IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2017 | Volume:13 | Issue:59|Papers Count:21

Bread is the major food for a lot of peaple in the world and breadmaking is too long and needs skill. Also, Bread is a food product with short shelf life so for eliminating these problems released frozen bakery products. The freezing of bread dough, despite of its advantages has some disadvantages like decreasing of bread volume, expediting staling and destruction of product finl texture. The purpose of this research is to investigate the effect of Sodium Stearoyel 2-Lactilat emulsifier (SSL) and whey protein concentrate (WPC) for improving quality and staling of the bread from frozen dough. Therefore, SSL was used at 0, 0.4, 0.8% and WPC at 0, 3.75, 7.5% levels using central composite design. Dough samples were stored at -18oC for 1 month and the effect of adding the mentioned substances on bagguette bread quality properties was investigated. The results of tuxture profile analysis showed significant effect in the level of 1% about the amount of force applied on bread (P<0.01). Also the results indicated significant effect on increasing spesific volume (P<0.01) and overall admission on sensory evaluation of the bread (P<0.05). In this research, %0.5 SSL and %3.8 WPC was selected as the best treatment after optimizing results by response surface methology.

Necessity of frozen dough products mostly bread is a daily need of most communities due to its energetic role and being the main meal. The freezing of bread dough, despite of its advantages has some disadvantages like gradual decreasing of dough resistance. The purpose of this research is to investigate the effect of Sodium Stearoyel 2-Lactilat emulsifier (SSL) and whey protein concentrate (WPC) for improving quality of dough and frozen dough structure. Therefore, SSL was used at 0, 0.4, 0.8% and WPC at 0, 3.75, 7.5 % levels using central composite design. At first, the effect of adding these two substances as independent variables on dough rheological properties was investigated by using farinograph .Then dough samples were stored at -18oC for 1 month and the effect of adding the mentioned substances as independent variables on structure of frozen dough was examined by electron microscoy. Farinograph results showed that adding SSL and WPC had significant effect on water absorption of flour and caused significant increase on the dough development time, dough resistance and valorimetric value. These results also revealed significant decrease of dough softening degree (P<0.01). The pictures obtained by electron microscopy showed that adding these two substances improved structure of frozen dough. In this research, %0.5 SSL and %3.8 WPC was selected as the best treatment after optimizing results by response surface methology.

Fermentation is used for centuries to protect quality improvements or flavor modifications of cereals, fruits, vegetables, milk and meat. Yellow Zabol kashk (Sistani) is a grain-dairy fermented product, which is highly consumed in Sistan-Baluchistan province. The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product to introduce the native strains. These strains could be used in industry or some of them may be considered as probiotic strains. The cell morphology of each strain was investigated. Then gram-positive and catalase-negative isolates were selected. In order to classify 83 selected isolates that seemed Lactic Acid Bacteria according to preliminary experiments, physiological and biochemical tests, including growth at 10oC and 45oC, 6.5% NaCl, pH=4.4 and pH=9.6, carbon dioxide production from Glucose and carbohydrates fermentation were performed. Twenty eight selected isolate identified genotypically based on 16S rRNA gene sequencing. The results showed that the isolates belong to: Lactobacillus plantarum (24.09%), Lactobacillus helveticus (13.25%), Lactobacillus brevis (963%), Lactobacillus delbrueckii (18.07%), Lactococcus lactis (13.25%), Leuconostoc mesenteroides (9.63%), Leuconostoc citreum (2.40%) and Pediococcus pentosaceus (9.63%). To identify the bacteria, especially lactic acid bacteria it is suggested using both culture and molecular-based method.

Tuluq and Torba bag yoghurt are the traditional concentrated yoghurt that is produced in some parts of Iran such as Azerbaijan. In this study, traditional concentrated yoghurt was produced in four methods, Tuluq and Torba bags, packed in polyethylene containers and was evaluated with control yoghurt during storage time. The chemical properties were included pH, acidity, total solid, fat and protein content. Also samples were evaluated of the Starter cultures such as Streptococcus salivarius ssp. Thermophilus, Lactobacillus delbrueckii ssp. Bulgaricus count, post contamination microbes such as coliform, psychrotrophic bacteria, mold and yeast count and pathogenic microbes such as Staphylococcus aureus and E. coli count. In analysied samples yoghurt, pH were (3.89-4.56), acidity (0.94-1.70 g/100 g), total solid (12.5-37.5%), fat (2.9-17.9%) and protein content (3.7-12.5%). Starter cultures decreased during storage time. Streptococcus Thermophilus count was more than Lactobacillus Bulgaricus count during storage time. Psychrotrophic bacteria mold and yeast count increased during storage time but the coliform, staphylococcus aureus and E. coli bacteria did not change. The results revealed that Tuluq yoghurt not only has high nutritional quality and microbiological properties but also has long shelf-life and it can be introduced as a valuable dairy product.

Wild medlar fruit (Mespilus germanica) is rich in sugars and organic acids. In this study, wild medlar concentrates in four concentrations of 14, 28, 42 and 56% (oBrix), preparation and physicochemical properties including pH, acidity, density and color, and rheological properties (at 20, 30, 40, 50, 60 and 70oC) were studied. The pH was in the range from 3.37 to 3.62 and acidity according to citric acid was in the range of 1.05 to 3.90%. Density of concentrated sample (56%) was 1277 kg/m3. Color of samples was analyzed using image processing technique and image parameters including L*, a* and b* for the sample with a concentration of 56% was 20.54, 1.69 and 1.36, respectively. With increasing in concentration, the sample was darker and L* index decreased. Concentrate used in all concentrations showed Newtonian behavior and viscosity increases with increasing concentration. With increasing in temperature from 20 to 70oC, the viscosity of the concentrate (56%), decreased from 2517 to 223 mPa.s. The magnitude of activation energy was found in the range of 9.59-43.39 kJ/mol K.

Application of microbial lipids as an alternative source of oil was considered in the early years of 20th century. Microbial oil rich in essential polyunsaturated fatty acids (omega series) is one of the important aspects of single cell oil production. By development of technical - economical processes and also by optimization of microbial lipid production, high efficiency of microbial lipid can be provided. In this study, two standard yeast strains and four native strains were evaluated for potential of lipid production. Optimization of lipid production in these strains was carried out using design of experiments and factors affecting lipid synthesis in these strains were compared. Obtained oil was analyzed using Gas Chromatography-Mass spectrometry (GC-MS). Among the standard strains, Yarrowia lipolytica DSM8218 and the native strain Cryptococcus albidus had maximum lipid production rate of 7.65 g/L and 11.81 g/L, respectively. Application of Taguchi method was so effective in optimization of microbial lipid production and significantly increased production in evaluated strains. These lipids have potential for applications in food and pharmaceutical industries.

Application of additives is one of the proper solutions in quality enhancement in bakery products such as gluten matrix promotion, softness and unity of the texture and delay in staling which are effectives on shelf life and marketability of the bread. So the aim of this study was to investigate the synergistic effect of Datem, SSL and E471 as an emulsifier in level of 0.2% and 0.5% humectants such as polypropylene, glycerin and polysorbat 60 in compare to the control (without additives) on quantitative and qualitative properties of semi bulk Barbary bread. Image processing and Image J software were used for evaluation porosity and color values of samples. The results showed that the addition of a combination of emulsifiers and Humectants improved the specific volume, porosity, overall acceptability score and color values of samples in compare to the control. while the firmness of bread was reduced significantly (p<0.05). The results indicate SSL had the better performance that E471 and polypropylene was more effective in compare to the glycerin and polysorbat 60. Finally, the results indicate that the synergistic effect of 0.2% Datem and SSL with 0.5% polypropylene as humectants was more than others. So that leads to the excellent and marketable product.

By irradiation as Food processing method, Food quality is maintained and control of microorganism causes prevention of corruption. Simultaneously, Methods of drying, which leads to maintaining the quality and texture, are used. In this study, optimal conditions were determined by drying gamma rays irradiated potatoes with response surface method. For sample, the source of 60 Co irradiation (Gamma Cell 220) was used. Samples with 0, 2, 5 and 8 kGy doses were irradiated. Drying using microwave power at 200, 400 and 600 W and in three thicknesses of 5, 7 and 9 mm of sample was performed. Optimal conditions for radiation dose of 5 kGy, sample thickness of 7 mm and a microwave power of 400 W and L*, a*, b*, color changing, hue angle, Croma and browning index were proposed to 57.87, -0.95, 42.19, 10.73, -1.53, 42.22 and 113.59, respectively. In addition to the effects of radiation variables, the thickness of the sample and the microwave drying effect on indicators such as L*, a*, b*, browning index, Croma and hue angle was investigated. With increasing irradiation dose, increasing the thickness of the sample and the microwave power, the color index decrease, Hue angle color and color density increases and decrease, respectively. Finally, using the neural network model, drying of irradiated potato was modeling and ability of the model to predict of the color changes in regression and response surface method was compared. In this comparison the neural network model was capable for prediction higher than the regression model (R2=0.9706).

In this research, time dependency of low fat- low cholesterol mayonnaise with 35 and 50% oil at the different concentration of Lepidium perfoliatum seed gum (0.5, 0.75 and 1%) and whey protein concentrate were studied. Data were fitted with famous rheological models. Results showed that all samples had thixotropic behavior and their viscosity decreased with time. The rate and extent of viscosity decay were dependent on the applied shear rate, percent of fat and gum concentration. The viscosity of the samples tended to decay more rapidly at higher shear rates toward an equilibrium viscosity. Samples containing less fat, showed lower viscosity and approached rapidly to the equilibrium. Addition of gum to mayonnaise caused higher viscosity and samples become like the full-fat sample. In this study, the breakdown rate constant did not show a clear trend with increasing gum concentration and shear rate.

In order to optimize the utilization of the advantages of packaging in the food industry, it is necessary to identify the most effective components and criteria in the packaging of food products field and to prioritize these products based on the opinions of consumers, so that the results can be considered in the planning and marketing activities of organizations. Regarding such importance, the aim is that this research evaluates the impact of those identified attitudes which shape an attitude on Packaging on customer Satisfaction and Involvement. Based on data collection, the present study is considered as descriptive. Before collecting the data through questionnaire, and so as to check the validity and reliability of the study, a pre-test was taken. Moreover, to assess the validity of the study, the diagnostic validity (DV) using an average variance extracted (AVE) was first calculated and the composite reliability (CR) was then applied to determine the reliability. Therefore, first the researchers reviewed the research literature, then, statistical sample of the population who were the customers of Shadlee in Tehran, were selected and the research hypotheses were tested using structural equations and regressions. Research findings show the significant impact of such Dimensions as “color”, “Attraction”, “Shape”, “Information on the Package”, “Size”, “Type of material” and “Health issues”, on “attitude toward Packaging” and the significant impact of “attitude toward Packaging” on “Customer Satisfaction” and “Involvement”.

Celiac is life-long intolerance to the glidin fraction of wheat and the prolamins of rye (secalins), barley (hordeins) and possibly oats (avidins). The most challenging products to formulate and produce are gluten- free bread and pasta, as gluten is their structure-building protein. The purpose of this research was to evaluate effect of Hydroxy Propyl Methyl Cellulose (HPMC) gum and Microbial Transglutaminase (MTGase) enzyme on farinograph properties of dough and quality characteristics of pasta. For this purpose HPMC at three levels (1%, 1.5%, 2%) and MTGase at three levels (0.3%, 0.5%, 0.7 %) were added to formulation. Results showed that addition of HPMC and MTGase increased dough development time, decreased degree of dough softening, cooking loss and stickiness of pasta. In addition HPMC increased dough stability time, water absorbtion and moisture of pasta. While MTGase had no significant effect on this parameters. Also the colour test analysis results showed that addition of HPMC and MTGase had no significant effect on the colour of pasta. Finally results of sensory evaluation showed that pasta containing 2% HPMC and 0.7% MTGase had high mean score for texture and overall acceptability compared to control.

To investigate the effect of edible coatings in retarding of bagutte bread staling, three types of coating formulations containing Sodium alginate, carboxymethyl cellulose and xanthan as hydrocolloids and sunflower oil, glycerol, water, starch and potassium sorbate were used for coating of baguette bread and The effect of these coatings on retarding of staling after 1, 2 and 3 days of storage was investigated. The obtained results revealed that after 1 day of storage the mentioned coatings presented bread with similar freshness to that of control [fresh sample]. After 2 days of storage, sodium alginate and xanthan coated samples acted similar in retarding of staling and after 3 days of storage, all the coatings did not have any significant difference with each other and also with control sample from staling point of view.

Firmness is a very important quality property for kiwifruit. This property is affected by storage temperature and duration. Recently, some destructive and non-destructive methods were developed and used for fruit firmness assessment. However, non-destructive methods have merits of real-time and online applications as well as preventing fruit destruction. The objective of the present study was to evaluation of non-destructive acoustic technique for assessing the kiwifruit firmness at two different temperature levels during a storage period. On this basis, firmness of kiwifruit during two weeks of storage by non-destructive method was monitored. For determining the correlation between resonant frequency, stiffness and elasticity coefficients, and fruit firmness, destructive puncture test (Magness- Taylor) was also applied. The maximum penetration force in puncture test depicted a strong correlation with those from acoustic tests, resonant frequency, stiffness coefficient and elasticity modulus with the coefficients of determination of 0.838, 0.857 and 0.865, receptivity. According to the maximum correlation coefficient between modulus of elasticity and firmness, the relation was verified by new set of data, and revealed that it could estimate the fruits firmness with an error of 7.4 percent. Therefore, nondestructive acoustic test is an appropriate substitution method for estimation of kiwifruit firmness during shelf-life.

In this study, the combination of infrared - hot air dryer was used for drying of button mushroom. The effect of infrared lamp power (150, 250 and 375 W), hot air temperature (50, 60 and 70oC) and hot air rate (1, 2 and 3 m/s) on drying of button mushroom were investigated. The results of infrared-hot air drying of button mushrooms showed that by increasing of lamp power from 150 to 375, the drying rate increased. With the increase in hot air temperature from 50 to 70oC, and hot air rate from 1and 3 m/s, weight loss increased 10.3% and 13.9%, respectively. Also process modeling were done with the genetic algorithm–artificial neural network (GA-ANN) method with 4 inputs (lamp power, hot air temperature and rate, drying time) and 1 outputs for prediction of weight loss. Sensitivity analysis results by optimum GA-ANN showed the drying time of mushroom was the most sensitive factor for controlling of weight loss. The results of modeling by GA-ANN showed that a network with 7 neurons in the hidden layer with sigmoid activation function can predicted the weight loss (R=0.99) of button mushrooms dried by infrared system-hot air method.

Nowadays, increasing the nutritional value of pasta by adding nutritional materials is significantly important. Since surimi, having a high concentration of myofibril protein which has a high potential to improve nutritional characteristics of the pasta. This study aimed to investigate the use of surimi in preparing macaroni as well as its effects on chemical, cooking and sensory properties. Pasta samples were made from flour blended with 7%, 16%, 25% surimi and to be compared with standards. According to the results, appearance of all samples (before and after cook) was no defects. Increasing the level of surimi, the studied factors improved accordingly; protein and moisture content increased by 13.6% and 10.9%, respectively. Also by increasing the surimi content of ash, were increased. The difference of pH in samples was not significant. Results showed that by increasing the surimi, the cooking loss and cooking weight were increased. Samples with 25% had been suitable in taste. Samples with 16% had been stables in smell and Samples with 25% and 16% surimi had been suitable in general acceptability. Findings shows, it might be recommended to produce pasta enriched with surimi. Adding surimi to macaroni in amount of 16% showed better quality (, cooking and sensory characteristics).

In the present research work, response surface methodology was used to achieve optimum condition to prepare orange peel oil – quince seed mucilage (QSM) and maltodextrin (MD) emulsion and using this emulsion in microencapsulation. For this purpose and in order to access stable emulsion, effect of three independent variables including orange peel oil concentration (15-25% w/w), QSM/MD (0.015-0.02) and solid concentration (QSM+MD) (25-35% w/w) on the three dependent variables including droplet size, creaming index and viscosity were investigated. Optimized emulsion (25% solid concentration, 0.02 QSM/MD and 0.025 orange peel oil concentration) were dried by freeze dryer, and were kept in three temperature (4, 25 and 42oC) in order to investigation its stability during 6 week storage. The results showed that rheological properties of QSM, in particular its viscosity, had the highest effect on the stability and properties of emulsions and QSM could make quite stable emulsion over time. Also, our results revealed that half-life and release rate of encapsulated samples were significantly lower than control samples.

The lipase is used broadly in different industries such as food, drug, petroleum and detergent industry due to the catalyst ability of wide range of conversion reactions such as hydrolyzed, esterification and transesterification. Yeasts are one of the main generators of lipases. In this paper, we use RSM and CCD in order to examine the effect of PH (5.5-7.5), time incubator (3-7 days) and sesame meal extracts added to experimental medium (0-100%) on lipase generation and activity, generated biomass of Cryptococcus albidus and optimization of lipase generation process and generated biomass. The results showed that the percentages of sesame meal extracts added to experimental medium and time incubator are the most effective factors on lipase generation and activity and amount of generated biomass, respectively. Based on conducted experiments, optimized conditions of lipase generation and amount of generated biomass are determined PH 5.56 time incubator 7 days and percentages of sesame meal extracts added to experimental medium 100 percent in order to achieve maximum lipase activity (98.96 unit enzyme) and cell dry weight (1.14 gram per 100 mili liter medium).