Post-harvest technology
Esmaeil Mirzaee- Ghaleh; Fardin Aayri Samlhe; Amir Hossein Afkari Sayyah
Abstract
Introduction 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 ...
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Introduction 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.Materials and Methods 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.Results and Discussion 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, respectivelyConclusion. 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.
Soil Chemistry and Pollution
Narges sousaraeS; Mojtaba Baranimotlagh; Farhad Khormali; Esmaeil Dordipour
Abstract
Introduction Biochar is a charcoal, pyrolyzed from a wide range of carbon-rich biomass materials, such as crop and wood residues, animal manures and a range of industrial wastes and once added into soil, it can store the soil carbon for a long period, improve the soil structure and increase the crop ...
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Introduction Biochar is a charcoal, pyrolyzed from a wide range of carbon-rich biomass materials, such as crop and wood residues, animal manures and a range of industrial wastes and once added into soil, it can store the soil carbon for a long period, improve the soil structure and increase the crop yield. However, the physical and chemical characteristics of biochars are influenced by the properties of the feedstock and pyrolysis conditions, such as highest temperature treatment and furnace residence time. Considering the large variation in biochar properties, it is not surprising that crop yields vary with different biochars. We investigated the effects of biochars on corn growth in the greenhouse. The specific objectives were (a) to assess whether feedstock properties or pyrolysis temperature are important in preparing of biochar and (b) to quantify the effects of varying biochar characteristics on corn growth and chlorophyll index in a calcareous soil under greenhouse condition. Materials and Methods Biochar was produced from crop residues including rice, cotton and canola. Feedstock was oven-dried before pyrolysis. The pyrolysis process was conducted for 1 h at 10°C min‒1 heating rate to produce biochars at different temperatures of 350 and 700 oC under oxygen-limited conditions. All biochars were ground and passed through a 2-mm sieve before experimentation. Ash content and char yield was calculated and biochar pH and electrical conductivity (EC) were measured using 1:20 solid: solution ratio. The soil used in this experiment was taken from the Research Farm of Gorgan University of Agricultural Sciences and Natural Resources. The soil was air-dried and ground to pass through a 2-mm sieve then analyzed for various soil physico-chemical properties using standard methods. A greenhouse experiment was set up using pots with 5 kg prepared soil. Various treatments comprising of 3 biochars type produced at different pyrolysis temperatures (350 and 700°C) from three crop residues (rice, cotton and canola) at three application rates (0, 2 and 5% w/w). A completely randomized design was used in factorial arrangement and treatments were replicated four times. After the soil had been prepared and biochar added, six seeds of maize were planted approximately 20 mm deep in the center of the pots and thinning to seedlings of four plants pot‒1 was done at plant establishment. Distilled water was used to maintain moisture contents of the soil in all the pots during the experimental period. Plant stem and leaves were harvested 96 days after planting. Washed with distilled water then dried with tissue paper. The leaf and stem samples were air-dried and then oven dried at 65˚C to a constant weight in a forced air driven oven. The studied traits included leaf and stem fresh and dry weight, plant height, number of leaves, time to first flowering, chlorophyll index (SPAD), concentration of chlorophyll a, chlorophyll b and total chlorophyll. The analysis of variance (ANOVA) with the factors biochar type, application rate and pyrolysis temperature were performed using a completely randomized design. Significantly different treatment means were separated using least significant difference (LSD) test at PResults and Discussion The results showed that pyrolysis temperature significantly influenced the measured chemical properties of biochars. EC values were tended to increase with pyrolysis temperature. The pH of the biochars was also influenced by temperature. Biochars pH ranged from 6.8 to 9.6. The pH of the biochars was increased with increasing temperature and highest pH (9.6) was observed at 700°C of rice residues. These increases in pH values are mainly due to separating of alkali salts from organic materials by increased pyrolysis temperature. The results showed that the yield of biochars was reduced by increasing pyrolysis temperature and ranged from 19.4% to 40.1%. This decline in yield content is mainly due to the destruction of some compounds such as cellulose and hemicellulose as well as combustion of organic materials with increased pyrolysis temperature. By contrast to biochar yield, the biochar ash content increased with increasing pyrolysis temperature. The lowest values of leaf and stem fresh and dry weight was observed at 700°C of canola residues. These results suggest that biochar produced at high pyrolysis temperature (especially at 700°C), when applied to the soil, may increase soil salinity and subsequently provide undesirable impacts on the plant growth. It has been reported that the negative impacts of high salinity on the plant growth could be due to the following reasons: (1) the low osmotic potential of the soil solution, resulting in water stress, (2) specific ion effects, resulting in salt stress, and (3) nutrient imbalances. Addition of each three types of biochars caused a significant increase in chlorophyll concentration compared to control. Conclusion The type of feedstock material is an important factor that determines the final application of the biochar and its effect on plant growth papameters. Therefore, there is further need for research focusing on the effects of biochar addition on soil properties and plant growth in order to assess biochar as a valuable resource for agriculture.
R. Montaghami Rad; E. Ahmadi; S. Zarif Neshat
Abstract
Introduction Storage conditions of product after harvest and during storage are important factors that affect the quality parameters of the products such as color and mechanical properties. The observance of effective issues on the fruit quality, ...
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Introduction Storage conditions of product after harvest and during storage are important factors that affect the quality parameters of the products such as color and mechanical properties. The observance of effective issues on the fruit quality, such as weather conditions, harvest methods, timing of harvesting, temperature of storage and time of storage in maintaining of olive quality and reduce waste, will be very effective. Performance of mechanical testing and mechanical and colorimetric properties of products has an important role in study of qualitative and quantitative properties during storage. Moreover, the study of color and mechanical properties of products, such as olive is necessary, for use in machine design for processing and recovery processing lines in order to reduce waste. Materials and Methods In this study, two types of olives, bitter and sweetened with 1.5% NaOH were harvested and tested to study the effect of storage time on their color and mechanical properties. Olive fruits were stored in two temperatures (environmental conditions with 25 and refrigerator with 4) for 3 months. During this period, experiments were carried out at the intervals of 10 days. Universal testing machine and color meter devices were used for determining the mechanical properties and the color of olives, respectively. By performing a factorial experiment under completely randomized design, the effects of independent factors including storage time, storage temperature and type of olive on the measured properties (shear modulus, shear force, shear energy, modulus of elasticity, penetration force, yield strain, L*, a*, b*, h and c*) were studied. Results and Discussion The results of analysis of variance for shear modulus showed that the main effect of olive type, temperature, time of storage and the dual effects of these parameters were significant at the level of one percent. Analysis of variance for shear force showed that the effect of type, temperature, time of storage and interaction effects of type× temperature and type× time of storage were significant at the level of one percent. The results of data analysis for shear energy showed that the independent parameters, including the type, temperature, time of storage and the effects of dual and triple of their were significant at the level of one percent. According to the graphical results, shear modulus and shear energy of any type of olive on the thirtieth day with the fast steep increased. Water surface evaporation, changes in the texture of olive and a sharp drop in humidity are reasons for the sudden increase of shear modulus and shear energy on the thirtieth day. With increasing time of storage, shear strength and other mechanical properties for bitter and sweet olive increased. This result conformed to the results of Lavassani et al and Nanos et al. Analysis of variance of mechanical properties for olive fruit in penetration test showed that the effect of type and interaction effects of type and time of storage on modulus of elasticity were not significant. Analysis of variance of yield strain showed that the only effect of type was significant at the level of one percent. The results of mean comparison with Duncan test showed that during storage, penetration force and modulus of elasticity for bitter and sweet olive increased. This result correlated with the results of De Castro et al. The penetration force, yield strain and modulus of elasticity of sweet olives during storage were higher in comparison to bitter olives. The penetration force and modulus of elasticity of bitter and sweet samples stored at 4 were higher in comparison to the same sample in temperature of 25. This result correlated with the results of Nanos et al. Analysis of variance of colorimetric properties showed that the interaction effects of type and time of storage on L* were not significant. The effects of type and time of storage on a* and all effects on b* and c* were significant at 1% probability level. The results of mean comparison showed that the brightness and yellow of bitter and sweet samples increased with increasing time of storage compared to the first, tenth and twentieth days. The increase in L* and b* color characteristics correlated with the results of Piga et al. Color characteristics L*, b* and c* of bitter samples in each of the temperatures and days of storage were higher in comparison to sweet samples. In addition, the values of L*, b* and c* of bitter and sweet samples stored at 25 were higher in comparison to the same samples in temperature of 4. Conclusion The results of mechanical and colorimetric tests showed that by increasing the storage time, stiffness, shear strength and other mechanical parameters increased in both types of olives, and the L* and b* values of the samples were higher in comparison to the first, tenth and twentieth days. Bitter and sweet samples stored at 4 temperature displayed higher stiffness, modulus of elasticity, shear modulus, shear force and shear energy values and lower L*, b* and c* in comparison with the same samples stored at 25 temperature.
