نشریه نوآوری در علوم و فناوری غذایی
پیاپی 17 (پاییز 1392)

In This research, it was tried to evaluate the effect of Arabic gel at 0.5%, 1%, 1.5% levels on rheological properties of dough from wheat flour and physicochemical properties including (volume, specific volume, hardness, cooking loss and water activity), staling and sensory properties of Barbary bread. The rheological measurements of the dough were investigated using farinograph instruments. Based on the results of rheological evaluation of dough, adding gel and addition on its levels could lead to a significant increase in the water absorption capacity, dough development time, dough stability in comparison with control sample, while the dough degree of softening after 10 and 20 minutes and Mixing tolerance index significantly decreased in comparison with the control sample, but generally at level 1.5%, a significant decrease on rheological properties of dough was shown in comparison with 1% and 0.5% levels. Based on the results, increase of Arabic gel decreased water activity. Concerning the texture analyzer of bread samples, it was shown that adding Arabic gel and increase in its concentration, significantly reduced staling in comparison with control sample, as bread sample containing 1.5 % and control bread had the least and the most staling rate, respectively. The results pertaining the evaluation properties of bread quality it was shown that adding Arabic gel in level 1.5 % increased volume and specific volume of bread samples. Adding Arabic gel caused a significant decrease in cooking loss of bread samples. Although the 1.5% level led to improvement in rheological properties, the desirable level configuring different aspects of sensory was 0.5% level. So we may choose this level as the best concerning sensory effects in breads.

Mentha spicata is one of the geniuses of Lamiaceae family antimicrobial properties ofextract and essence of this plant on different microbes was tested and approved. The purpose of this study was surveying inhibitory effect of essence for Mentha spicata on the viability of probiotic bacteria in industrial liquid kashk.For this purpose, inhibitory effect of essential oil of Sarsem in two concentrations of 1500 and 2500 ppm on the viability of probiotic bacteria (Lactobacillus reuteri and Bifidobacterium animalis subsp. Lactis) in industrial liquid Kashk was examined during 20 days shelf life in 4°C. The obtained results showed that during the maintenance period and in comparison with control sample, Lactobacillus reuteri in both oil concentration was more sensitive than Bifidobacterium. Inhibition of bacterial growth at 1500 ppm concentration of oil was less than the other concentrations, and most probiotic bacteria survival after the control sample was observed for Bifidobacterium at 1500 ppm concentration of essential oil.

In this study, the oil of 5 olive fruit varieties (Zard, Roghani, Shenghe, Konservolia and Mary) of tarom location were extracted with press and centrifuge methods. Some chemical tests were done on oils which are so important on quality and shelf- life of oil. These tests consisted of fatty acid profile, iodine index, tocopherol and polyphenols. The quantity & quality amounts of tocopherol and polyphenol were determined with HPLC. The profile of fatty acids became distinct with GC method. The obtained results showed that oleic acid, α-tocopherol and, syringic acid, were the main fractions in order of free fatty acid, tocopherol, polyphenol. Significant differences (about a=0.05) were observed in most of chemical characters of olive varieties.

In this study, the effect of malting process on physicochemical characteristics which includes 1000 seed weight, Bulk density, True density, protein amount, rate of ß-glucanase activity and cold water extraction efficiency of two varieties of barely (Sahra and Yusef) in Golestan province have been studied in a completely randomized design with 3 replications and results were analysed by the SAS software. The results analysis of variance showed that type sample on whole physicochemical factors measured in this experiment had a more significant effect (P<0.01). Malting process with 1000 seed weight, Bulk density, True density reduced but protein amount, ß-glucanase activity and cold water extraction efficiency increased. TheMost ßglucanase activity was related to malt obtained from Yusef variety. It was 139.08% more than preliminary barley. Malt obtained from Sahra variety had maximum cold water extraction efficiency (16.4%).

Spirulina platensis is a photosynthetic, filamentous microalgae which belongs to Cyanobacteria. In this study, S.platensis microalgae was added at 0, 0.5, 1 and 1.5% w/w incorporation levels to the commercial formulation of cookies and effects of microalgae addition on protein and iron content, fatty acid profile, textural and color properties of cookies were evaluated by automatic kjeldahl system, atomic absorption spectrophotometer, gass chromatography, texturometer and Hunter lab system, respectively. Results showed that protein, iron and γ-linolenic acid content of fortified cookies significantly increased compared with the control group. Evaluating the firmness changes of treatments showed that the texture of 1/5% w/w microalgae cookies remained well, during storage period (p<0.05). Color stability of 0/5, 1/0 and 1/5% w/w microalgae cookies was significantly more than control along three months of storage period while no significant difference was observed between microalgae cookies (p<0.05). Totally, it can be concluded that it is possible to produce fortified cookies with desirable nutritional and physical characteristics by adding 1.5% w/w S.platensis microalgae.

The best approach to create value added materials from fish processing wastes is protein hydrolyzing by enzymes. In the current research, hydrolysis was carried out using Alcalase at 55°C, PH= 8.5 with 35 Au/kg protein enzyme activity in three times, 10, 20 and 30 min (s), each with three stages using a completely randomized design and three replications. After hydrolysis process enzyme inactivation happened at 90°C for 15min. Soluble proteins separated from the insoluble by 5min. centrifuge at 3000×g. The freeze dried supernatant was used for degree of hydrolysis, protein recovery, peptide chain length and molecular weight determinations. The results showed that in the first stage of hydrolysis for 30min(s). Sample, the highest degree of hydrolysis (8.12%) and the highest protein recovery (27.71 %) was obtained (p<0.05). In the third stage of 10 min. sample, the length of peptide chain reached to its maximum value (48.23%). Molecular weights of the hydrolysates in all samples were under 12.5 KDA.

Application of cress seed gum as a new source of Iranian native food hydrocolloids has been utilized in mayonnaise formulation and chemical, rheological properties and textural attributes of the product has been evaluated. All chemical parameters were in the range of standard mayonnaise characteristics. The results revealed that samples are classified in non Newtonian shear thinning fluids. Viscosity increased with increasing gum concentration and stability observed in all samples produced including different gum levels and no creaming occurred. Hardness increased with increasing gum concentration. According to the obtained results obtained cress seed gum has the ability to be used as a stabilizer in mayonnaise. Since this gum is one of the native hydrocolloids, so it can be a good replacer for synthetic gums in food formulations such as mayonnaise.

In this study, optimization of quality properties of grape during cold storage was investigated by Response Surface Methodology (RSM). Effect of harvesting time in the ranges 5 - 35 days and cold storage time from 0 to 180 days on the flavor index, dextrose, total soluble solute, pH and acidity of Sorkh Fakhri Shahrood cultivar were investigated by Central Composite Design (CCD). Furthermore, the results showed that optimum conditions for harvesting and cold storage time were 18 and 123 days, respectively. At this optimum point, maturity index, dextrose, total soluble solute, pH and acidity were found to be 52.8, 277.06, 16.9, 4.12 and 0.32, respectively. Also, harvesting time after 5 days ripeness was realized as the worst conditions in order to preserve grape during 160 days.

Mayonnaise is one kind of salad dressing used widely all over the world and is highly appreciated because of its texture and flavor. In this study, reduced fat mayonnaise samples (45% oil) were produced using pre-gelatinized corn starch (2-4%), xanthan (0-0.3%) and guar (0-0.3%) as fat replacer by central composite design and their viscosity, stability and sensory properties were analyzed and were compared with those of full fat mayonnaise sample (70% oil) as control experiment. Results showed that the most stability and viscosity values were related to the sample made of 4% pre-gelatinized corn starch, 0.3% xanthan and 0.3% guar and the least values were observed for the sample made of only 2% starch. Sample containing 3% starch, 0.15% xanthan and 0.15% guar (central point) showed the highest score for sensory total acceptability. Most of the samples demonstrated sensory characteristics better than those of the control sample (P<0.05) hence describing high performance of used hydrocolloids. Modeling and satisfactory coefficients of determination revealed goodness of the models to predict data.

The aim of the present study was to survey fatty acids composition and how effective its ’s parameters are on thermal and oxidative stability of soybean (SO), Palmolein (POO) and corn oils (CO) after heat processing. All oils were continuously heated at 180°c for 8 hr.. The evaluated parameters were fatty acids content by G.C, conjugate dienes, anisidine and peroxide value or total polar components. Results showed that POO with 48.66% saturated fatty acids and also with 7.53% poly unsaturated fatty acids, it showed higher thermal stability compared with SO and CO. SO with 7.2% linolenic acid and the highest anisidine value and total polar percent, it indicated heat sensitivity. The changes in the AV value almost for all oils increased during frying time also SO indicated highest Conjugated Diene value compared with other oils.

Mycotoxin contamination in human food and animal feed is a serious problem. In this research, Aflatoxin binding ability to cell wall of Saccharomyces cervisiaie was investigated in order to reduce toxicity in animal feeding. In this study, cottonseed as animal feed was contaminated with Aflatoxin B1at concentrations: 5, 10, 20 μg/lit. The contaminated feed was inoculated with yeast cell culture (heat treated, acid treated and without treatment) in an exponential phase 109 cells/ml) and incubated for 0, 4, 12, 24 hours in order to study AFB1 reduction. Result showed the average reduction of AFB1 for different treatments as follows: acid treatment (3.417 ppb), heat treatment (3.607 ppb) and viable cells (3.96 ppb).Also, the most reduction of toxin was observed within the first four hours of incubation which means that Aflatoxin binding reaches to saturation rapidly. The results indicated that yeast cells, whether viable or non viable are appropriate for detoxification of contaminated animal feeds. Moreover, binding has a physical nature. This property, especially for animal feeding and foods which have high risks of Aflatoxin contamination is considered a pertinent asset.

Fermented dough doughnut is of the most important fermentation products in the world, which is fried after fermentation, dividing, shaping and resting stage. Concerning the recent phenomena of mechanical life and people’s tendency towards fast foods, fried donut has got great attention. Therefore, improving the quantity and quality of this product gets very important. Hence, the aimof this study was to evaluate quantitative and qualitative (moisture, color, hardness, specific volume and overall acceptance) properties of doughnuts made from frozen dough containing Datem Emulsifier and Glycerol mono stearate with three levels of 0, 0/2,0/4% and lipase enzyme in three levels of 0ppm, 100ppm and 200ppm in a completely randomize design. Statistical analysis results showed that humidity increased by increasing the percentage of Emulsifier. Meanwhile, minimum hardness caused the most specific volume and highest total acceptance points in the sample containing 0/2% Datem Emulsifier, 0/2% GSM emulsifier and 100ppm lipase enzyme.