جستجوی مقالات مرتبط با کلیدواژه « ذرت » در نشریات گروه « صنایع غذایی »

Resistant starches are classified in the category of indigestible starches and are introduced as a prebiotic product, which has lower calories and is cheaper compared to other dietary fibers. Therefore, the purpose of this research is to use type III resistant starch produced by thermal method at levels of 0, 5, 10, 15, 20, 25 and 30% in a completely random design as a substitute for wheat flour in biscuit, doughnut and cookie formulation. The results showed that by replacing wheat flour with resistant starch in the formulation more than 20%, the moisture content and water activity of the final product increased and decreased respectively. The specific volume and porosity of the doughnut were stable up to the level of 15% of resistant starch and then decreased. Also, the sample containing 15% resistant starch had the lowest amount of firmness in all the products. On the other hand, with the replacement of resistant starch in the formulation of the examined products on levels of 15% and above, the amount of L* value increased and the a* and b* values were decreased. The panelists also introduced the sample containing 15% resistant starch as the best sample. Therefore, it can be said that by replacing 15% of wheat flour with resistant starch, in addition to maintaining the physicochemical, textural and sensory characteristics of the final product, it is possible to enrich these snacks and the consumer can benefit from the benefits of using prebiotic products.

Celiac patients require a non-gluten-free diet. Therefore, the aim of this study was to investigate the characteristics properties of bread made from two types of simple corn flour and pre-gelatinized corn flour with microwave. For this purpose, a completely randomized design was used (P <0.05). Investigation of changes in the properties of simple and pregelatinized flour using a scanning electron microscope showed that the corn flour structure was coherent, while the structure of pre-gelatinized corn flour granules was degraded due to the microwave thermal process and was more structural expansion and swollen. Based on the results, it was determined that the pre-gelatinized corn flour sample had the highest porosity (16.5%) and the minimal texture firmness at the time of 2 (9.7 Newton) and 72 hours (17.2 Newton) after baking. Also, the use of pre-gelatinized corn flour increased the colorful component of L* , while no significant change was observed in the on two colorful components a* and b* . Finally, by examining the results of the sensory test, a sample containing pre-gelatinized corn flour was able to obtain more points from sensory evaluators by compared with of simple corn flour.

Nowadays, studies have been developing in order to use antimicrobial properties of plants instead of using synthetic preservatives. Jujube is one of the famous herbs. Jujube (Ziziphus jujube. Mill) belongs to family of Ramnaseh and native to the central areas of the Iran plateau. The fruit, leaves and root of this plant have medicinal and wellness properties. In this study, evaluated some physico-chemical of jujube extract (Extraction yield, Moisture, water activity, Fat content, Ash, Brix) and its effect on the mold of Aspergillus flavus. Extraction of dried and Ground jujube fruit was done by soaking with Hydroethanol solvent. Chemical composition of the extract was determined by GC-MS method. So the evaluated minimum inhibitory concentration (MIC) and the minimum fungal concentration (MFC) of extract against Aspergillus fulvous (PTCC 5004) by the dilution method in a liquid medium. In the next step, different concentrations of the extract were sprayed on corn grains and after placing a disk containing suspension of Mold spores in each petri dish. Growth of mold on corn grains was measured during 7 days. The results showed that the hydroethanolic extract of jujube fruit has an anti-mold effect against Aspergillus fulvous and the minimum inhibitory concentration of extract in the culture medium was determined 350 μg / ml and there was not observed any lethality at concentrations less than 1000 μg / ml. The minimum inhibitory concentration of the extract in the blanched corn grain medium was 5000 μg / ml. Therefore, the hydroethanolic extract of jujube fruit has an inhibitory effect on Aspergillus flavus but does not have the inactivation effect on this mold and its spores.

Rice and corn flours are appropriate alternatives for developing gluten free products and modification of some of their properties such as water absorption index of flour due to extrusion process could be effective for improvement of gluten-free products quality. In this research, addition effect of extruded flour in 110 °C with 18% feed moisture, in four levels ( 0, 10, 20 and 30%) and hydrocolloids of xanthan and hydroxypropylmethylcellulose in two levels ( 0.5 and 1%) of each were studied in gluten-free bread formulation. The results were proved significant effect of extruded flour and hydrocolloids addition on evaluated characteristics so that specific volume and porosity were promoted with increasing level of extruded flour till 10%, but higher levels were caused reduction of these properties. Also, increasing of extruded flour  level was decreased crust L* and hydroxypropylmethylcellulose had more effect on crumb hardness reduction of gluten free bread in compared to xanthan. Finally with regard to features such as specific volume, porosity, softness, color and scores of sensorial test, gluten free bread formulation including 10% extruded flour and 1% HPMC was determined as appropriate formulation which had specific volume of 3.01 cm3/g, porosity of 65% and overall acceptance score of 4.1 in sensorial test.

In this research, optimization of the formulation of corn-based gluten-free bread with egg white protein and the microbial transglutaminase enzyme was conducted with the purpose of minimizing baking loss and hardness, and maximizing the specific volume, bread height, porosity and color index L* by the response surface method and finally, estimating these responses with the help of the neural network. The effects of the two concentrations of microbial transglutaminase enzyme in the range of 0 to 1.5% and egg white protein in the range of 0 to 6% with the help of the central composite design on specific volume parameters, baking loss, porosity, bread height, hardness and color indices L*, a* and b* of bread crust were investigated. Investigating the results indicated that the optimum conditions for the production of gluten-free bread based on maize is created when the enzyme and egg white protein concentrations are 0.65% and 6%, respectively. By increasing the enzyme concentration, baking loss, porosity and a* index increased, but the b* index decreased. The results also indicated that by increasing the enzyme concentration in the formulation of samples, we firstly observed increase and then decrease in bread height and specific volume. Increasing the protein concentration of egg white in maize-based gluten-free bread formulation resulted in an increase in L* and a* indexes, and a decrease in baking loss and b* index. The results of artificial neural network modeling indicated that a network with a hidden layer containing 9 neurons, with an 8-9-2 layout (a network with 2 inputs, 9 nodes (neurons) in the hidden layer and 8 outputs), had the best result in predicting the mentioned outputs. This network indicated the highest accuracy among the mentioned topologies with a correlation coefficient of 1.00 and mean square error of 0.0011.

Fusarium graminearum is one of the main zearalenone producing source Fusarium species that can contaminate cereals such as corn. Considering the health risks of contamination with trichothecenessource fungi in cereals, in this study, contamination with zearalenone-producing Fusarium in corn samples collected from industrial and non-industrial farms in Razavi Khorasan Province was evaluated. In order to develop a simple method for detection of zearalenone, after cultur-ing these samples using pour plate technique, the isolates were purified through single-spore technique. All the Fusarium graminearum were identified by through PCR method using genus specific Tri5-F/R and Pks4-F/R as primers. 5 Of the 8 identified Fusarium graminearum isolates wich were tested with Tri5-F/R set of primers scored positive, and an amplicon with a size of 380 bp was obtained out of them which reveals their ability to produce trichothecenes. From these isolates, an amplicon of the size 280 bp was obtained after they scored positive with Pks4-F/R set of primers; which by itself shows the existence of Fusarium graminearum with the ability to produce zearalenone .These data indicate that, the developed PCR trend is a powerful, specific and sensitive tool to detect potential zearalenone contamination in food or feed production. Paying attention to the presence of toxigenic fungi on these corn samples, it is necessary to design some complementary investigation, decide health regulations and supervise their execution. Finally attention of public health and nutrition experts is essential too.

Celiac Disease (CD) is a common lifelong disorder with small bowel malabsorption and gluten intolerance. The only effective treatment for CD is a strict adherence to a gluten free diet throughout the patient’s lifetime. One of the main challenges in relation to the gluten free bread is to obtain a proper structure and quality. Gluten free breads require polymeric substances that mimic the viscoelastic properties of gluten to provide structure and retain gas. In this research effect of tragacanth in three concentrations (0.5, 1.25 and 2%) and pectin-tragacanth in concentration of 1.5% (1:1) was evaluated on the physicochemical, textural and sensory properties of corn-based gluten-free bread. Specific Volume of the breads was enlarged as the concentration of tragacanth increased compared to the control sample. The lowest weight loss of samples was belonged to the bread containing2% tragacanth that had not significant difference with the sample containing 1.25% tragacanth. With increasing of tragacanth concentrations a significant )P<0.01) increase in moisture content of the sample crumb was observed compared to the control bread. Crumb hardness increased during storage from first to third day and the effect of treatment on crumb hardness was significant )P<0.01). Bread containing 1.25% tragacanth had a softer texture compared with other breads containing hydrocolloids and control bread. However, this difference was not significant (P>0.05). Also the results showed that treatment effect on the sensory properties was not significant (P>0.05), and addition of different concentration of hydrocolloids improved the overall score of sensory evaluation. Generally, according to the results of different tests and statistical analysis which carried out in the present study, it was suggested that the addition of tragacanth in concentration of 1.25% can improve the gluten-free bread quality.

Celiac disease is a permanent intolerance to some cereal prolamins and this disease is one of the most common food allergic. The only effective treatment for such patients is gluten-free diet. Gluten free breads require polymeric substances that mimic the viscoelastic properties of gluten to provide structure and retain gas. In this research effect of pectin in three concentrations (1, 2 and 3 % flour basis) and also combination pectin-tragacanth in concentration of 3 % was evaluated on physicochemical, textural and sensory properties of corn-based gluten-free bread. Addition of pectin and increasing its concentrations increased the volume specific in breads containing hydrocolloids as compared to the control bread, and among treatments pectin in concentrations of 3% showed the highest loaf specific volume. The lowest weight loss of bread was belong to bread with 2% pectin that was not significant with breads contain to 1 and 3% of pectin. Also addition of pectin caused a significant ( p

Dependence on a single product such as wheat and bread from that, is a serious threat to sustainable food security in the light of the limited resources in agriculture has always been threatened. So the aim of this study was to investigate the possibility of replacing 30% of the wheat flour in baguette bread formulation, with a mixture of corn flour and potato flour at three levels of 20-10, 15-15 and 10-20%, by using of guar gum in levels of 0, 0.25 and 0.5%. The changes of physicochemical, visual, textural and sensory properties of final product was studied in a completely randomized factorial arrangement test (p

This research carried out in order to corn kernels drying by using a discontinuous rotary drum dryer. This research evaluated the effect of drying air temperature and velocity of the rotating cylinder parameters on the drying time, breakage percentage, cracking, burn kernels and the disruptive energy of corn kernels. For this purpose, a batch dryer rotating cylindrical drum rotation is designed and developed. Intake air temperature parameter Was considered at four levels of 40, 60, 80 and 100 °C and the drum rotation speed at three levels of 2, 6 and 10 rpm. The results indicated significant interaction effect of temperature and speed rotation cylinder on maize grain drying. The lowest time kernels corn drying and the cylinder rotation speed was at 100 °C and 2 rpm, respectively. With increasing temperature of dryer from 40 to 100 °C, grain drying time is reduced to less than a quarter but; with increasing rotation speed of the cylinder drying time was increases. During the drying process, the interaction of temperature and rotation speed of the cylinder has no significant effect on broken kernels-corn. The maximum percentage of broken grains of corn is in 10 rpm rotation speed. Interaction of temperature and rotation speed of the cylinder is significant at the one percent level on cracked and burned grains. The More of the cracks and burn is in 100 °C temperature and 2 rpm of rotation speed.

Corn tortiilas are flat breads made from corn dough (masa) which is prepared through the nixtamalization process (alkaline cooking). Corn, in nixtamalization, is cooked in a lime solution then the boiled maize is steeped in cooked liquor, following by washing out and milling to obtain wet masa flour. Drying wet masa flour in air oven produce dry masa flour. Cooking temperature, cooking time, lime concentration, and steeping time significantly affect the quality of masa flour and final product(tortilla). In this research the cross effects of these four factors, to determine the best treatment for production of masa flour, were studied. Effects of cooking temperature (75,85,95°C), cooking time (0,30,60 min), lime concentration(0, 0.5, 1%) and steeping time (10,14,18 hr) by measuring pH, protein content, ash content, color parameters, water absorption index (WAI) and using central composite design were investigated. Statistical analysis revealed the best treatment for production of masa flour as: cooking temperature 85°C, cooking time 30 min, lime concentration 0.5%, and steeping time 14 hr.

Preparation of Gluten-free bread using gluten-free cereals appears to be necessary for people with Celiac disease in which the patients suffers from gluten sensitivity. For this purpose, blends of corn and chickpea at concentrations of 80/20, 60/40, 40/60 and 20/80 with 3% HPMC gums to provide this type of bread was studied. For quality evaluation of breads, some factors such as; specific volume, density, oven spring, shape index (height/width ratio), porosity, texture analysis and microstructure were studied. The texture and microstructure of samples were investigated within first& second days and 24 hours after cooking, respectively. Overall, by making gluten-like network in the bread crumb, chickpea flour was able to increase the specific volume, oven spring, shape index and porosity, and decreased the gluten-free bread density accordingly. Chickpea flour increases moisture content of the gluten-free bread and decreases hardness of the bread crumb as the result. According to all performed tests, it was shown that a formulation of 20% maize flour with +80% chickpea flour has greatest effect on improving the quality.

In this research, effect of the chickpea flour and maize combination in different concentrations 20, 40, 60 and 80 % (w/w) and addition of 3% (w/w) hydroxy propyl methyl cellulose gum, on the staling properties of gluten-free bread was investigated. Moisture content of bread was determined during the 1st, 3rd and 6th days according to a standard method. Gluten-free bread texture also evaluated during the days 1 and 2 using a texture analyzer and the peak temperature and enthalpy of the samples also evaluated in 1st, 3rd and 6th days using the differential scanning calorimeter. Considering the acquired data an increase the percentage of chickpea flour increased moisture content of the gluten-free bread leading to less firmness, and too with increasing in percentage of chickpea flour reduced enthalpy and peak temperature of the gluten free bread leading to staling later. Altogether, according to the result obtained from staling tests using 20% and 80% of maize flour and chickpea respectively in a gluten- free formulation had the most effect in retarding the staling.