• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.7-12
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• 2018

This study was conducted to determine effects of precooling and storage methods on asparagus spears' quality such as changes of fresh weight and color during simulated export distribution. Two types of precooling methods, air cooling and hydrocooling, were applied prior to packaging by comparing with no precooling as a control. Asparagus spears were packed with oxygen transmission rate (OTR) film for modified atmosphere packaging (MAP) and perforated (PF) film for a conventional packaging. All treatments were stored at $8^{\circ}C$ for 20 hours, and subsequently at $4^{\circ}C$ by final storage day, which is simulated distribution temperature condition from Yanggu, Korea to Shimonoseki, Japan. The half cooling time was 12 minutes for air cooling and 15 seconds for the hydrocooling, indicating precooling process of asparagus spears faster with the hydrocooling. Rates of respiration and ethylene production were lowest with hydrocooling. Fresh weight loss was higher, approximately 11%, at the control condition in conventional storage, compared with the MAP, less than 0.5%. Carbon dioxide and oxygen content in the MAP was in the permissible ranges for asparagus spears under recommended CA/MA conditions under both the air cooling and hydrocooling. Ethylene content in the film package was lower with the precooling treatment. Firmness of stems was lowest with the hydrocooling prior to the MAP. Visual quality, off-odor, and hue angle value were best with hydrocooling prior to the MAP. In conclusion, the combination of hydrocooling with the MAP is effective in preserving quality during the export distribution process.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.60-64
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• 2014

These studies were conducted to identify the effects of non-perforated breathable package film on storability at $1^{\circ}C$, $8^{\circ}C$, and $20^{\circ}C$ storage of 'Fuji' apples. The fresh weight loss rate was less than 2.0% in all non-perforated breathable films at three different storage periods and temperatures, $1^{\circ}C$; 210 days, $8^{\circ}C$; 75 days, and $20^{\circ}C$; 30 days except for the perforated film. 1,300 cc ($1^{\circ}C$), 5,000 cc ($8^{\circ}C$), and 10,000 cc ($20^{\circ}C$) films were closed at the optimum MA storage condition by carbon dioxide and oxygen concentration. Ethylene concentration was lowest at the 40,000 cc film in every temperatures during storage. The 1,300 cc film established higher result in soluble solid and vitamin C content than any other films at $1^{\circ}C$, also showed higher in visual quality by panel test. The 5,000 cc film had the best results on soluble solid and off-flavor in $8^{\circ}C$. In the $20^{\circ}C$ storage after 30 days of treatment the 10,000 cc film had highest firmness and visual quality. Following these results, it come to conclusion the suitable type of non-perforated breathable film such as 1,300 cc at $1^{\circ}C$, 5,000 cc at $8^{\circ}C$, and 10,000 cc at $20^{\circ}C$ for MA storage in 'Fuji' apples.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.1-9
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• 2020

Magnesium silicate minerals such as serpentine [Mg₃Si₂O₅(OH)₄] have a high potential for the sequestration of CO₂; thus, their reactivity toward dissolution under CO₂-free and CO₂-containing conditions in acidic solvents is a critical process with respect to their carbonation reactions. To examine the carbonation efficiency and dissolution mechanism of serpentine, hydrothermal treatment was performed to the starting material via a modified direct aqueous carbonation process at 100 and 150℃. The serpentine dissolution experiments were conducted in H₂SO₄ solution with concentration range of 0.3-1 M and at a CO₂ partial pressure of 3 MPa. The initial pH of the solution was adjusted to 13 for the carbonation process. Under CO₂-free and CO₂-containing conditions, the carbonation efficiency increased in proportion to the concentration of H₂SO₄ and the reaction temperature. The leaching rate under CO₂-containing conditions was higher than that under CO₂-free conditions. This suggests that shows the presence of CO₂ affects the carbonation reaction. The leaching and carbonation efficiencies at 150℃ in 1 M H₂SO₄ solution under CO₂-containing conditions were 85 and 84%, respectively. The dissolution rate of Mg was higher than that of Si, such that the Mg : Si ratio of the reacted serpentine decreased from the inner part (approximately 1.5) to the outer part (less than 0.1). The resultant silica-rich layer of the reaction product ultimately changed through the Mg-depleted skeletal phase and the pseudo-serpentine phase to the amorphous silica phase. A passivating silica layer was not observed on the outer surface of the reacted serpentine.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.175-181
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• 2013

These studies were identified the effect of four types of non-perforated breathable (NPB) packing film and three sizes on storage ability of fresh-cut for ready to eat packaging at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days storage in Salicornia herbacea. The fresh weight loss was less than 2% in every films at $5^{\circ}C$ condition after 25 days storage, and the $10^{\circ}C$ also had same result on 15 days storage except 100,000 cc NPB film. Compare with storage after 15 days, storage condition at $5^{\circ}C$ had shown better result under the 1% fresh weight loss rate. The 5,000 cc and $5^{\circ}C$ condition had been shown the characteristics of MA packaging in carbon dioxide and oxygen concentrations. The ethylene concentration in vacuum film was higher 10 to 100 times than in NPB film treatments during storage. But ethylene concentration was not statistically significant differences among size treatments. Every conditions had been measured the anti-oxidant activity by DPPH method after storage at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days. S. herbacea at $5^{\circ}C$ had been more than twice of activity compare with that at $10^{\circ}C$. 100,000 cc NPB film had been higher contents of anti-oxidant activity at $5^{\circ}C$ and $10^{\circ}C$. As the fresh-cut sizes, 3 cm and 5 cm sizes had changed depending on film types but 10 cm were not effected by the film types in the DPPH activity. When panel test had been tried to measure the visual quality and off-flavor after storage, $5^{\circ}C$ with a filme of 5,000 cc treatment had established higher value than other treated conditions. As these results, it's may be suggested that the $5^{\circ}C$ with 5,000 cc non-perforated breathable film for MA storage in Salicornia herbacea at fresh cut distribution system. Fresh cut size 10 cm with 100,000 cc NPB film also had the good quality for 15 dyas storage at $10^{\circ}C$, and this result can be applied for short term distribution system in Korea.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.36-43
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• 2024

Fishing net waste (FNW) constitutes over half of all marine plastic waste and is a major contributor to the degradation of marine ecosystems. While current treatment options for FNW include incineration, landfilling, and mechanical recycling, these methods often result in low-value products and pollutant emissions. Importantly, FNWs, comprised of plastic polymers, can be converted into valuable resources like syngas and pyrolysis oil through pyrolysis. Thus, this study presents a process for generating high-purity hydrogen (H₂) by catalytically pyrolyzing FNW in a CO₂ environment. The proposed process comprises of three stages: First, the pretreated FNW undergoes Ni/SiO₂ catalytic pyrolysis under CO₂ conditions to produce syngas and pyrolysis oil. Second, the produced pyrolysis oil is incinerated and repurposed as an energy source for the pyrolysis reaction. Lastly, the syngas is transformed into high-purity H₂ via the Water-Gas-Shift (WGS) reaction and Pressure Swing Adsorption (PSA). This study compares the results of the proposed process with those of traditional pyrolysis conducted under N₂ conditions. Simulation results show that pyrolyzing 500 kg/h of FNW produced 2.933 kmol/h of high-purity H₂ under N₂ conditions and 3.605 kmol/h of high-purity H₂ under CO₂ conditions. Furthermore, pyrolysis under CO₂ conditions improved CO production, increasing H₂ output. Additionally, the CO₂ emissions were reduced by 89.8% compared to N₂ conditions due to the capture and utilization of CO₂ released during the process. Therefore, the proposed process under CO₂ conditions can efficiently recycle FNW and generate eco-friendly hydrogen product.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.227-232
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• 2011

The processing techniques are need to use the non-marketable paprika fruit because paprika that is difficult crop for cultivation and produced easily non-marketable fruits, such as physiological disorder fruit, malformed fruit, and small size fruit. This study was carried out to investigate the proper active modified atmosphere packaging (MAP) condition for enhancing the storability of fresh-cut paprika fruit. The fresh-cut paprika (cv 'Score', seminis) put into $7cm{\times}0.7cm$ size and packed them in 20 g bags. The active MAP and vacuum treated paprika fruits were packaged with LLDPE/Nylon, EVOH, Tie film, and injected partial pressures of $CO_2$ and $O_2$, and $N_2$ in the packages immediately after sealing to treat active MAP. The ratio of $CO_2$, $O_2$, and $N_2$ of active MAP conditions were 0 : 20 : 80 (air), 5 : 5 : 90, 30 : 10 : 60, 10 : 70 : 20 and vacuum treatment did not contain any gas. The passive packaging treated paprika packaged with $40{\mu}m$ ceramic film. After 7 days of storage at $9^{\circ}C$, the fresh weight decreased less than 2% in all treatments, and showed lower in 5 : 5 : 90 ($CO_2:O_2:N_2$) active-MAP treatment and higher in vacuum treatment than other treatments. The $CO_2$ and $O_2$ concentration in packages did not change remarkably in active-MA treatments except 30 : 10 : 60 active-MAP treatment that showed sharply decreased $O_2$, concentration and increased $CO_2$ concentration at $1^{st}$ day of storage at $9^{\circ}C$. The ethylene concentration in package was the highest in 30 : 10 : 60 active-MAP treatment and the lowest in the passive MAP treatment that packaged with gas permeable film during $9^{\circ}C$ storage for 7 days. The 30 : 10 : 60 active-MAP treatments were not proper condition to storage fresh-cut paprika. The visual quality was maintained higher in 0 : 20 : 80 (air), 5 : 5 : 90, and 10 : 70 : 20 active MAP treatments and passive MAP treatment than others and the firmness, off-odor, and electrolyte leakage was investigated at 7th day of storage at $9^{\circ}C$. The 5 : 5 : 90 and 10 : 70 : 20 active-MAP treatment showed higher firmness and lower off-odor than other treatments after $7^{th}$ day of storage at $9^{\circ}C$. In addition, the electrolyte leakage was reduced less than 20% at 0 : 20 : 80 (air), 5 : 5 : 90, 10 : 70 : 20, and passive MA treatments. Therefore, 10 : 70 : 20 ($CO_2:O_2:N_2$) and 0 : 20 : 80 (air) might be recommended for proper active MAP conditions.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.1-8
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• 2022

We investigated the effects of stunning methods and gas treatments during slaughter on the quality characteristics of chicken breast and small intestine. Broilers (Ross 308) were stunned and slaughtered using halal, CO₂, or N₂ gas stunning methods (for 10 birds). After slaughter, the pH, proximate composition, color, water-holding capacity, cooking loss, and shear force of chicken breast muscle and small intestine were determined. Compared with the halal treatment, CO₂ treatment resulted in higher pH and lower cooking loss (P<0.05), and the pH, color, and shear force of chicken breast muscle with N₂ treatment were similar to those of the halal treatment (P>0.05). Compared with the halal treatment, the gas treatments resulted in lower pH and lightness and higher redness, yellowness, thickness, and shear force of the small intestine (P<0.05). However, compared with the CO₂ treatment, the N₂ treatment resulted in lower pH, redness, and yellowness, and higher lightness, thickness, and shear force. Overall, compared with the halal method, our results suggest that the use of N₂ gas suppresses the discoloration and deterioration of the texture of chicken meat and small intestine caused by CO₂ gas treatment in the gas stunning method.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.180-184
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• 2018

This study was conducted to examine the effect OTR film type on the quality of garden cress (Lepidium sativum L.) baby leaf during MA storage. Garden cress harvested at baby leaf size of 10cm plant height packed with 1,300 cc, 10,000 cc, 20,000 cc, 40,000 cc, and $80,000cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ OTR (oxygen transmission rate) films and MP (micro-perforated) film, and then stored at $8^{\circ}C$ for 10 days. All of the OTR film treatments showed a decrease of 0.5% fresh weight until the storage end date and a 1.3% decrease in the MP film treatment. The oxygen concentration in the packaging during storage was maintained at 18% or more in 20,000 cc, 40,000 cc, and 80,000 cc OTR film treatments, while the 1,300 cc OTR film treatment decreased to 11% at the storage end date. And the concentration of carbon dioxide was steadily increased in the 1,300 cc and 10,000 cc OTR film treatments to show the levels of 4.5% and 3.4%, respectively, and the other OTR film treatments showed a concentration of less than 1%. Ethylene concentration in the package was maintained at the highest level of $3-5{\mu}L{\cdot}L^{-1}$ in the 1,300 cc treatment during the storage period. The lowest odor and the highest quality of appearance were observed in the 1,300 cc treatment, but the MP film treatment and the other OTR treatments lost marketable quality due to yellowing. The color of garden cress baby leaf was changed the lowest in 1,300 cc treatment that showed the highest chlorophyll content and Hue angle value, lowest $b^*$ value, present of yellowing at end of storage date. Therefore, 1,300 cc treatment which was most effective for yellowing and odor suppression during storage is considered to be suitable for packaging of garden cress baby leaf.

• Food Science and Preservation
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• v.23 no.1
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• pp.12-19
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• 2016

This study was conducted to determine $CO_2$ treatment condition to extend the shelf-life of 'Seolhyang' strawberry. Fresh strawberries with red color on 80% of the fruit surface were harvested. The samples at two different stages (on the $1^{st}$ and $3^{rd}$ day after harvest) were placed in a gas-tight chamber with 0, 5, 15, or 30% $CO_2$ concentration for 3 hours at $4^{\circ}C$. Then, the strawberry samples were immediately packaged in a PET tray and stored at $4^{\circ}C$. The carbon dioxide treatment was effective in maintaining the quality of 'Seolhyang' strawberries treated on the $1^{st}$ day after harvest. These samples had higher firmness, lower redness, softening index, and decay rate compared to samples treated on the $3^{rd}$ day after harvest. Treatment with both 15 and 30% of $CO_2$ concentration on the $1^{st}$ day after harvest induced an increase of firmness of 'Seolhyang' strawberry after the treatment. Samples treated with 15 and 30% $CO_2$ the $1^{st}$ day after harvest maintained quality for 10 days. However, samples treated with $CO_2$ on the $3^{rd}$ day after harvest lost marketability at 10 days of storage. At the atmosphere containing 30% $CO_2$ on the $1^{st}$ day after harvest was most effective in reducing decay rate and fruit softening, and maintaining bright red color of strawberries among different $CO_2$ concentrations. Therefore, a 30% $CO_2$ treatment within one day after harvest can be a practical postharvest technology to extend shelf-life of 'Seolhyang' strawberry.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.128-136
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• 1991

This experiment was conducted to evaluate the effect of plant growth regulators, dichlorprop and MCPB on the reduced effect of fruit drop and fruit quality before and after storage in apples. Dichlorprop was tested with dilution of 1000 at 30, 40, 50 days before harvesting, and MCPB with dilution of 4000 at 15, 25, 35 days before harvesting. The results are summarized as follows : Percentage of fruit drop was appeared to the notable reduction as compared with the untreated control when regulators was applied with dilution of 1000 at 30 days before harvesting by dichlorprop and with dilution of 4000 at 35 days before harvesting by MCPB. Degree of fruit colour showed to the remarkable promotion at all the treatment of 30, 40, 50 days before harvesting by dichlorprop as compared with the untreated control. Sugar contents in flesh was increased a little at the treatment of 30 days before harvesting by dichlorprop, but acid contents in flesh was reduced at all the treatment of 30, 40, 50 days before harvesting by dichloroprop and at 15, 25, 35 days before harvesting by MCPB. Passed firmness of fruit after storage was maintained at the treatment with dilution of 4000 at 35 days before harvesting. Therefore, it was repressed a softening of fruit, but by dichlorprop treatment at 30, 40, 50 days before harvesting, fruit firmmess was appeared to reduce according to the passage of storage period. Amount of ethylene evolution after storage was showed to reduce at all the treatment by early treated time of dichoroprop and MCPB, but carbon dioxide increased at treatment conditions such as the front. Accordingly, these relationship showed to be contrary each other.