• Korean Journal of Food Science and Technology
• /
• v.34 no.6
• /
• pp.1036-1042
• /
• 2002

During storage at $25^{\circ}C$, the effect of gas absorbents, such as carbon dioxide scavenger, ethylene absorber, and their combinations, on respiration characteristics and quality attributes of mature-green Mume fruits packaged in $30\;{\mu}m$ low density polyethylene (LDPE) film was examined. Changes in quality attributes of the fruits were observed in terms of weight loss, titratable acidity, pH, fish firmness, color, water-soluble solid, and chlorophyll contents. In the presence of ethylene absorber $(KMnO_4)$, the physiological injury was remarkably suppressed, and there was no significant injury in Mume fruits at $25^{\circ}C$ for 10 days. Yellowing and softening were also noticeably reduced by the combination of plastic film packaging and inclusion of ethylene absorber. The respiration rate was slower in fruits sealed with ethylene absorber than in those with absorbent-free packaging. Using ethylene absorber, levels of oxygen and carbon dioxide were maintained at 2-3 and 7-8%, respectively, during storage at $25^{\circ}C$ for 10 days. The addition of carbon dioxide scavenger $(Ca(OH)_2)$, negatively affected the quality attributes and respiration characteristics of the fruits. Overall results showed that ethylene removal by gas absorbent in the film packages significantly prolonged the shelf life of the fruits at ambient temperature.

• Journal of Climate Change Research
• /
• v.8 no.3
• /
• pp.257-264
• /
• 2017

Carbon capture and storage (CCS) technology has been suggested as an ultimate strategy for mitigating climate change. However, potential leakage of $CO_2$ from the CCS facilities could lead to serious damage to environment. Plants can be a bio-indicator for $CO_2$ leakage as a cost-effective way, although plants' responses vary with plant species. In this study, a greenhouse experiment was conducted to investigate the relation between the $CO_2$ tolerance of corn species and the initial physiological responses to the elevated soil $CO_2$ concentration. Treatment groups included CI (99.99% $CO_2$ gas injection) and BI (no gas injection). Mean soil $CO_2$ concentration for the CI treatment was 19.5~39.4%, and mean $O_2$ concentration was 6.6~18.4%. The soil gas concentrations in the BI treatment were at the ambient levels. In the CI treatment, chlorophyll content was not decreased until the $13^{th}$ day of the $CO_2$ injection. On the $15^{th}$ day, leaf starch content and stomatal conductance were increased by 89% and 25% in the CI treatment compared to the BI treatment, respectively. This might be due to the compensatory reaction of corn to avoid high soil $CO_2$ stress. However, the prolonged $CO_2$ injection decreased chlorophyll content after 13 days. After $CO_2$ injection, plant biomass was reduced by 25% in the CI treatment compared to the BI treatment. Due to the inhibited root growth, leaf phosphorous and potassium contents were decreased by 54% on average in the CI treatment. This study indicates that corn has a high tolerance to soil $CO_2$ concentration of 30% for 2 weeks by its compensatory reactions such as an maintenance of chlorophyll content and an increase in stomatal conductance.

• Journal of Korea Water Resources Association
• /
• v.54 no.8
• /
• pp.567-576
• /
• 2021

Climate change threatens the security of domestic water resources in South Korea. To overcome the potential water shortage, various approaches are being studied by alterning the operation of dams or by integrated operation of multiple dams and reservoirs. However, most of the related researches were developed and applied for multi-purpose dams, and few studies were conducted for the hydropower dams. The main purpose of the hydropower dam is to generate electric energy; however, the potential water shortage due to prolonged droughts brings the idea to supply water from the hydropower dam in the basin. To that end, it is required to estimate the water supply ability of the hydropower dams. In this study, we proposed a methodology to classify the hydropower dam into a "storage-type" and "run-of-river type" dam. The proposed approach was demonstrated using the hydropower dams located in North-han River basin. The results of this study are expected to contribute for further analysis of the hydropower dams, such as evaluation of water supply capacity and drought mitigation purpose operation of the hydropower dams.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.4
• /
• pp.619-624
• /
• 2016

Chlorine dioxide ($ClO_2$) gas treatment (75 ppmv, 30 min) has been suggested to improve the microbial safety of postharvest paprika in a previous study. Based on these results, in this study, an additional combined treatment using low-concentration $ClO_2$ gas-generating sticks (3 ppmv) in paprika samples during storage was carried out at $8^{\circ}C$ and 90% relative humidity to further enhance the quality and reduce the decay rate of paprika for the purpose of lengthy storage. After the combined treatment, the initial populations of total aerobic bacteria as well as yeast and molds in the paprika samples decreased by 3.04 and 2.70 log CFU/g, respectively, compared with those of the control samples, and this microbial inactivation was maintained by the low-concentration $ClO_2$ gas-generating sticks during storage. In particular, the decay rate of samples with combined treatment was significantly lower than that of the control. Vitamin C content, hardness, and color quality parameters of paprika samples were not altered by treatment, while weight loss of the samples treated with the combined $ClO_2$ gas was lower than that of the control during storage. These results indicate that the combination of two different $ClO_2$ gas treatments is effective for retaining the quality of paprika during prolonged storage.

• Korean journal of food and cookery science
• /
• v.14 no.1
• /
• pp.9-15
• /
• 1998

The inhibitory effect of clove (Eugenia caryophyllata Thumb) on the growth of Escherichia coli 0157:H7 was determined. Tryptic soy broth (TSB) containing 0∼0.5% (w/v) of clove was inoculated with 10/sup/5∼10/sup/7 CFU/ml of E. coli and incubated at 5 different temperature (35, 5, -20, 50 and $55^{\circ}C$). The growth of E. coli was not inhibited at 0.1% clove and growth occured at 0.3% after a prolonged lag period while viable cells of E. coli decreased at 0.5% clove during storage at $35^{\circ}C$. During 32 days of refrigerated storage at $5^{\circ}C$, survivors of E. coli were decreased with the progress of time and increasing clove concentration. At the presence of 0.3 or 0.4% clove, bacterial cells were dead at the end of refrigerated storage. During frozen storage at -$20^{\circ}C$, survivors of E. coli at the presence of 0∼0.4% clove were decreased 2.9∼4.07 log cycles for 4 days of early period and then decreased 1.0∼2.1 log cycles through the frozen storage. There were small changes in populations of E. coli in TSB between different concentrations of clove during frozen storage. The D-values for E. coli at $50^{\circ}C$ were 105.26, 22.47, 13.76, 11.14 and 10.17 min at clove 0, 0.1, 0.2, 0.3, 0.4%, respectively. The D-values for E. coli at $55^{\circ}C$ were 10.75, 8.95, 7.40, 5.96 and 4.96 min at clove 0, 0.1, 0.2, 0.3, 0.4%, respectively. Antibacterial activity of clove against E. coli was more effective at $50^{\circ}C$ than at $55^{\circ}C$.

• Food Science and Preservation
• /
• v.16 no.2
• /
• pp.166-171
• /
• 2009

The effects of vacuum precooling(VP) on the shelf-life of polyethylene film(PE) packaged King oyster mushrooms(Pleurotus eryngii) during storage at $-1^{\circ}C$ were investigated. VP was conducted below $0^{\circ}C$ in a $-1^{\circ}C$ cold chamber of 40 minutes, and mushrooms were stored for 30 days in batches of 1kg. The weight loss of the VP-treated mushroom was slightly lower than that of control. The $O_2$ concentrations of VP-treated mushroos, within 4 days of storage, were 2.44-14.50 %/kg-package/hr, thus higher than control values(2.01-8.19%/kg-package/hr). $CO_2$ generation of VP-treated mushrooms, again within 4 days of storage, was 0.47%/kg-package/hr, thus lower than that of controls(0.58%/kg-package/hr). The $CO_2/O_2$ ratio peaked on day 4 of storage in the control group, tbut no such peak was observed in VP-treated mushrooms. In the VP-treated fungi, lightness was higher, and redness and yellowness lower, than in controls, at all storage times.. In VP-treated mushrooms, strength, hardness and chewiness were significantly higher than in controls, but there were no significant differemces in springiness or cohesiveness. Softening and breakdown of under-cap wrinkles were observed in control mushrooms stored for 30 days, but occurred to a lesser extent in VP-treated fungi. Stipe reticulum tissue vessels in the 30 day-stored VP-treated mushrooms were relatively well-defined and clear, but were softer and diffuse in the control fungi. The results thus confirmed that VP after harvest enhanced mushroom shelf-life and PE packaging prolonged storage time. The data will have industrial applications.

• Korean Journal of Food Science and Technology
• /
• v.30 no.4
• /
• pp.871-876
• /
• 1998

'Yeobong' strawberries were stored at $2^{\circ}C$ under controlled atmosphere (CA) containing the combinations of $O_2{\;}(3.8%)$ and $CO_2{\;}(10,{\;}15,{\;}20%)$ and air as control. Atmospheres of $3%{\;}O_2+15%{\;}CO_2$ and $8%{\;}O_2+15%{\;}CO_2$ reduced respiration and ethylene production rates. Fruits kept under CA conditions of 10% and 15% $CO_2$ were harder than those stored under 20% $CO_2$ and air. The CA conditions of 10% or 15% $CO_2$ maintained approximately 80% of vitamin C for 24 days. Redness were increased and then decreased, but the changing trends were not clear among the storage conditions. Anthocyanin contents in $3%{\;}O_2+15%{\;}CO_2$ and $8%{\;}O_2+15%{\;}CO_2$ were slightly increased for 16 days and then decreased thereafter, while anthocyanin content in air was rapidly increased for 8 days. After 16 days of storage, off-flavor were perceived in all CA storage. And strawberries stored in 20% $CO_2$ conditions were unacceptable after 20 days. The 20% $CO_2$ significantly affected off-flavor of strawberries, but there was no significant difference between 10% $CO_2$ and 15% $CO_2$ conditions. Ethanol which is in relation to off-flavor was higher with elevated $CO_2$ levels. Although CA conditions under $3%{\;}O_2+15%{\;}CO_2$ was effective in delaying the quality changes, there was high ethanol content compared to $8%{\;}O_2+15%{\;}CO_2$ condition. Strawberry kept under $8%{\;}O_2+15%{\;}CO_2$ was maintained the shelf-life for 24 days and the condition prolonged more $4{\sim}8$ days and 12 days than the other CA conditions and air, resectively.

• Journal of Food Hygiene and Safety
• /
• v.14 no.4
• /
• pp.422-427
• /
• 1999

Antimicrobial activity of Korean leek was effective on Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, E. coli O157:H7, Pseudomonas fluorescens, Pichia membranaefaciens. Extract from raw Korean leek and that from frozen one showed antimicrobial activity; in contrast, extract stored frozen condition or extract from blanched one lost antimicrobial activity. Filtration, centrifugation, and vacuum concentration did not affect antimicrobial activity of the leek, nor did the changes in storage pHs. Addition of ground leek to soy milk, soy curd, and broth for cold noodle resulted in the prolonged shelf life by significantly reducing the number of viable cells.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.3
• /
• pp.436-445
• /
• 2020

Objective: Ensiling is a simple and effective method for long-term preservation; however, less information exists about the ensilability characteristics of garlic stalk (GS). Therefore, the objectives were to examine the ensiling feasibility of GS. Methods: The GS was ensiled alone or inoculated with Lactobacillus plantarum KU5 in the presence or absence of 5% molasses and ensiled for 7, 14, and 28 d. As an alternative storage method, GS was co-ensiled with wet citrus pulp (CP) at different proportions (GS:CP: 70:30, 60:40, 50:50, and 40:60). Analysis was made on physicochemical, fermentative, and nutritional parameters. Results: The GS was found to be a biomass which is difficult to ensile. A combination of microbial inoculant and molasses was successful in the improvement of the silage fermentation quality of GS. Co-ensiling of GS with wet CP at the mixing ratio of 50:50 provided the most desirable silage fermentation parameters, including the substantial lactic acid formation, low final pH, minor effluent loss, and the more favorable organoleptic properties. Conclusion: Co-ensiling GS with CP appears to be a simple and viable method of conservation, enabling the more efficient utilization of these by-product resources over a prolonged period.

• Journal of Chest Surgery
• /
• v.29 no.10
• /
• pp.1066-1075
• /
• 1996

To compare the efficacy of cardiac preservation, we examined purine metabolites during 24 hours of cold storage($0^{\circ}C$) of the Korean ongrel dog hearts after using three different types of cardioplegic solutions. The hypothermic arrest with total cardiopulmonAry bypass method was employed in 51. Thomas solution(575) and blood cardioplegic solution(BCPS) preservation cases. Specimens were analyzed for levels of adenine nucleotides and their precursors by high performance liquid chromatography. The ATP content in the UW(University of Wisconsin) solution group tends to be higher than that of the combined hypothermic arrest group(575 and BCPS groups) after 2,4,8, and 12 hours of preservation respectively, but there were no significant differences between 575 and BCPS groups. The ADP contents in the UWS and BCPS groups were higher than that of the 575 group at 4,8, 12, and 24 hours, but the difference was not statistically significant between UWS and BCPS groups. The AMP contents did not change significantly in the three groups. The adenosine, Inosine, and hypoxanthine concentrations increased progressively, but the lev l of xanthine was very low in the three groups.