جستجوی مقالات مرتبط با کلیدواژه "نان بربری" در نشریات گروه "مکانیزاسیون کشاورزی"

As the most important source of calories and protein, bread has a special role and importance in the nutrition of the country, and its cheapness has caused it to replace other food items in the diet in recent years. The increase in bread consumption in the low-income and vulnerable groups has been more intense due to the low volume of supply of other food products and the excessive and continuous increase in the price of other alternative products. Flat bread has the highest consumption statistics among other breads in Iran. One of their types is Barbari bread, which is the second most consumed bread after lavash bread in Iran. Therefore, the health and quality of consumed Barbari bread is of particular importance. For this purpose, this study was conducted with the aim of the effect of storage time of Barbari bread based on the characteristic of smell using the olfactory machine system based on eight metal oxide semiconductor sensors.

An odor machine system based on eight MOS sensors was carried out in order to investigate the effect of bread storage time based on odor characteristics. Designed system includes data acquisition system, sensors, shield of sensors, sample container, power supply, connections, electric valves, air pump and air filter. The sensor array was consisted of the 8 MOS sensors that each one reacts to specific volatile compounds. These sensors are widely used in olfactory machines because of their high chemical stability, high durability, low response to moisture and affordable prices. These are the most commonly used sensors in electronic nose system. Sensors are the main components of an electronic nose system therefor it is necessary to select the able sensors to detect differences among samples. In order to carry out the test, the sample was placed in sample container and in the baseline correction step (150 seconds), clean air was passed through the sensors to transmit the response of sensor array to steady state. At the injection step (180 seconds), the sample headspace was transmitted and passed through sensors chamber. Output voltage of each sensor depends on the type of sensor and its sensitivity. At the cleaning step (150 seconds) the clean air was passed through sensors to get the sensor array responsive to a stable state. Also, at this step the pump removed the odor remaining inside the sample container and system is prepared for the next test. The signals obtained from the sensors were recorded and then pre-processed.

The olfactory machine system based on eight metal oxide semiconductor (MOS) sensors was investigated with the PCA pattern recognition method due to the storage time of Barbari bread at four different temperatures. The data obtained from the signals processing with fractional method were used as input of PCA. The results of principal component analysis with two components PC1 and PC2 are 95, 90, 86 and 85%, respectively, for Barbari bread that is stored at room temperature (in the table), refrigerator temperature (4°C), room temperature (in foil) And the temperature of the freezer was placed, it showed. The results obtained from the QDA analysis to determine the quality of Barbari bread at 4 °C for 9 days, at room temperature (in foil) and (on the table) for 5 days and Barbari bread at the freezer temperature of the refrigerator (-18 °C) for 15 days of storage with classification accuracy of 98.52, 96, 100 and 97.35% respectively. The results of LDA analysis for the signals obtained from the olfactory machine, in the classification of the duration of storage of Barbari bread at refrigerator temperature, room temperature (in the table), room temperature (in foil) and refrigerator freezer temperature, respectively, with classification accuracy of 79.26 and 85.33, 78.67 and 75.22 percent were obtained. Also, according to the output obtained from the loading linear graphs and the radar graph, the smell of Barbari bread has the most and the least effect on the MQ9 sensor and the TGS813 sensor, respectively

An olfactory machine system based on eight metal oxide semiconductor (MOS) sensors was investigated for the Barbari bread time retention effect at four different temperatures. The results of principal component analysis with two components PC1 and PC2, for Barbari bread at room temperature (the table), refrigerator temperature, room temperature (in foil) and It showed that they were exposed to freezing temperatures. The results obtained from QDA analysis to detect the quality of Barbari bread at 4°C in room temperature (in foil) and (in the table) and refrigerator freezer temperature respectively. The results of LDA analysis for the classification of Barbari bread at refrigerator temperature, room temperature (in the table), room temperature (in foil) and freezer temperature of the refrigerator. The was obtained. Also, according to the output obtained from the loading linear graphs and the radar graph, the smell of Barbari bread has the most and the least effect on the MQ9 sensor and the TGS813 sensor, respectively.

In the baking industry، use of hydrocolloid technology to improve the operation and to increase the tolerance to paste fermentation conditions، improve quality and increase the shelf life of fresh as well as stored bread، is of large applications. This research was carried out to evaluate the effects of gel of sodium alginate on rheological properties of dough and quality (volume، specific volume، cooking loss and water activity)، sensory properties and staling of Babary bread. Hydrocolloidsof sodium alginate were added at 0. 5%، 1%، 1. 5% w/w levels (flour basis) towheat flour. The rheological properties measurement of the dough and of staling of breads were investigated using Farinograph and Instron instruments، respectively. Results of rheological evaluation of dough showed thataddition of gel، leades to increase in the water absorbtion capacity، dougharrival time in line of 500 BU، dough development time، dough stability، dough departure time of line of 500 BU and time to breakdown، while the dough degree of softening after 10 and 20 minutes past and mixing tolerance index got decreased in comparison with control. Results in an evaluation of bread water activity showedthat addition of hydrocolloiddecreased bread water activity. Results related to an evaluation of the properties of technology of bread showedthat an addition of gel at a level of 1. 5 percent increased volume as well as specific volume of the bread. The results of staling tests done within the three times of 24، 48 and 72 hours showed that addition of sodium alginate (0. 5، 1، and 1. 5%) on dough، the rate of bread’s crumb staling decrease significantly (p<0. 05). Also، breads containing sodium alginate benefitted from a lower rate of staling than the control samples. In other words، bread samples containing 1. 5% sodium alginate and control samples were of the least and the most staling rates. In relation to sensory evaluation of bread samples، it was revealedthat the addition of hydrocolloidof levels of 1. 5 percent exerted the strongest positive effects on some sensory properties of the bread.

The effect of Xanthan hydrocolloid (0.1 and 0.5% W/W of flour) on physical and sensory properties of the fresh and stored Barbary bread were studied. Effects of hydrocolloids on physical properties of baked bread were determined by different tests of: penetration, colorimetry (Hunter values) of crust and Differential Scanning Colorimetry (DSC). Sensory evaluation also was carried out for determining the overall acceptability of the bread samples. All the experiments, except colorimetry, were carried out on the first, second and fourth days after baking. With an addition of Xanthan, physical and overall acceptability of the bread were improved. Xanthan gum increased dough consistency, water absorption, dough developing time as well as the softening index. Furthermore, it increased yellowness and lightness indexes of the crust and softness of the crumb in the bread experimental samples. The bread samples containing Xanthan gum at 0.5% level showed the highest quality accompanied by the least unfavorable change during their storage time.

This study examined sourdough LAB containing specific starter cultures used to produce barbari-style bread and evaluated their microbiological shelf life and sensory properties. The effects of sourdough fermentation time (8, 16, 24h), fermentation temperature (28, 32, 36°C) and type of starter culture (Lactobacillus sanfransicencis, ATCC 14917; Lactobacillus plantarum, ATCC 43332; a mixture of both LABs) were analyzed in a completely randomized design factorial experiment with four replications. The microbiological shelf life of samples was determined by placing serial dilutions on plate count agar for one to seven days. The sensory properties of the bread were determined 1, 24, 48 and 72h after baking using AOAC standards. The results showed that sourdough had a significant effect (p≤0.05) on improving the microbiological shelf life and sensory properties of barbari bread in comparison with the control sample. Moreover, the sample produced with Lactobacillus plantarum (24h fermentation time and 32ºC fermentation temperature) had the maximum microbiological shelf life and the sample produced with a mixture of both LABs (16h fermentation time and 28ºC fermentation temperature) had the best sensory evaluation 72 h after baking.