• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.167-174
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• 2013

Six kinds of sprout vegetables were applied three and six types of non-perforated breathable propylene films (NPB film) for individual and mixed modified atmosphere (MA) package condition at $10^{\circ}C$ on this study. As a tah tasai, kohlrabi, rape, chinese cabbage, red radish, broccoli sprouts were packaged by 20,000, 60,000, and 100,000 $cc{\cdot}m^{-2}{\cdot}day{\cdot}atm$ non-perforated breathable films for seven days storage. Mixed sprout vegetables were used 20,000 cc, 40,000 cc, 60,000 cc, 80,000 cc, and 100,000 $cc{\cdot}m^{-2}{\cdot}day{\cdot}atm$ non-perforated breathable films for seven days storage. Loss rate of fresh weight, changes of carbon dioxide, oxygen, and ethylene gas concentration were measured during the storage. Visual quality and off-flavor were rated by panel tests after seven days storage. Each sprout vegetable storage with film tests had been shown under the 0.5% fresh weight loss in every packaged films, and the 20,000cc NPB film package had been suitable atmosphere condition in the carbon dioxide and oxygen gas concentration. Appearance and off-odor of sprouts packaged with 20,000cc NPB film were shown better than other films because of the proper gas movement through the film to outside during the storage. Fresh weight loss of the mixed sprout vegetables had no difference among the NPB films for seven days storage. The 20,000 cc film had been resulted in that exchange rate of carbon dioxide and oxygen was highest cause of low film permeability than sprouts respiration. But the film is not good for storage because it has been made poor value of off-order even showed high visual quality from panel test after storage. 40,000 cc and 60,000 cc non-perforated breathable films were more suitable for mixed sprout vegetable storage at $10^{\circ}C$. These result suggested that 20,000 cc NPB film was good for single packaged sprout vegetable and 40,000 cc and 60,000 cc non-perforated breathable films were good for mixed packaged sprout vegetable.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.360-365
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• 2010

The effects of precooling treatments on the storability of chicon were investigated during modified atmosphere (MA) storage. The forced air cooling showed faster precooling rate that reduced the internal temperature of chicon to $2{\pm}1^{\circ}C$, and the precooling time of forced air cooling was 1/6 of room cooling. The half cooling time was 3 hr 21 min in room cooling and 1 hr 17 min in forced air cooling. Weight loss was less than 0.5% in all treatments both $5^{\circ}C$ and $10^{\circ}C$ MA storage and maintained higher in forced air cooling treatment. The concentration of carbon dioxide, oxygen, and ethylene of $50{\mu}m$ ceramic film packages were observed higher at $10^{\circ}C$ than $5^{\circ}C$. The precooling effect on respiration reduction was not shown at $5^{\circ}C$, but appeared that the gas concentration of precooling treatments showed less carbon dioxide and higher oxygen than non precooling treatment by 9 days after $10^{\circ}C$ storage. Ethylene concentration of precooling treatments showed lower than non precooling treatment until 3 days both $5^{\circ}C$ and $10^{\circ}C$ MA storage. Precooling showed the effect on maintaining visual quality of chicon both $5^{\circ}C$ and $10^{\circ}C$ MA storage. However, the forced air cooling that showed faster precooling rate did not appeared more precooling effect on the visual quality than room cooling because the fast air flow (6.0 m/sec) of forced air cooling hit directly on chicon outer leaves and might cause physical damage to chicon. Although the forced air cooling showed the effect on maintaining quality of chicon, but additional studies should be needed that investigated proper air flow rate and cooling box structure can prevent physical damage by air flow.

• Food Science and Preservation
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• v.10 no.1
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• pp.16-22
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• 2003

This study was conducted to find out effective MA (Modified Atmosphere) gas compositions on the oyster mushroom through statistical analysis of the respiration rate and MA storage for the various packaging materials. Under the various gas compositions, the oxygen consumption rate of oyster mushroom was from 28.9 to 161.4mgO$_2$/kg$.$hr and the carbon dioxide evolution rate was from 53.4 to 166.9 mgCO$_2$/kg$.$hr at 20$^{\circ}C$. The estimated MA condition of oyster mushroom were 2.5∼4.5%O$_2$and 11.5∼l3%CO$_2$by the RSREG(Response Surface Regression). The gas compositions of MA packaging are following that 0.03mm LDPE were 1.6∼3.0%O$_2$and 3.9∼5.3%CO$_2$,0.05mm LDPE were 1.2∼1.3%O$_2$and 9.0∼11.1%CO$_2$and Nylon+PE were 0.9∼1.2%O$_2$and 33.5∼39.6%CO$_2$. The weight loss increased at 0.03mm LDPE but has the lowest value at Nylon+PE. The hardness of pileus and stipe was decreased with storage periods. The $\Delta$E-value increased with storage period and seriously changed in early storage period at 12 and 20$^{\circ}C$. In the 0.05mm LDPE, the gas compositions of packaging were similar to estimated gas compositions from the RSREG and the storage quality was superior to the other packaging materials in weight loss, hardness, and color difference at 4, 12 and 20 $^{\circ}C$.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.401-409
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• 2021

This study aimed to estimate the photosynthetic capacity of tomato plants grown in a semi-closed greenhouse using temperature response models of plant photosynthesis by calculating the ribulose 1,5-bisphosphate carboxylase/oxygenase maximum carboxylation rate (V_cmax), maximum electron transport rate (J_max), thermal breakdown (high-temperature inhibition), and leaf respiration to predict the optimal conditions of the CO₂-controlled greenhouse, for maximizing the photosynthetic rate. Gas exchange measurements for the A-C_i curve response to CO₂ level with different light intensities {PAR (Photosynthetically Active Radiation) 200µmol·m^-2·s^-1 to 1500µmol·m^-2·s^-1} and leaf temperatures (20℃ to 35℃) were conducted with a portable infrared gas analyzer system. Arrhenius function, net CO₂ assimilation (A_n), thermal breakdown, and daylight leaf respiration (R_d) were also calculated using the modeling equation. Estimated J_max, A_n, Arrhenius function value, and thermal breakdown decreased in response to increased leaf temperature (> 30℃), and the optimum leaf temperature for the estimated J_max was 30℃. The CO₂ saturation point of the fifth leaf from the apical region was reached at 600ppm for 200 and 400µmol·m^-2·s^-1 of PAR, at 800ppm for 600 and 800µmol·m^-2·s^-1 of PAR, at 1000ppm for 1000µmol of PAR, and at 1500ppm for 1200 and 1500µmol·m^-2·s^-1 of PAR levels. The results suggest that the optimal conditions of CO₂ concentration can be determined, using the photosynthetic model equation, to improve the photosynthetic rates of fruit vegetables grown in greenhouses.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.198-221
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• 2021

After large-scale reforestation in the 1960s and 1970s, forests in Korea have gradually been aging. Net ecosystem CO₂ exchange of old-growth forests is theoretically near zero; however, it can be a CO₂ sink or source depending on the intervention of disturbance or management. In this study, we report the CO₂ budget dynamics of the Gwangneung deciduous old-growth forest (GDK) in Korea and examined the following two questions: (1) is the preserved GDK indeed CO₂ neutral as theoretically known? and (2) can we explain the dynamics of CO₂ budget by the common mechanisms reported in the literature? To answer, we analyzed the 15-year long CO₂ flux data measured by eddy covariance technique along with other biometeorological data at the KoFlux GDK site from 2006 to 2020. The results showed that (1) GDK switched back-and-forth between sink and source of CO₂ but averaged to be a week CO₂ source (and turning to a moderate CO₂ source for the recent five years) and (2) the interannual variability of solar radiation, growing season length, and leaf area index showed a positive correlation with that of gross primary production (GPP) (R²=0.32~0.45); whereas the interannual variability of both air and surface temperature was not significantly correlated with that of ecosystem respiration (RE). Furthermore, the machine learning-based model trained using the dataset of early monitoring period (first 10 years) failed to reproduce the observed interannual variations of GPP and RE for the recent five years. Biomass data analysis suggests that carbon emissions from coarse woody debris may have contributed partly to the conversion to a moderate CO₂ source. To properly understand and interpret the long-term CO₂ budget dynamics of GDK, new framework of analysis and modeling based on complex systems science is needed. Also, it is important to maintain the flux monitoring and data quality along with the monitoring of coarse woody debris and disturbances.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.267-277
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• 2023

This study is in order to the effect of 1-methlycyclopropene (1-MCP) treatment and film package as modified atmosphere packaging (MAP) on the changes in fruit quality factors of 'Daehong' peaches during cold storage. The concentrations of 1-MCP were treated at 1µL·L^-1 and 2µL·L^-1, and peaches in film package were stored for 28 days in cold storage at 5±1℃ and 85±5% RH. The fruits stored carton box were used as a control of MAP, and 1-MCP free fruits were used as the control of both packages. Rate of fresh weight loss during storage was not significantly different between groups with and without 1-MCP treatment, but was higher in the box package than in the MAP. The control group had a higher incidence of both gases with the 1-MCP treatment group showing statistically significantly low. Carbon dioxide in the package was lowered by about 12% compared to the non-treated group, and the ethylene concentration was maintained at 1µL·L^-1, showing a significance low compared to other treated groups. As the storage period elapsed, the firmness of 1-MCP and MAP treated fruits remained significant at 5-9% compared to the control group. Regardless of the packaging method Hunter a^* values of exocarp and mesocarp were significantly higher in fruit treated with 1-MCP 1µL·L^-1 treatment than in the control group, and anthocyanin was significantly higher in the fruit during the storage period, especially high in MAP. In summary, fruits of MAP group with 1-MCP 1µL·L^-1 had rate of lower respiration and ethylene production, and little changes in firmness, Hunter a^* values of exo-carp and meso-carp, and anthocyanin, which is considered the most suitable method for preserving postharvest quality of the peach cultivar during the storage.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.7
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• pp.1044-1049
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• 2014

This study was conducted in order to investigate whether the presence of light or different colors of light would influence the energy expenditure and behavior of broiler chickens. Eight 8-week-old broiler chickens were adapted to a respiration chamber (Length, 28.5 cm; Height, 38.5 cm; Width, 44.0 cm) for one week prior to the initiation of the experiment. In experiment 1, energy expenditure and behavior of the chickens were analyzed in the presence or absence of light for four days. Chickens were exposed to 6 cycles of 2 h light/2 h dark period per day. In experiment 2, the broiler chickens that had been used in experiment 1 were used to evaluate the effect of 4 different wavelength light-emitting diodes (LEDs) on the energy expenditure and behavior of broiler chickens. The LEDs used in this study had the following wavelength bands; white (control), red (618 to 635 nm), green (515 to 530 nm) and blue (450 to 470 nm). The chickens were randomly exposed to a 2-h LED light in a random and sequential order per day for 3 days. Oxygen consumption and carbon dioxide production of the chickens were recorded using an open-circuit calorimeter system, and energy expenditure was calculated based on the collected data. The behavior of the chickens was analyzed based on following categories i.e., resting, standing, and pecking, and closed-circuit television was used to record these behavioral postures. The analysis of data from experiment 1 showed that the energy expenditure was higher (p<0.001) in chickens under light condition compared with those under dark condition. The chickens spent more time with pecking during a light period, but they frequently exhibited resting during a dark period. Experiment 2 showed that there was no significant difference in terms of energy expenditure and behavior based on the color of light (white, red, green, and blue) to which the chickens were exposed. In conclusion, the energy expenditure and behavior of broiler chickens were found to be strongly affected by the presence of light. On the other hand, there was no discernible difference in their energy expenditure and behavior of broiler chickens exposed to the different LED lights.

• Journal of Radiation Protection and Research
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• v.33 no.4
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• pp.135-141
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• 2008

This paper describes a dynamic compartment model to predict the time-dependent $^{14}C$ activity in a plant as a result of a direct exposure to an amount of $^{14}CO_2$ for a short period of time, and experimental results for the model validation. In the model, the plant consists of two compartments of the body and ears, and five carbon fluxes between the compartments, which are the function of parameters relating to the growth and photosynthesis of a plant, are considered. Model predictions were made for an investigation into the effects of the exposure time, the elapsed exposure time, and the model parameters on the $^{14}C$ radioactivity of a plant. The present model converged to a region where the specific activity model is applicable when the elapsed time of the exposure was extended up to the harvest time of a plant. The $^{14}C$ activity of a plant was predicted to be the greatest when the exposure had happened in the period between the flowering and ears-maturity on account of the most vigorous photosynthesis rate for the period. Comparison of model predictions with the observed 14C radioactivity of rice plants showed that the present model could predict the $^{14}C$ radioactivity of the rice plants reasonably well.

• Food Science and Preservation
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• v.6 no.2
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• pp.153-160
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• 1999

This study was carried out to investigate the production of C$_2$H$_4$ and CO$_2$, and the change of flesh firmness and peel color in 'Fuji' apples during CA storage. ACC oxidase activity was more inhibited by the low O$_2$ concentration, and the low level of internal C$_2$H$_4$ in apples was maintained under the low O$_2$ conditions during 8 months storage. Especially, the level of internal C$_2$H$_4$ in apples was maintained below 1 ppm during storage under 1% O$_2$+1% CO$_2$ at 0$^{\circ}C$, and not much changed for 7 days in air at 20$^{\circ}C$ after storage. The influence of CO$_2$ on the C$_2$H$_4$ production was dependent on the O$_2$ concentration. Increasing of CO$_2$ concentration with 3% O$_2$ decreased the C$_2$H$_4$ Production during storage, but that with 1% O$_2$increased. Internal C$_2$H$_4$ concentration and the rate of CO$_2$ evolution in apples showed the close correlation. Internal CO$_2$ concentration of apples was positively related to the rate of CO$_2$ evolution and maintained the lower level in 1% O$_2$+1% CO$_2$ than the other conditions during storage but nu different in the increment after storage. The relationship between C$_2$H$_4$ and CO$_2$ production was exhibited in CA and the short-term air stored apples, but not in the long-term air stored apples. Loss of flesh firmness and green color in apples was more less in storage condition retarded effectively the production of C$_2$H$_4$ and CO$_2$.

• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.376-381
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• 1992

In order to study the effect of modified atmosphere storage on extending shelf life of mushrooms, oyster mushroom and Shiitake were wrapped with polyethylene film (PE, $50\;{\mu}m$), and stored at $0.5^{\circ}C$. Mushrooms packed with conventional hardboard box (4kg) lost marketability within $5{\sim}6$ days due to weight loss, shrinkage, browning, spore formation and/or mycellium growth. PE-packing could prevent or retard the deterioration of the mushrooms in the aspects of appearance, texture, discoloration, and microbial contamination. This situation can be best characterized by the reduced respiration rate resulted from the elevated level of carbon dioxide and the reduced level of oxygen in the bag. Although the appearance of the oyster mushroom was maintained for one month, its shelf life was limited to 15 days because of tissue softening. Discoloration of the pileus of shiitake mushroom appears to be the most important factor to determine its marketability. For example, extension of shelf life of Dongo was limited to 15 days, principally due to the browning of the pileus. Shelf life of Hawgo whose color of the pileus changed little over the experimental period, however, could be extened to more than one month.