors were investigated. It was demonstrated that some phisico-chemical and rheological differences existed among them. The results showed that Zedo gum and gum Arabic were two quite distinct polysaccharides with different properties.