• 한국식품위생안전성학회지
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• 제11권3호
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• pp.189-196
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• 1996

Based on microbiological-chemical test results under simulated time-temperature conditions, total plate count, coliform, and volatile basic nitrogen were selected as effective quality indicators for estimating probable shelf-life on Kim Pab dosirak marketed in convenience stores, and shelf-life at each storage temperature was calculated from regression equation between effective quality indicator standard limit and storage time. Estimated shelf lives of Kim Pab Dosirak were 17, 3 and 2 hours respectively under 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$. Because shelf-life was especially affected by intial values, regression analysis between initial effective quality indicator values and storage hours was performed for the estimation of probable shelf-life on Kim Pab during storage at 10, 20, or 3$0^{\circ}C$.

• 한국식품위생안전성학회지
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• 제16권2호
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• pp.103-110
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• 2001

예측식품미생물학(PFM)은 1980년대 후반 이후 식품미생물학 분야에서 새롭게 발생한 신학문 분야이다. PFM은 특별한 환경적 요인에 따른 미생물 특히, 병원성미생물의 반응(사멸과 생존)을 예측하기 위하여 수학적인 모델을 이용한 것이다. 현재까지 개발된 PFM모델중 완전한 것은 없지만, 어떤 특정 조건하에서는 신속하고 객관적으로 미생물의 반응을 예측하는데 이용될 수 있다는 장점 때문에, HACCP시스템, Risk Assessment 등에서 응용 가능성이 커지고 있다. 본 연구는 PFM 모델중 PMPwin5.1을 이용하여, 우유 저장에 대한 HACCP시스템 중 미생물학적 위해요소 분석, CCP 및 CL설정에 대한 방법론적 예를 제시하였다. 모델에 대한 초기조건으로 우유와 동일한 물리화학적 조건인 pH 6.7, Aw 0.993, NaCl 1.3%을 고정변수로 하고, 저장온도(4~15$^{\circ}C$)를 변이변수로 선정하여, 온도에 따른 주요 병원성미생물의 generation time, lag phase duration, infective dose에 도달하는데 걸리는 시간을 산출하였다. 이 결과를 바탕으로 온도의 변화에 따른 각 병원성미생물의 성장을 안전정도에 따라 “안전온도범위(Safe temperature zone)”, “주의온도범위(Caution temperature zone)”, “위험온도범위(Danger temperatue zone)”로 분류하였으며, 이들 분류는 우유의 유통기간인 5일을 기준으로 각 병원성미생물의 lag phase duration, infective dose에 도달하는 시간에 따라 결정하였다. 이러한 결과는 우유의 HACCP시스템에 있어, 위해요인 분석시 위해요인의 분류 및 위해요소간의 위해 정도의 우선순위 부여에 보조적인 수단으로 이용될 수 있다. 또한 유통.저장단계에서 병원성미생물의 상징에 대한 온도수준을 나타내므로, 이 단계를 CCP로 설정할 수 있고, CCP에 대한 CL은 주위온도범위내에서 설정할 수 있다. 그리고 허용수준에 대한 온도의 범위를 제시하므로 모니터링이나 검증에서도 이용할 수 있다.

• 한국식품저장유통학회지
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• 제4권1호
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• pp.11-15
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• 1997

This experiment carried out to find the storage life according to the kinds of packaging material. Sheridan(Grape) which was fumigated SO2 were wrapped with polyethylenes(Bio-PE and PE) and stored at $0^{\circ}C$ under 90% RH modified condition. The resorts were summarized as follow. Natural weight loss was increased according to the storage time during the 135days storage that was only 1.0-1.7% in sealing section while 10% in non-sealing section. Abonrmal fruits were increased as the storage time was increased and it was 6.6-6.7% in sealing section while 100% in non-sealing during the 135days storage. Quality of appearance and taste are better in sealing section than non-sealing section and it was good in Bio-PE sealing section between packaging materials. Moistrue content was de creased as the storage range was increased and the decreasing rate of that during the storage was 4.9-5.2% in sealing section between treatments. During the storage range increased, the soluble solid degree was increased in non-sealing section but decreased in sealing section.

• Clinical and Experimental Reproductive Medicine
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• 제51권1호
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• pp.42-47
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• 2024

Objective: This study evaluated the effects of temperature and storage time on the quality and DNA integrity of freeze-dried sperm from individuals with normozoospermia. Methods: Normal sperm samples from 15 men aged 24 to 40 years were studied. Each sample was divided into six groups: fresh, freezing (frozen in liquid nitrogen), freeze-dried then preserved at room temperature for 1 month (FD-1m-RT), freeze-dried then preserved at room temperature for 2 months (FD-2m-RT), freeze-dried then preserved at 4 ℃ for 1 month (FD-1m-4 ℃), and freeze-dried then preserved at 4 ℃ for 2 months (FD-2m-4 ℃). The morphology, progressive motility, vitality, and DNA integrity of the sperm were evaluated in all groups. Results: In all freeze-dried groups, sperm cells were immotile after rehydration. The freeze-dried groups also showed significantly less sperm vitality than the fresh and frozen groups. Significantly more morphological sperm abnormalities were found in the freeze-dried groups, but freeze-drying did not lead to a significantly higher DNA fragmentation index (DFI). The DFI was significantly higher in the FD-2m-RT group than in the other freeze-dried groups. Conclusion: The freeze-drying method preserved the integrity of sperm DNA. The temperature and duration of storage were also identified as factors that influenced the DFI. Accordingly, more research is needed on ways to improve sperm quality in the freeze-drying process.

• 설비공학논문집
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• 제12권6호
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• pp.609-615
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• 2000

The energy conservation is one of the most important issues in recent years. Especially, the energy conservation through improved control strategies is one of the most highly possible area to be implemented in the near future. The energy conservation of the ice storage system can be accomplished through the improved control strategies. A real time building load prediction algorithm was developed. The expected highest and the lowest outdoor temperature of the next day were used to estimate the next day outdoor temperature profile. The measured dry bulb temperature and the measured building load were used to estimate system parameters by using the on-line weighted recursive least square method. The estimated hourly outdoor temperatures and the estimated hourly system parameters were used to predict the next day hourly building loads. In order to see the effectiveness of the building load prediction algorithm, two different types of building models were selected and analysed. The simulation results show less than 1% in error for the prediction of the next day building loads. Therefore, this algorithm may successfully be used for the development of improved control algorithms of the ice storage system.

• Nuclear Engineering and Technology
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• 제4권4호
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• pp.322-326
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• 1972

상온에서 (NH$_4$)$_2$CrO$_4$를 원자로에 조사하고, 조사된 후 상온에서 보관된 시간과 $^{51}$ Cr의 잔류값을 반응속도론적으로 연구하였다. 또한 원자로 조사시간 변화에 따르는 $^{51}$ Cr의 잔류값을 반응속도론적으로 고찰하였으며 일차반응으로 표시 될 수 있었다.

• 한국축산식품학회지
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• 제32권4호
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• pp.448-457
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• 2012

The predictive ability for off-flavor development and quality change of ground beef was evaluated using a microbial time temperature indicator (TTI). Quality indices such as off-flavor detection (OFD) time, color, pH, volatile basic nitrogen (VBN), aerobic mesophilic bacteria (AMB) counts, and lactic acid bacteria (LAB) counts were measured during storage at 5, 10, 15, and $25^{\circ}C$, respectively. Arrhenius activation energies (Ea) were estimated for temperature dependence. The Ea values for TTI response (changes in titratable acidity (TA)), VBN, AMB counts, LAB counts, and freshness, which is defined based on OFD time for quality indices of ground beef, were 106.22 kJ/mol, 58.98 kJ/mol, 110.35 kJ/mol, 116.65 kJ/mol, and 92.73 kJ/mol, respectively. The Ea of microbial TTI was found to be closer to those of the AMB counts, LAB counts, and freshness. Therefore, AMB counts, LAB counts, and freshness could be predicted accurately by the microbial TTI response due to their Ea similarity. The microbial TTI exhibited consistent relationships between its TA change and corresponding quality indices, such as AMB counts, LAB counts, and freshness, regardless of storage temperature. Conclusively, the results established that the developed microbial TTI can be used in intelligent packaging technology for representing some selected quality indices of ground beef.

• 방사성폐기물학회지
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• 제20권3호
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• pp.297-306
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• 2022

The acoustic emission (AE) is proposed as a feasible method for the real-time monitoring of the structural damage evolution in concrete materials that are typically used in the storage of nuclear wastes. However, the characteristics of AE signals emitted from concrete structures subjected to various environmental conditions are poorly identified. Therefore, this study examines the AE characteristics of the concrete structures during uniaxial compression, where the storage temperature and immersion conditions of the concrete specimens varied from 15℃ to 75℃ and from completely dry to water-immersion, respectively. Compared with the dry specimens, the water-immersed specimens exhibited significantly reduced uniaxial compressive strengths by approximately 26%, total AE energy by approximately 90%, and max RA value by approximately 70%. As the treatment temperature increased, the strength and AE parameters, such as AE count, AE energy, and RA value, of the dry specimens increased; however, the temperature effect was only minimal for the immersed specimens. This study suggests that the AE technique can capture the mechanical damage evolution of concrete materials, but their AE characteristics can vary with respect to the storage conditions.

• 한국식품영양학회지
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• 제12권4호
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• pp.409-414
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• 1999

In order to investigate the changes of rice qualities during 4 years storage of paddy stored in ware-house of normal temperature condition. Temperature in warehouse was changed more than 3$0^{\circ}C$ under the influence of average temperature outside of a warehouse. Water content of paddy was not increased over 15% But as average temperature in warehouse was gone up 18$^{\circ}C$ from June to September every years it was supposed that these periods were to be deterioration of rice quality. On investigation of change in paddy it was supposed that these periods were to be deterioration of rice quality. On investigation of change in paddy components during the long term storage, reducing, sugar, amylose, crude protein were increased 0.24%, 19.23%, 7.02% at enterance time to 0.5%, 20.31% 7.46% 4 years later respectively. Max viscosity final visocity and set back value by amylograph were increased 449B,U 610B.U, 161B.U to 493B.U, 715B,U 222B.U but breakdown was decreased 125B.U to 76B.U with the increase of storage period. Gel consistency of rice stored was decreased 44.7mm at enterance time to 39,9mm 4years later. Fatty acid was increased remarkably 4.5KOHmg/100g to 24.4KOHmg/100g. Germination ratio and germ activity of paddy during long-term storage were decreased 97%, 100% to 0%, 0.4% respectively, With the increase of storage period contaminated paddy by molds increased and its by bacteria decreas-ed.

• 산업식품공학
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• 제15권4호
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• pp.311-317
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• 2011

활성글루텐이 첨가된 쌀 식빵 프리믹스를 5, 25, $35^{\circ}C$의 저장온도에서 4개월 동안 저장하면서 이화학적, 반죽특성, 호화특성 및 제빵특성에 미치는 영향에 대하여 조사하였다. 쌀 식빵 제조 시 활성글루텐의 적정 첨가량은 14-17%로 판단되었다. 쌀 식빵 프리믹스의 pH, 침전가 및 Pelshenke값은 저장기간이 증가함에 따라서 감소하는 경향을 보였으며, 특히 Pelshenke 값은 35$^{\circ}C$ 저장시에 그 수치가 현저히 감소하였다. 쌀 식빵 프리믹스의 수분 함량은 변화가 적었으나, 보수력과 알칼리수 흡수율은 저장온도가 상승함에 따라서 증가하는 경향을 보였다. Mixograph의 peak time과 width at 8.00 min은 저장온도가 상승함에 따라서 유의적으로 증가하는 현상을 보였다. Rapid Visco Analyser에 의한 호화 특성 중 peak viscosity와 setback은 저장 온도가 상승함에 따라서 다소 증가하는 현상을 보였으며, 저장기간이 길어짐으로써 유의적으로 증가하였다. 프리믹스로 제조한 쌀 식빵의 비용적은 저장전에 비해 저장 중 온도가 높아짐에 따라서 그 감소 폭이 컸으며, 쌀 식빵의 경도는 증가하여 쌀가루 전분의 노화가 밀가루에 비해 보다 빠른 속도로 진행되는 것으로 나타났다.