• 한국식품영양과학회지
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• 제35권10호
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• pp.1394-1398
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• 2006

pH 전이공정에 따라 어육 단백질을 회수하고 드럼건조하여 분말 단백질을 제조한 후, 이들 단백질의 몇 가지 식품학적 기능성을 측정하였다. 건조 어육 단백질 분말의 용해도는 pH 7.0으로 조절한 단백질이 PH 5.5에 비하여 높았다. 유화활성지표는 $0.035\sim0.043m^2/g-protein$(pH 5.5 단백질 분말)로 비교적 낮았다. 그리고 유화안정성, 거품능 및 거품안정성은 관측되지 않았다. 점도 값은 수리미 단백질의 1/10에 불과한 $50,200\sim39,000\;cP$의 범위였다. 수분과 지방흡착능력은 각각 $2.63\sim2.89g-water/g$과 $2.13\sim2.17g-oil/g$이었고, 입자의 크기와 pH에 따른 영향은 없었다. 이 같은 실험 결과는 지방흡착을 위한 육의 대체제로 patty 제품 등에 건조 어육 단백질을 적용할 수 있을 것으로 보인다.

• 한국토양비료학회지
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• 제36권4호
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• pp.210-217
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• 2003

산화물에 대한 카드뮴의 흡착특성을 모사하기 위하여 토양에 존재하는 대표적 산화광물인 침철광과 석영을 대상으로 회분형 카드뮴 흡착실험을 수행하였다. 토양 광물에 대한 카드뮴의 흡착을 예측하기 위해 기존의 경험적 흡착모델 대신 표면착물 모델을 적용하였다. 모델을 검증하기 위하여 카드뮴의 흡착에 영향을 미치는 pH, 중금속 농도, 산화물 농도 및 이온강도 등의 인자를 조절하며, 다양한 조건하에서 회분형 흡착실험을 수행하였다. 실험결과, 카드뮴의 농도가 증가함에 따라 pH에 따른 흡착 곡선은 알칼리 쪽으로 평행하게 이동하였다. 흡착 실험으로부터 계산한 50%의 카드뮴이 흡착되는 pH인 $pH_{50}$은 합성 침철광이 5.25로 석영의 7.83에 비해 매우 낮아 카드뮴에 대한 표면 결합력이 석영에 비해 합성 침철광이 우세함을 시사하였고 이는 모델의 모사 결과와도 잘 부합하였다. 또한 배경전해질로 사용한 $KNO_3$의 이온강도는 카드뮴의 흡착에 영향을 미치지 않았다. 따라서 카드뮴은 산화광물 표면에 내부이온흡착 메커니즘에 의하여 흡착되는 것으로 판단할 수 있었다.

• 한국환경농학회지
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• 제12권2호
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• pp.169-175
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• 1993

유기인계 화합물중 독성이 매우 강한 O-ethyl S-methyl ethylphosphonothioate (1)의 화학적, 대사적 산화생성물들에 대한 $^{31}P-NMR$ 분석에서 주된 산화 생성물인 O-ethyl ethylphosphonic acid (2)의 chemical shift가 MCPBA 반응에서 40.15ppm, MMPP 반응에서 30.98ppm, microsomal oxidation system에서 29.31ppm, 그리고 집파리 생체실험에서 29.10ppm으로 반응조건에 따라 서로 상당히 상이하게 관찰되었다. 이 산화 생성물의 $^{31}P-NMR$ spectrum 상에서의 chemical shift에 대한 용매효과는 deutero-chloroform을 사용했을때 30.70ppm, 극성 용매인 deuterium oxide를 사용했을때 40.15ppm으로 관찰되었으며, pH에 대한 효과는 pH 3, 5.6, 14에서는 30ppm을 전후하여, pH 1의 강산성 조건하에서는 47.91ppm에서 나타났다. 이는 유기산 형태의 생성물 (2)가 ionized form이 형성될수있는 조건하에서는 산소원자의 비공유전자쌍들에 의하여 인원자가 차폐되어 chemical shift가 upfield쪽으로 이동을하고, 반면 비극성과 강산성 조건하에서는 Protonated form으로 존재하여 인(燐)원자에 대한 차폐효과가 줄어들기 때문에 downfield쪽으로 이동하는 것으로 관찰되었다.

• 한국미생물·생명공학회지
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• 제19권5호
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• pp.433-438
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• 1991

Phenylalanine 고생산용 plasmid pSY130-14는 $\lambda$-phage 유래 온도감수성을 가지고 있으므로 $cI_{857}$ repressor와 PL과 PR을 온도를 올려 phenylalanine의 생산을 유도한다. pSY130-14를 갖는 E.coli AT2471은 kanamycin 무첨가, $38.5^{\circ}C$, 48시간에서 약 30%로 plasmid가 없어지며 첨가에서 안정성이 떨어졌다가 배양시간과 더불어 올라갔는데, 이것은 생육에 피요한 kanamycin gene과 ori만이 남는 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.62-69
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• 1999

In order to investigate the critical amino acid residues involved in the catalytic activities of $\beta$-cyclodextrin glucanotransferase ($\beta$-CGTase) excreted by Bacillus firmus var. alkalophilus, the amino acid residues in $\beta$-CGTase were modified by various site-specific amino acid modifying reagents. The cyclizing and amylolytic activities of $\beta$-CGTase were all seriously reduced after treatment with Woodward's reagent K (WRK) modifying aspartic/glutamic acid, N-bromosuccinimde (NBS) modifying tryptophan, and diethylpyrocarbonate (DEPC) modifying histidine residues. The roles of tryptophan and histidine residues in $\beta$-CGTase were further investigated by measuring the protection effect of various substrates during chemical modification, comparing protein mobility in native and affinity polyacrylamide gel electrophoresis containing soluble starch, and comparing the $K_m$ and $V_{max}$ values of native and modified enzymes. Tryptophan residues were identified as affecting substrate-binding ability rather than influencing catalytic activities. On the other hand, histidine residues influenced catalytic ability rather than substrate-binding ability, plus histidine modification had an effect on shifting the optimum pH and pH stability.

• 한국의류산업학회지
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• 제24권6호
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• pp.775-781
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• 2022

As part of research to develop a permanent wave-reducing agent for hair, in the current study, 0.1%-1.0% of Polyquaternium-10 was added to a permanent reagent containing Nicotinoyl Dipeptide-23 to prepare the agent, which was tested on damaged hair. The pH change was relatively stable even after a date, but due to the hair's natural composition, 0.1%-0.6% of the Polyquaternium-10 concentration according to pH was suitable. The temperature safety experiment demonstrated it to be stable at a high temperature and at room temperature, but when a Polyquaternium-10 concentration of 0.9% or higher was added at 0℃, coagulation occurred. In terms of the force efficiency of permanent wave formation, wave efficiency lowered as the concentration increased: the longer the wave lasts, the lower the Polyquaternium-10 concentration. The permanent moisture content was found to be higher as the concentration of Polyquaternium-10 increased. Therefore, when Polyquaternium-10 is applied to the permanent wave-reducing agent, considering stability, permanent formation, durability, and moisture rate, the most suitable concentration was found to be that of Polyquaternium-10 in the cysteine-reducing agent. A novel finding from this study is that as the concentration of Polyquaternium-10 increases, the consistency of the permanent wave-reducing agent changes, shifting from a liquid to a viscous liquid formulation.

• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.246-253
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• 2017

Objective: Present study explores the effect of hot summer period on the glycolytic rate of early post-mortem meat quality of Ghungroo and Large White Yorkshire (LWY) pig and comparative adaptability to high temperature between above breeds by shifting the expression of stress related genes like mono-carboxylate transporters (MCTs) and heat shock proteins (HSPs). Methods: Healthy pigs of two different breeds, viz., LYW and Ghungroo (20 from each) were maintained during hot summer period (May to June) with a mean temperature of about $38^{\circ}C$. The pigs were slaughtered and meat samples from the longissimus dorsi (LD) muscles were analyzed for pH, glycogen and lactate content and mRNA expression. Following 24 h of chilling, LD muscle was also taken from the carcasses to evaluate protein solubility and different meat quality measurements. Results: LWY exhibited significantly (p<0.01) higher plasma cortisol and lactate dehydrogenase concentration than Ghungroo indicating their higher sensitivity to high temperature. LD muscle from LWY pigs revealed lower initial and ultimate pH values and higher drip loss compared to Ghungroo, indicating a faster rate of pH fall. LD muscle of Ghungroo had significantly lower lactate content at 45 min postmortem indicating normal postmortem glycolysis and much slower glycolytic rate at early postmortem. LD muscle of LWY showed rapid postmortem glycolysis, higher drip loss and higher degrees of protein denaturation. Ghungroo exhibited slightly better water holding capacity, lower cooking loss and higher protein solubility. All HSPs (HSP27, HSP70, and HSP90) and MCTs (MCT1, MCT2, and MCT4) in the LD muscle of pigs inclined to increase more in Ghungroo than LWY when exposed to high temperature. Conclusion: Effect of high temperature on the variation of HSPs and MCTs may play a crucial role in thermal tolerance and adaptation to different climatic conditions, pH regulation, muscle acidification, drip loss, protein denaturation and also in postmortem meat quality development.

• 한국식품조리과학회지
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• 제13권3호
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• pp.364-368
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• 1997

김치의 비타민 C 함량은 초기값에 비해 증가되었다가 감소하는 것으로 알려져 있어 이에 물김치를 담가 발효, 숙성온도를 달리하여 그 국물에 대하여 pH, 산도, 비타민 C 함량, 총균수, 젖산균수의 변화를 살펴본 결과는 다음과 같다. 3$0^{\circ}C$에서 1일간 숙성시킨 후 비타민 C 함량은 최고에 달해 20 mg% 정도를 나타냈으며, 이때의 pH는 4.5 내외, 산도는 0.2 lactic acid %였고, 미생물균수는 최고 $10^{8}$ CFU/$m\ell$를 나타냈으며 대부분을 젖산균이 차지했다. 이 결과는 그후 온도를 낮춰 15$^{\circ}C$, 4$^{\circ}C$에서 9일간 숙성을 시켜도 차이가 나지않았다. 15$^{\circ}C$에서 발효, 숙성시킨 김치는 최고의 비타민 C 함량인 15 mg%의 비타민 C 함량을 나타낼 때까지 4~5일이 소요되었으며, 이때의 pH는 4.0, 산도는 0.15 lactic acid %였다. 한편 15$^{\circ}C$에서 1일간 발효 후 4$^{\circ}C$에서 숙성시킨 경우에도 이 수준까지 떨어지지 않았다. 4$^{\circ}C$ 발효, 숙성의 경우에는 pH와 산도가 저장 10일 동안 초기값과 크게 달라지지 않았으며, 비타민 C가 증가하지 않아 약 10 mg%에 머물렀다.

• 전자통신동향분석
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• 제35권1호
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• pp.1-11
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• 2020

The Korean domestic media environment is seeing a rapid and dynamic change. Consumer media behavior is shifting from TV to smartphones, and from traditional media, such as terrestrial TV and cable, to intelligent Internet-based media, such as OTT channels and social media. This affects the profit structure of each media company and the competition among them, furthermore, the competitiveness of media services. In this regard, we propose a domestic UHD activation plan after evaluating the competitiveness of each media based on the analysis of the changes in the domestic media environment and the status of UHD services.

• Asian-Australasian Journal of Animal Sciences
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• 제13권9호
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• pp.1219-1227
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• 2000

Rumination behavior, in vivo digestibility of cell wall constituents, particle size reduction in the rumen, and retention time in the digestive tract of sheep were examined using rice and oat straw as roughage sources. The in sacco digestibility, rumen fermentation, and microbial population and internal adenosine 5-triphosphate (ATP) content were also determined under feeding conditions of high-roughage and high-concentrate diets. Chewing number and time in rumination behavior were higher with rice straw than with oat straw, while the in sacco and in vivo DMD of rice straw were consistently lower than those of oat straw. Rice straw also showed higher frequency of thinner and longer particles in the rumen contents and lower retention time in the whole digestive tract as compared to those of oat straw. Rice straw was more effective to maintain the ruminal pH than oat straw, being reflected in higher internal ATP content of large-type protozoa on the high- concentrate diet. Changes in the ruminal microflora by shifting from the low- to the high- concentrate diet were also different between rice and oat straw.