Effects Of Carbon Dioxide Concentration Research Articles

Effects of carbon dioxide concentration in modified atmosphere packaging on the shelf life and quality criteria of whole wheat bread during storage

AbstractThis study aimed to determine the effects of carbon dioxide concentration in modified atmosphere packaging (MAP) on the quality criteria and shelf life of whole wheat flour bread. Four different concentrations of CO2 and N2 gases (30% CO2 + 70% N2, 50% CO2 + 50% N2, 70% CO2:30% N2 and 100% CO2) were applied to the bread samples, which were packaged with PA/EVOH/LDPE (polyamide/ethylene vinyl alcohol/low‐density polyethylene). The samples were stored at room temperature (25°C ± 1°C) for 13 days. The control group was packaged using BOPP (bi‐oriented polypropylene) under atmospheric air as in traditional current use. The effects of MAP on headspace gas analysis, pH, moisture content, water activity, water‐holding capacity, blue value, hardness, total mould and yeast count and sensory evaluation were analysed on days 0, 3, 4, 5, 7, 10 and 13. The results showed that the most effective gas combination in extending the shelf life of whole wheat bread was 100% CO2, and its shelf life was 10 days, whereas it was only 3 days for the control group. Increasing concentrations of CO2 significantly affected mould and yeast growth. As the CO2 concentration increased, the bread exhibited higher water‐holding capacity and blue values, which are important indicators for bread staling. An improved preservation of sensory properties was observed in proportion to increasing CO2 concentrations. However, the CO2 gas concentration did not affect the hardness of the bread. Overall, the study suggests that MAP technology, particularly using 100% CO2, can effectively extend the shelf life of whole wheat flour bread without the need for preservatives, not only extending the microbiological shelf life but also increasing the sensory shelf life. The species that grew in air‐packaged samples were suppressed under modified atmosphere conditions and chalk mould fungi were the dominant and shelf life‐impacting species in the MAP samples. These findings could be beneficial in reducing bread wastage, which is a critical issue in today's society due to the limited shelf life of bread caused by rapid microbiological deterioration or staling.

Effect of carbon dioxide concentration on the combustion characteristics of boron agglomerates in oxygen-containing atmospheres

Effect of carbon dioxide concentration on the combustion characteristics of boron agglomerates in oxygen-containing atmospheres

Assessment of carbon dioxide effect on agricultural crops productivity by the method of dispersion analysis

This article studies the influence of carbon dioxide in the atmosphere on the yield and quality of grain crops. To make the right estimate the authors have chosen the method of dispersion analysis. The objects of the study are the yield of spring crops in Russia and the yield of spring wheat in the Saratov region. The impact turned out to be statistically significant. It is estimated at 43% for Russia, and 80% for spring wheat (Saratov region). The effect of carbon dioxide on grain quality (protein content) has also been studied. The results were quite uncertain. It was found out that the effect of carbon dioxide on the protein increase in spring wheat was 80% with a small correlation coefficient (0.015). It became obvious that the relationship between the growth of carbon dioxide concentration and grain quality is quite complex and cannot be described by a simple linear relationship, unlike the relationship between CO2 concentration and yield of spring crops. The following important methodological conclusion was made: to make the right conclusion about the effect of carbon dioxide concentration on grain quality using the method of dispersion analysis we need special conditions for the formation of initial samples.

The Effects of Carbon Dioxide Concentration on Residents in the Area of a Cement Plant in Perak, Malaysia

Nowadays, concrete is used extensively in construction. The cement factory must generate massive amounts of cement each year in order to deliver enough concrete. Carbon dioxide emitted during the cement manufacturing and raw materials transportation processes contributes to air pollution and greenhouse gas emissions, deteriorating air and water quality and posing health risks to residents. Hence, the purpose of this research is to investigate the effects of carbon dioxide absorption on local residents and their buildings. Therefore, the objectives of this paper are to determine the influence of carbon dioxide absorption on local residents’ health as well as the consequences on structures. A total of 375 questionnaires were distributed throughout the Perak cities of Kampar, Malim Nawar, and Kota Bharu. This research were conducted in Malaysia in 2019. It was decided to adopt convenience sampling. This paper’s findings are separated into two (2) sections: effects on local residents’ health, structures, and environment. According to the Pearson Correlation data, there are several dead cases, as well as locals suffering from cancer and other respiratory problems. The concrete, timber, and metal frames, as well as other faults on the door and windows, have all deteriorated significantly. To preserve human health and the environment, the government should tighten the rule on pollution discharge compliance, and all plant owners should be accountable for building a buffer zone and installing industrial air filters surrounding their factories.

Investigating the effect of carbon dioxide on the acidity of the Ocean

There is a significant effect of carbon dioxide on the acidification of the ocean. This research focuses on the acidification of the ocean and its effect on the animal life in the ocean. Also, it focuses on the effect of carbon dioxide concentration in the atmosphere on the ocean acidification. The data are collected from the research institutions and laboratories, such as National Snow and Ice Data Center (NSIDC), Japan, National Oceanic and Atmospheric Administration (NOAA), USA, Mauna Loa Observatory in Hawaii, and other sources of research about acidification of ocean. The results show that the acidity increases with increasing the amount of carbon dioxide in the atmosphere. This is because ocean absorbs nearly 50% of carbon dioxide from the atmosphere. Carbonate ions (CO32-) will be used in forming carbonic acid, which will increase the acidity of the water. Increasing the acidity of water will affect building of the animal Skeleton. It is recommended to reduce the amount of carbon dioxide in the atmosphere; therefore the acidity will be decreased in the ocean.

Thermal transport and chemical conversion in single reacting sorbent particles

AbstractThe effects of particle size and carbon dioxide concentration on chemical conversion in engineered spherical particles undergoing calcium oxide looping are investigated. Particles are thermochemically cycled in a furnace under different carbon dioxide concentrations. Changes in composition due to chemical reactions are measured using thermogravimetric analysis. Gas composition at the furnace exit is evaluated with mass spectroscopy. A numerical model of thermal transport phenomena developed previously is adapted to match the physical system investigated in the present study. The model is used to elucidate effects of reacting medium characteristics on particle temperature and reaction extent. Experimental and numerical results show that (1) an increase in particle size results in a decrease in carbonation extent, and (2) the carbonation step consists of fast and slow reaction regimes. The reaction rates in the fast and slow carbonation regimes increase with increasing carbon dioxide concentration. The effect of carbon dioxide concentration and the distinction between the fast and slow regimes become more pronounced with increasing particle size.

Comparative Effects of Carbon Dioxide Concentration in Modified Temperature and Pressure Conditions on Adults and Larvae of the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Three modified atmospheres with different CO2 concentrations (30, 40, and 50%) were tested against larvae and adults of the red flour beetle, Tribolium castaneum (Herbst), at 25 and 35 °C by using several exposure periods to detect the mortality percentages and lethal time (LT) values. The effect of CO2 under pressure (5, 10, and 15 bars) on the target insect was also evaluated at 25 °C and two exposure periods. Larval and adult mortality of 100% after four days at 35 °C was obtained with the modified atmosphere containing 50% CO2. The LT50 for adults was 6.8 days at 30% CO2 concentration and 25 °C and decreased to 1.8 days with 50% CO2 concentration at 35 °C, whereas larval LT50 was 3.9 and 0.8 days at the same CO2 concentrations and temperatures, respectively. At the highest tested CO2 concentration, significant larval sensitivity was observed after the first two days of exposure. Using CO2 under 15 bar pressure decreased the necessary exposure period to attain 100% mortality of adults and larvae from several days at normal pressure experiment to five hours.

Effect of Carbon Dioxide Concentration on Cereal Yield in Sudan

To estimate the long-term effect of carbon dioxide (CO2) emission on cereal yield in Sudan, we employed an autoregressive distributed lagged (ARDL) bound test for cointegration analysis. The ARDL results reveal evidence of cointegration between the dependent variable (cereals yield) and two independent variables (CO2 emission) and agricultural GDP. The estimation results of the error correction model indicate that change in CO2 has a positive and significant impact on the cereal yield in the long and short terms, as 1% increase in CO2 leads to a cereal yield increase by 3% in the short term and by 0.7% in the long term. This result adds two important findings to the existing literature: First, the positive impact of CO2 on cereal yield in Sudan supports previous research findings in other countries of warm and arid climates. Second, the effect of CO2 on cereal yield differs from short to long term, as our finding indicates that CO2 has a greater positive effect in the short term compared to that in the long term, implying that the effect of CO2 on cereal yields is not linear, as commonly perceived, but it decreases as time duration extends to longer periods. This may be due to the CO2 effect on global warming that emanates from cumulative CO2 concentration, which leaves a disproportionate impact on crops over time.

The effects of carbon dioxide concentrations on some morphological and physiological characteristics of ligustrum vulgare

Carbon dioxide is one of the most important necessary factors for plant growth. In order to study morphological and physiological response of ligustrum vulgare to Co2 enrichment, one-year-old seedlings of this species exposed to different carbon dioxide concentrations for two months. Treatments included 450 (control), 750, and 1100 ppm Co2. The experiment was based on a completely randomized design with three replications. Then some morphological and physiological characteristics were measured. Results showed Co2 concentrations of 750 and 1100 ppm increased all morphological traits (except collar diameter and root dry weight) and physiological characteristics such as proline, chlorophyll a and nitrogen. The highest amounts of proline, chlorophyll a and nitrogen were observed at concentration of 750 ppm. The amount of increase in proline was about 4-fold compared to the control. The study concludes that the increased carbon dioxide concentration in the future maybe improve the growth of this plant.

Adaptation of the Cyanobacterium fischerella sp. ISC 107 to the combined effects of pH and carbon dioxide concentration.

The aim of this study was to investigate the adaptation of the cyanobacterium Fischerella sp. ISC 107to combined effects of carbon dioxide concentration, acidic and alkalinity. Axenic strain was incubated in BG0-11 medium. Carbon dioxide treatments were limited and relatively non-limited. Acidic (pH 5), neutral (pH7), and alkaline (pH 9) conditions were employed in each treatment. Survival, growth, chlorophyll, phycocyanin, allophycocyanin, and phycoerythrin contents were evaluated in each treatment along with ammonium liberation, frequency, and biometry of heterocyst. Results showed that like other explored stigonematalean and nostocalean cyanobacteria, this strain cannot grow in acidic condition. Under limited carbon dioxide condition, difference in growth rates were not significant between acidic and alkaline conditions; however, carbon dioxide enrichment caused significant increase in growth rates. Phycobilisome system of this strain lacked phycoerythrin and may complete its structure both at the core and the rod under alkaline condition. Heterocyst frequency and biometry were maximum at alkaline condition showing significant correlation with nitrogenase activity. Heterocyst showed cylindrical and sub-cylindrical morphology on days 4and 5 after inoculation. Overall, the results showed that this strain may be qualified to be used as a biofertilizer similar to the other cyanobacteria.

The effect of carbon dioxide concentration on growth of Pseudopediastrum boryanum biomass in a photobioreactor culture

The effect of carbon dioxide concentration on growth of Pseudopediastrum boryanum biomass in a photobioreactor culture

Elevated temperature and carbon dioxide concentration effects on wheat productivity in Madhya Pradesh: a simulation study

The Agricultural Production System Simulator (APSIM) Wheat model was used to test the sensitivity of wheat cropping system for the Bhopal region in Madhya Pradesh to changes in temperature (0 to 5°C from the base mean temperature) and atmospheric carbon dioxide concentration (0 to 550 ppm from the base of 350 ppm). The wheat cultivar Sujata was used for this simulation study. It was found that there was a negative relationship between grain yield and temperature while there were positive correlations of grain yield with atmospheric CO2 concentration for the region under study. However, the rate of decrease in grain yield was more for higher temperatures rise in contrast to lower temperatures, and the rate of increase in grain and biomass yield was more for higher CO2 concentration compared with the lower levels. On an average, there was 8% decrease in wheat grain and biomass yield per 1 °C increase in temperature. On the contrary, wheat grain yield increased by 33% and biomass yield by 35% with the elevation in CO2 concentration from 350 to 850 ppm. Increasing the temperature by1 oC and CO2 concentration to 500 ppm, the yield decline in wheat was lower than individual effect of increased temperature. This study showed that environmental factors have significant effects on wheat grain and biomass yield with changes in atmospheric CO2 and temperature. These findings provided a sound basis for preliminary coping and prioritizing adaptation options for the future climate change scenarios.

Biogenic Amines as a Quality Index in Shredded Cooked Chicken Breast Fillet Stored Under Refrigeration and Modified Atmosphere

This paper reports on the effect of carbon dioxide concentration on the formation of biogenic amines (BAs) in shredded cooked chicken breast fillet packed in modified atmosphere stored at 4C. The samples were grouped as follows: T1 (packed under atmospheric air), T2 (vacuum packaged), T3, T4, T5, T6 and T7 (packaged under modified atmosphere with 10, 30, 50, 70 and 90% CO2, respectively, and total volume completed with N2). Total viable count (TVC) and BA (tyramine, putrescine, cadaverine and spermidine) content were determined for 28 days. The results showed a gradual reduction in the growth rate of TVC as the concentration of CO2 increased. Also, in treatments with high CO2 contents, averaged concentrations of BAs detected were significantly smaller. In addition, increasing the concentration of CO2 caused a reduction in the amount of putrescine and cadaverine produced by bacteria. Amine quantification proved to be an adequate parameter to evaluate the quality index of this matrix. Practical Applications Biogenic amines (BAs) are toxic low-molecular-weight organic bases and are mainly produced by microbial decarboxylation of amino acids. They are frequently found in high concentrations in food and cannot be reduced by high-temperature treatments; modified atmosphere is an alternative technology for their reduction. The consumption of food containing large amounts of BAs can result in allergic reactions, characterized by difficulties in breathing, rash and hypertension. In consequence, it becomes important to monitor the levels of BAs in foods because of its relationship to public health and food safety.

Performance of broilers submitted to high CO2 levels during incubation combined with temperature fluctuations at late post-hatch

Incubation represents around 1/3 of the life cycle of broilers of modern strains; therefore, the appropriate management of this period is crucial to ensure the quality of the neonate. An experiment evaluated the effect of carbon dioxide concentrations during incubation on the live performance, heart morphology, and differential leukocyte count in the blood of broilers submitted to fluctuating temperatures between 35 and 42 days of age. In total, 2,520 fertile eggs were distributed according to a completely randomized design with four CO2 concentrations (4,000; 6,000; 8,000 and 10,000 ppm) during the first ten days of incubation, after which all eggs were incubated at the same CO2 level (4,000 ppm). After hatching, male chicks were placed in the experimental broiler houses, and at 35 days of age, 25 birds from each level of CO2 were separated and placed in cages to study the effect of cyclic temperature variations up to 42 days of age on their live performance, heterophil:lymphocyte ratio, and heart morphology. At 42 days of age, blood was collected for hematology and two birds per replicate were sacrificed and evaluated for ascites score and heart and liver relative weights. Heart morphology was assessed by analyzing digital images. In this experiment, hypercapnia during incubation and fluctuating temperatures during the growout did not affect mortality, ascites score, heart and liver relative weights, or heart characteristics (p>0.05). However, heterophill:lymphocyte ratio increased (p<0.05) with increasing carbon dioxide concentrations during incubation. It was concluded that high CO2 levels during incubation did not influence the resistance of broilers to fluctuating temperatures during the last week of age.

Kinetics of the gasification of a Rio Turbio coal under different pyrolysis temperatures

The kinetics of the gasification reaction of char with CO2 in a fix bed reactor was studied by gas chromatography. The char was produced by devolatilizing raw coal from Rio Turbio, Argentina in a drop tube furnace (DTF). Two chars were prepared and characterized for pyrolysis temperatures of 1123 and 1223K. The experimental conditions for chemical reaction rate control were obtained in the range of temperatures between 1098 and 1193K. Under those conditions the influence of gasification temperature and carbon dioxide concentration was analyzed. Similar values of activation energies were obtained for both chars, and only a slight decrease in reactivity was detected for the highest pyrolyzation temperature. Regarding the effect of carbon dioxide concentrations, no influence in the gasification rate was obtained for the char pyrolyzed at 1223K, whereas a reaction order of about 0.5 was obtained for CO2 concentrations below 30% for the other char. Two reaction models were applied that fairly fit the experimental data: the random pore model and the grain model. The reaction rate equations according to the different models were determined.

THE EFFECT OF MODIFIED ATMOSPHERE PACKAGING ON THE QUALITY AND SHELF LIFE OF FRANKFURTER TYPE‐SAUSAGES

ABSTRACT The effects of modified atmosphere packaging on the quality and shelf life of frankfurter‐type sausages, prepared exclusively from beef meat, were investigated. Sausages were packed under varying modified atmosphere conditions (30% CO2/70% N2; 70% CO2/30% N2; 100% CO2; 80% CO2/20% O2) and vacuum, and stored at 4C for 28 days. Lower pH values were observed in the samples packed under modified atmospheres compared to vacuum. Inhibition effect of carbon dioxide concentration on the oxidation was seen. Carbon dioxide caused microbial inhibition. The lowest total viable count was found in the samples packed under 100% CO2. It was concluded that modified atmosphere packaging had significant effect on the quality and shelf life of frankfurter‐type sausages compared to vacuum packaging. The most suitable atmosphere among the tested atmospheres was that with 70% CO2, 30% N2 atmosphere. The shelf life of sausages under this atmosphere was 28 days. PRACTICAL APPLICATIONSMeat and meat products are susceptible to spoilage. Several preservation techniques are used to extend their shelf life. Packaging of fresh meat is a common application to protect its quality. Modified atmosphere packaging (MAP) means to replace the air in a package of food with some different mixture of gases. The success in MAP is to choose the suitable gas combination, packaging system, package application and the package material. Proper gas combination to keep meat quality should be provided. Several studies have been performed to extent shelf life of pork sausages and local‐type sausages using modified atmosphere packaging technique. However there is no data on beef sausages. The results of this research will form the basis for further studies and also will be beneficial for industry.

Δ P index with different gas compositions for instantaneous outburst prediction in coal mines

In this study we measured the Δ P (initial speed of gas emission) index with different gas concentrations of carbon dioxide (pure CO 2, 90% CO 2+10% CH 4, 67% CO 2+33% CH 4, 50% CO 2+50% CH 4, 30% CO 2+10% CH 4 and pure CH 4) of coal samples from the No.2 coal seam in the Yaojie Coal Mine, Gansu province, China. The effect of carbon dioxide concentration, gas composition, coal strength and particle size of coal samples on the Δ P index was investigated. The experimental results show that with gas of various compositions, the Δ P value of three samples were clearly different. The Δ P index of coal samples A, B and C (0.2∼0.25 mm) were 4, 6 and 7 with pure CH 4 and 22, 30 and 21 when pure CH 4 was used. Carbon dioxide concentration affects the Δ P index markedly. The Δ P index increases with an increase in carbon dioxide concentration, especially for coal B. Hence, the Δ P index and K (another outburst index) values tested only with pure CH 4 for prediction of the danger of outburst is not accurate. It is important to determine the initial speed of gas emission given the gas composition of the coal seam to be tested for exact outburst prediction.

Volatile diffusion in silicate melts and its effects on melt inclusions

A compendium of diffusion measurements and their Arrhenius equations for water, carbon dioxide, sulfur, flu- orine, and chlorine in silicate melts similar in composition to natural igneous rocks is presented. Water diffusion in silicic melts is well studied and understood, however little data exists for melts of intermediate to basic com- positions. The data demonstrate that both the water concentration and the anhydrous melt composition affect the diffusion coefficient of water. Carbon dioxide diffusion appears only weakly dependent, at most, on the volatile- free melt composition and no effect of carbon dioxide concentration has been observed, although few experi- ments have been performed. Based upon one study, the addition of water to rhyolitic melts increases carbon dioxide diffusion by orders of magnitude to values similar to that of 6 wt% water. Sulfur diffusion in intermedi- ate to silicic melts depends upon the anhydrous melt composition and the water concentration. In water-bearing silicic melts sulfur diffuses 2 to 3 orders of magnitude slower than water. Chlorine diffusion is affected by both water concentration and anhydrous melt composition; its values are typically between those of water and sulfur. Information on fluorine diffusion is rare, but the volatile-free melt composition exerts a strong control on its dif- fusion. At the present time the diffusion of water, carbon dioxide, sulfur and chlorine can be estimated in silicic melts at magmatic temperatures. The diffusion of water and carbon dioxide in basic to intermediate melts is on- ly known at a limited set of temperatures and compositions. The diffusion data for rhyolitic melts at 800°C to- gether with a standard model for the enrichment of incompatible elements in front of growing crystals demon- strate that rapid crystal growth, greater than 10 −10 ms −1 , can significantly increase the volatile concentrations at the crystal-melt interface and that any of that melt trapped by the formation of melt inclusions may not be rep- resentative of the bulk melt. However, basaltic melt inclusions trapped at 1300°C are more likely to contain bulk melt concentrations of water and carbon dioxide.

Effect of carbon dioxide concentrations on asymmetric reduction of ketones with plant-cultured cells

Enantioselectivities in asymmetric reduction of ketones were controlled by atmospheric carbon dioxide concentrations: the reaction in high carbon dioxide concentrations under illumination of fluorescent light afforded the corresponding l-alcohol while that in low carbon dioxide concentrations in the presence of glucose under dark conditions gave the antipode, d-alcohol.

Phase equilibria in ternary (carbon dioxide + tetrahydrofuran + water) system in hydrate-forming region: Effects of carbon dioxide concentration and the occurrence of pseudo-retrograde hydrate phenomenon

In the present work, the three- and four-phase hydrate equilibria of (carbon dioxide (CO 2) + tetrahydrofuran (THF) + water) system are measured by using Cailletet equipment in the temperature and pressure range of (272 to 292) K and (1.0 to 7.5) MPa, respectively, at different CO 2 concentration. Throughout the study, the concentration of THF is kept constant at 5 mol% in the aqueous solution. In addition, the fluid phase transitions of L W–L V–V → L W–L V (bubble point) and L W–L V–V → L W–V (dew point) are determined when they are present in the ternary system. For comparison, the three-phase hydrate equilibria of binary (CO 2 + H 2O) are also measured. Experimental measurements show that the addition of THF as a hydrate promoter extends hydrate stability region by elevating the hydrate equilibrium temperature at a specified pressure. The three-phase equilibrium line H–L W–V is found to be independent of the overall concentration of CO 2. Contradictory, at higher pressure, the phase equilibria of the systems are significantly influenced by the overall concentration of CO 2 in the systems. A liquid–liquid phase split is observed at overall concentration of CO 2 as low as 3 mol% at elevated pressure. The region is bounded by the bubble-points line (L W–L V–V → L W–L V), dew points line (L W–L V–V → L W + V) and the four-phase equilibrium line (H + L W + L V + V). At higher overall concentration of CO 2 in the ternary system, experimental measurements show that pseudo-retrograde behaviour exists at pressure between (2.5 and 5) MPa at temperature of 290.8 K.