• Korean Journal of Food Science and Technology
• /
• v.26 no.4
• /
• pp.382-388
• /
• 1994

Because of its restrictive harvest from spring to summer, It is necessary to preserve raw ascidians, Halocynthia roretzi, for the purpose of processing regardless of season. We evaluated low Temperature tolerance of ascidian and conditions for cold storage to secure the quality of the stock. To retard the browning of meat rapidly occurred after sucking, ascidians were blanched for 10 seconds in 10% boiling salt solution or dipped for 60 seconds in 0.2% $NaHSO_3$ solution, respectively. The samples were stored in ice, at $-17^{\circ}C$ or $-35^{\circ}C$ for 85 days, respectively. Changes in VBN, glycogen, brown pigment formation, total carotenoid, nucleotides and their related compounds during the storage were determined, and sensory evaluation of quality was also practiced. VBN and brown pigment formation were rapidly increased. Glycogen was gradually decreased and then not detectable after 85 days in case of ice storage. Lipophilic brown pigment was higher than hydrophilic and rapidly increased during storage. The result of sensory evaluation showed that the ascidian treated in 0.2% $NaHSO_3$ was good for 85 days of storage at $-35^{\circ}C$ . Judging from the results of chemical experiment and sensory evaluation, the quality of ascidian treated in 0.2% $NaHSO_3$ and stored at $-35^{\circ}C$ was better than that of other samples.

• Journal of Korean Society of Forest Science
• /
• v.94 no.6
• /
• pp.370-376
• /
• 2005

Sarcodon aspratus is well known as a natural edible mushroom and a symbiotic mycorrhizal fungus with oaks. This study was conducted to clarify the effects of environmental conditions on the fruiting of S. aspratus on the hillslope of Wolak Mt., Jecheon city, Chungbuk, South Korea. Soil moisture and soil temperature in S. aspratus colony were measured hourly and compared with those in the non-colony soil. The mean soil moisture during the mushroom development was 14.3% in the colony soil and 16.4% in the non-colony soil. The S. aspratus colony soils showed 2.1% less soil moisture. The mean soil temperature was $16.8^{\circ}C$ in the colony soil and $16.5^{\circ}C$ in the non-colony soil. The S. asprauts colony soils showed slightly higher temperature. It is considered that more soil water was consumed and more energy was emitted during the mycelial elongation and the mushroom development. The development of S. aspratus seems similar to that of T. matsutake which is known to be considerably affected by soil moisture, daily maximum air temperature, daily minimum air temperature and daily minimum soil temperature. The season of S. aspratus development ranges from the end of August to the beginning of October. And Ellino phenomenon and its unusual change in the weather seems to affect primodia and fruiting body development. Especially if daily minimum soil temperature continues to become higher than $20^{\circ}C$, the damage of primodia and its fruiting body was frequently observed in the field plots during the last few years recently.

• Journal of the Korean Society of Safety
• /
• v.7 no.2
• /
• pp.63-70
• /
• 1992

The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass％) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass％). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume％) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

• Korean journal of applied entomology
• /
• v.50 no.4
• /
• pp.373-378
• /
• 2011

The striped fruit fly, Bactrocera scutellata, damages pumpkin and other cucurbitaceous plants. The developmental period of each stage was measured at seven constant temperatures (15, 18, 21, 24, 27, 30, and $33{\pm}1.0^{\circ}C$). The developmental time of eggs ranged from 4.2 days at $15^{\circ}C$ to 0.9 days at $33^{\circ}C$. The developmental period of larvae was 4.2 days at $15^{\circ}C$, and slowed in temperatures above $27^{\circ}C$. The developmental period of pupa was 21.5 days at $15^{\circ}C$ and 7.6 days at $33^{\circ}C$. The mortality of eggs was 17.1% at $15^{\circ}C$ and 22.9% at $33^{\circ}C$, Larval mortalities (1st, 2nd, 3rd) were 24.1, 27.3 and 18.2%, respectively, at $15^{\circ}C$, Pupal mortalities were 18.2% at $15^{\circ}C$ and 23.1% at $33^{\circ}C$. The relationship between developmental rate and temperature fit both a linear model and a nonlinear model. The lower threshold temperatures of eggs, larvae, and pupae were 12.5, 10.7, and $6.3^{\circ}C$, respectively, and threshold temperature of the total immature period was $8.5^{\circ}C$. The thermal constants required to complete the egg, larval, and pupal stages were 33.2, 118.3, and 181.2 DD, respectively. The distribution of each development stages was described by a 3-parameter Weibull function.

• Korean Journal of Plant Resources
• /
• v.18 no.1
• /
• pp.1-7
• /
• 2005

This study was conducted to investigate the possibility of cultivating tea plants planted in the mountain area of west Gyeongnam province, Korea for 2 years from March 27th, 2001 to July 30th 2003. Ninety each plants collected from 5 different sife were cultivated in nursery cup pot$(\phi\;16cm)$. in the greenhouse condition and transplanted in 5 different location and monitored their survival growing state etc. The results obtained are as follow : 1. Survival rate tea plants after transfer to soil was relatively high Gaya-myeon Hanyang-gun with $90.0\%$ and the lowest in Buksang-meyon Geochang-gun with $80.0\%$. The tea plant collected from Gaya-myeon showed the best growing activity at early stage. 2. For the second year of harvesting time, survival rate was the highest in Machun-myeon Hamyang-gun with $92.2\%$ and the lowest was Buksang-myeon Geochang-gun with $76.7\%$. 3. For the 3rd year of harvesting time, it was impossible to data collection because of the most upper parts of plants were killed by severe freezing weather condition. In the Baekjeon-myeon, Hamyang-gun Buksang-myeon, Ungyang-myeon Geochang-gun, which are severly cold$(below\;-10^{\circ}C)$ in winter season, seems not a suitable places for tea plant cultivation since it is very different to harvest the young loaves in growing season. In conclnsion we could select two sites Gaya-myeon, Hapcheon-gun, Machun-myeon, Hamyang-gun, as tea plant cultivation in the mountain area of west-Gyeongnam province, korea.

• Korean Journal of Weed Science
• /
• v.7 no.1
• /
• pp.35-44
• /
• 1987

Differing in water conditions, the dry matter weight per plant was highest at 0 cm flooding depth, and was decreased at above 2 cm flooding depths. The shoot and spikes per pot developed best at flooding depths of 0 and 2 cm, but worst at -5cm or above 4cm flooding depths. The dry matter weight of shoots was linearly increased, but the weight of roots was sharply decreased according to high temperature after flower initation. The shoots and spikes per pot developed more effectively at 25$^{\circ}C$ than at 35 or 15$^{\circ}C$. The number of shoot and spike per pot were decreased according to higher shading. The effects of shading of 25-45% were not significantly small. The natural white and yellow spectra were the most effective to increase dry matter weight, shoots and spikes per pot. The dry matter weights of shoot and root per plant were not significantly different among at: 50 and 75% clay. The number of shoots were best and continuously increased at 75% clay, and the increments at 0 and 100% clays showed the lag period at early stage. The pattern of spikes was similar to shoots with less difference in various clay composition. The dry matter weight per plant in paddy field and upland field was basically similar. The numbers of shoot and spike were increased in response to increased fertilizer levels up to 20Kg per 10a of each component.

• Journal of Food Hygiene and Safety
• /
• v.35 no.6
• /
• pp.630-636
• /
• 2020

Listeria monocytogenes (L. monocytogenes) was responsible for several recall cases owing to its incidence in mushrooms exported from the Republic of Korea. In this study, we investigated the survival of L. monocytogenes in enoki mushroom (Flammulina velutipes) at different temperatures and the antilisterial effect of its organic acids. Enoki mushrooms were innoculated with L. monocytogenes (initial concentration 4.5 log CFU/g) and stored at 1-35℃, No growth of L. monocytogenes in enoki mushrooms was observed at 1℃ for 30 days. 3.0 log CFU/g growth of L. monocytogenes was also achieved after 36 h and 24 h at 30℃ and 35℃, respectively. To evaluate the antilisterial effect of the organic acids (acetic acid, lactic acid, malic acid), enoki mushrooms were treated with 1-3% of each acid for 10-30 min. The efficacy of malic acid and lactic acid was significantly higher than that of acetic acid. Over 3.0 log reductions were observed when L. monocytogenes in enoki mushrooms was immersed in 3% lactic acid and malic acid over 10 minutes or more. Therefore, it is necessary to keep enoki mushrooms at 1℃ during the export process and treat them with 3% lactic acid and malic acid for 10 min prior to consumption.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.4
• /
• pp.289-302
• /
• 2023

The study area was Gangnim-myeon, Hoengseong-gun, Gangwon-do, composed of the Chiaksan gneiss complex, and it was revealed that the concentrations of uranium (U) and thorium (Th) within the groundwater of the study area exceeded their water quality standards. Hence, artificial weathering experiments were conducted to elucidate mineralogically the mechanisms of their leaching using drilling cores obtained from the corresponding groundwater aquifers. First of all, the mineralogical compositions of core samples were observed, and the results indicated that the content of clinochlore, a member of the chlorite group of minerals that can form through low- and intermediate-temperature metamorphisms, was relatively higher. In addition, the Th concentration was measured ten times higher than that of U. The results of artificial weathering experiments suggested that the Th concentrations gradually increased through the dissolution of radioactive-element-bearing minerals up to the first day, and then they tended to decrease. It could be attributed to the fact that Th was leached with the dissolution of thorite, which might be a secondary mineral, and then dissolved Th was re-precipitated as the various forms of salt, such as sulfate. Even though the U content was lower than that of Th in the core samples, the U concentration was one hundred times higher than that of Th after the weathering experiments. It is likely caused by the gradual dissolution and desorption of U included in intensively weathered thorite or adsorbed as a form of UO₂²⁺ on the mineral surface. In addition, the leaching tendency of U and Th was positively correlated with the bicarbonate concentration. However, the concentrations between U and Th in groundwater exhibited a relatively lower correlation, which might result from the fact that they occurred from different sources, as aforementioned. Among various kinetic models, the parabolic diffusion and pseudo-second-order kinetic models were confirmed to best fit the dissolution kinetics of both elements. The period that would be taken for the U concentration to exceed its drinking-water standard was inferred using the regressed parameters of the best-fitted models, and the duration of 29.4 years was predicted in the neutral-pH aquifers with relatively higher concentrations of HCO₃, indicating that U could be relatively quickly leached out into groundwater.

• Journal of Korean Society of Forest Science
• /
• v.47 no.1
• /
• pp.37-43
• /
• 1980

This study have done to get the basical information that would be useful to make the ecological planting, selection of suitable species and weeding plan by the relation between the leading shoot elongation of several species and the climatic factors in the plantation. Sampling measurement have been done in the trial forest of Korean German Forest Management Project located in Joil-ri, Samnam-myeon and Ichcon-ri, Sangbug-myeon, Ulju-gun. The former is in lowland at 100m latidude and the latter is in highland of 600 m latitude. The elongation of leading shoot has been measured in the plantation with 10 days interval from the beginning of March in 1979 and the climatic datas has gotten in the weather station closed to the plantation. 1. The change of air temperature and rainfall in each measuring site is like Fig 1. and 2. The similar temperature in 600 m high latitude is coming about 10 days latter than 100 m latitude. 2. Genus pine as Pinus thunbergii, P. rigida, P. rigitaeda. P. koraiensis and P. taeda begin their leading shoot growth during March and air temperature in that time is around $6^{\circ}C$. In highland their beginning of leading shoot elongation has been found out 10 days latter than lowland. However Abies, Larix and Picea has shown to open their leading shoot during May, 40 days late in comparing with genus pine, and then temperature is making around $15^{\circ}C$. But Cryptomeria, Chamaecyparis and Cedrus deodora has shown their leading shoot opening in March in lowland and May in high land. The reason of late opening, specially in highland, seems to be the influence of winter frost. 3. Most of leading shoot elongation of genus pine has finished during the end 10 days of April and May under range of air temperate $10^{\circ}C$ and $20^{\circ}C$ and other species has finished most of their elongation during the end 10 days of May and June with air temperature range of $18^{\circ}C$ to $20^{\circ}C$. So the suitable season of weeding works show to genus pine in May and other species in June. 4. The leading shoot growth of genus pine has started earlier and closed earlier too than other species and, when over than $20^{\circ}C$ air temperature, their growth is decreasing quickly. Pices abies as well show to be decreased suddenly in over than $20^{\circ}C$ temperature. Other species show the similar trend when over than $22^{\circ}C$. This reason is considered as high temperature of summer season. 5. Annual elongated days of leading shoot of Picea abies is 50 days, Abies hollophylla 70 days, and more than 85 percentage of shoot growth of Pinus koraiensis and Larix leptolepsis are growing during 70 dys as well. The shoot growing days of Chamaecyparis, P. rigida, P. rigitaeda, P. taeda and P. shunbergii show longer period as over than 120 days. 6. The shoot elongation times per year of Abies and Picea has closed as one times and Genus pine is continuring their elongation more than two times. But Cryptomeria, Chamaecyparis, Cedrus deodora and Larix show one or two times elongation depending on the measuring site. The reason of continuring elongation more than than two times seems to be influenced by the temperature in summer season except the genetical reason. 7. Depending on the above results, as the high temperature in summer season could give the influence to grow the leading shoot in the plantation, this would be the considering point on the ecological planting and selection of the suitable species to the slope aspect. The elongation pattern by the season show to be the considering point too to decide the the weeding and fertilizer dressing time by the species.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.6
• /
• pp.909-919
• /
• 2010

The purpose of this study was to investigate the demand and use of fresh-cut produce in school foodservice and restaurant industries. The subjects of this survey study were 200 school nutritionists and 70 cooks or managers in the restaurant industry nationwide. The data were collected by means of self-administered or e-mail questionnaires. Data analysis was completed using the SPSS window (ver. 12.0) program including frequency, $\chi^2$-test and t-test. Survey questions assessed the general characteristic of respondents, and the supply, use, and demand of fresh-cut produce in school foodservice and restaurant industries. Over 74% of the subjects have used fresh-cut produce. Most of the school foodservice (84.0%) kept fresh-cut produce for one day, while restaurant industry (28.3%) kept them up to three days. The nutritionists of school foodservice and managers of restaurant industry considered origin and date of production as the most important factor, respectively, when fresh-cut produce were being used. Fresh-cut root vegetable, such as potato and carrot was used mostly. The main reason not to use the fresh cut produce was due to the distrust of the fresh-cut produce safety in school foodservice and cost in restaurant industry. The main problem in fresh-cut produce use was the need of rewashing (29.9%) in school foodservice and irregular size (39.0%) in restaurant industry. These results indicate that the quality standard and size specification must be prepared with production guideline of safe fresh-cut produce.