نشریه نوآوری در علوم و فناوری غذایی
پیاپی 5 (پاییز 1389)

This research was done for replacement wheat flour with hull-less barley flour and subsequently phytic acid depletion, an increase in fiber content and bread's nutritional value. Wheat flour with 82% extraction rate was replaced with hull-less barley flour with two different meshes 40 and 50, in 0, 10 and 20% levels. Phytic acid, bonded iron and fiber content in treatments and control were measured and compared. The results showed that replacing wheat flour with hull-less barley flour didn’t affect dough and bread quality. Bread baked from combination of hull-less barley and wheat flour had lower content of phytic acid and bonded iron, and more fiber. Treatment with mesh 50 in 20% level had the most depletion phytic acid (20.3%) and bonded iron (59.44%).

Aflatoxins are among toxic, mutagenic, and carcinogenic secondary metabolites produced primarily by Aspergillus flavus and A.parasiticus. Consumption of aflatoxic foods is associated with several cases of human poisoning, or aflatoxicosis, sometimes resulting in death. Rice is one of the most important crops for human feeding, which is susceptible to aflatoxins contamination. 60 rice samples were collected from 5 states across Mashhad commercial market. The aflatoxin concentration range, was determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The results showed that almost all samples collected contained aflatoxins. AfB1 and AfB2 concentration in rice were found to be 2.55 and 0.34 µg/kg respectively; AfG1 and AfG2 were lower than detection limit. The concentration of AFB1 was more than regulated maximum amount allowed in foodstuffs of Iran in 8.3% of the samples.

The aim of this study was to assess toxic heavy metals concentration including Hg, Cd, Ni, Sn, Zn and Fe in canned tunna fish in iran, winter 2009. The sampling was carried out from three different factories in Shushtar, Chabahar and Esfahan. The heavy metals was extracted from the canned tuna using wet digestion method and concentration of the heavy metals were measured by Atomic Absorption Spectrophotometer Perkin Elmer 4100. Data were analyzed with SPSS17 software in terms of t-test which determined existence or non-existence of the significant difference in level 5 precent (P=0.05). The highest concentration of Hg, Cd, Ni and Sn 48.73±7.55, 336.23±11.08, 171.66±31.21 and 82.20±11.73 µg/Kg was the lowest concentration of Hg, Cd, Ni and Sn 37.53±1.33, 141.43±5.45, 54.99±4.52 and 28.60±1.85 µg/Kg. The highest concentration of Fe and Zn 7.63±0.04 and 5.36±0.82 mg/Kg was the lowest concentration of Fe and Zn 4.29±0.45 and 2.84±0.42 mg/kg.

The Object of this research was Evaluation of biological effect of Saffron(Crocus sativus) extract on stimulation of Enterococcus hirae antimicrobial activity. After the culture of Enterococcus hirae (PTCC 1239) in the BHI broth medium culture, centrifuging and isolation of microbial mass, antimicrobial compound of this strain was purified by dialysis and molecular weight was estimated by SDS-PAGE electrophoresis. Crocus sativus extract was combined with microbial suspension. Total activity, activity unit, Protein concenteration were determined in samples. Antimicrobial effect of these samples were evaluated throuh well diffusion method. Minimum inhibitory concentration of antimicrobial compounds was determined. Antimicrobial effect and inhibitory concentration of Enterocin were evaluated on Staphylococcus aureus and Bacillus cereus and Listeria monocytogenes and Klebsiella pneumonia. The most antimicrobial effect and the least inhibitory concentration produced by Enterocin was on Listeria monocytogenes. Concerning the results gained from this plant, Saffron extract can have synergistic effect on Enterocin production and antimicrobial effect of Enterococcus hirae.

The aim of this study was to compare emulsion properties of D-limonene solution stabilized by whey protein concentrate in three concentrations (10, 15 & 20% w/w) and different homogenization times (3, 6 & 9 min.). Emulsion properties including, polydipersity index, rheological properties and emulsion droplet size were investigated. The results showed that the emulsion droplet size increased significantly with an increase in emulsion concentration from 10% to 20% while increasing the homogenization time from 3 to 9 minutes lowered the emulsions particle size. Rheological properties of emulsions were investigated through Herschel Balkly model. The results indicated that all emulsions had shear thining behavior and emulsion viscosity increased at higher concentrations of whey protein concentrate and homogenization time.

In this study, the effect of emulsions properties stabilized by whey protein concentrate as wall material and d-limonene as core material, on the characteristics of microencapsulated powders were investigated. Colloidal suspensions with concentrations of 10, 15 and 20 % (w/w) whey protein concentrate and d-limonene in water (oil/water emulsion) were prepared. The above suspensions transformed into the emulsion after homogenization for 3, 6 and 9 minutes and then emulsion properties including droplet size and viscosity were measured. The emulsified solutions were encapsulated with spray drying process and consequently the process efficiency, surface oil content and emulsion properties of powdered microcapsules were determined. The results showed that an increase in wall material concentration and decreasing emulsion droplet size could lead to increased efficiency. Also higher concentrations of whey protein concentrate and homogenization time in fresh emulsions resulted in lower variations of droplet sizes between fresh emulsion and redispersed powdered microcapsules.

Traditional butter ghee contains little α-tocopherol and some microbial, enzymatic and metallic contaminations and it is susceptible to decay during production. Hence, for increasing its shelf-life the combinatory antioxidants can be used. In this study, the 0.05%, 0.1% and 0.15% concentrations of Gallic Acid, Quercetin, Citric Acid and BHT antioxidants have been evaluated by Rancimat apparatus at 120 and 150 ˚C. As a result, the selected best antioxidant treatments were preserved at refrigerator (4±1 ˚ C) and ambient (24±1 ˚ C) temperatures for two months. During this period, Rancimat tests, acid value and peroxide number were measured once in two weeks. As a result, at 120 and 150˚ C the best antioxidant was proved to be Gallic Acid with a concentration of 0.15% and during the preservation period, 0.15% Gallic Acid at the ambient temperature was stronger than the other samples and 0.15% Quercetin placed second. The combinatory samples of 0.05% Gallic acid with all levels of Citric Acid showed a significant synergistic effect at 120˚ C.

This study compared the physicochemical properties of three types of major imported black tea available in Mashhad during one year and determined the most appropriate among them for tea consumption (according to the physico chemical properties of them) were performed. Sampling of imported dried tea includes Ceylon Orthodox, Calcutta Orthodox and CTC tea from five different tea packer factory constantly with three samples randomly from each in month according to Iranian standards - tea, Sampling - No. 624 done. Then the samples were transferred to the laboratory to perform all necessary physico chemical tests including moisture, total ash, water soluble ash, ash alkalinity, aqueous extract, crude fiber and caffeine according to Iranian standards - black tea, specifications and test methods - No. 623. Data analysis showed that all three types of tea, among the physicochemical properties only water soluble ash, which indicates the level of soil and contamination of tea was more swings and other characteristics did not have significant change. Overall, all properties except the moisture content of tea was within the standard limit. Also, the results showed that the extent of each of the physicochemical characteristics of the three types of tea varies with one another due to their different origins and production process. On average, among the three types of tea, CTC tea had more desirable physicochemical properties.