• 한국식품위생안전성학회지
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• 제12권4호
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• pp.304-309
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• 1997

A study was undertaken to determine the thermal inactivation of Escherichia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than pfosphate buffer (pH 7.1), with D values of 1.52~1.68 min at 6$0^{\circ}C$ and 1.51~1.63 min at 7$0^{\circ}C$ compared with 1.52~1.65 min at 6$0^{\circ}C$ and 1.26~1.61 min at 7$0^{\circ}C$ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (106 CFU/$m\ell$) was heated at 7$0^{\circ}C$. When E. coli O157:H7 was preheated at 48$^{\circ}C$ for 60 min in phosphate buffer before heating, D values were 1.28~1.60 min at 6$0^{\circ}C$, and 1.13~1.56 min at 7$0^{\circ}C$, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (109 CFU/$m\ell$), while ascorbic acid was no effect at low cell concentrations (109 CFU/$m\ell$).

• Applied Biological Chemistry
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• 제30권3호
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• pp.285-290
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• 1987

사과의 건조, 가공 중의 갈변을 방지하기 위한 기초 조사로서 후지 사과로부터 추출한 crude peroxidase의 열불활성화와 갈변 저해제의 저해 효과 등을 조사하였다. Peroxidase의 최적 pH와 온도는 p-phenylenediamine과 $H_2O_2$를 기질로 하였을 때 각각 5.5와 $35^{\circ}C$이었고, 열불활성화 반응은 biphasic으로 heat labile fraction의 $E_a$와 Z값은 각각 48.2kcal/mol 과 $11.2^{\circ}C$, heat resistant fraction의 $E_a$와 Z값은 각각 36.3kcal/mol과 $14.9^{\circ}C$이었다. Peroxidase에 의한 갈변은 sodium diethyldithiocarbamate와 potassium metabisulfite는 10mM에서, L-cysteine과 ascorbic acid는 1mM에서 현저하게 저해되었다.

• Applied Biological Chemistry
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• 제33권2호
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• pp.109-115
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• 1990

대두 STI의 열처리에 의한 불활성화에 L-cysteine 및 sodium sulfite의 첨가 효과를 조사하고, 대두 품종별 STI활성을 측정하였으며 활성도와 단백질 및 cysteine함량 그러고 소화율과의 관계를 비교하였다. 열처리에 의한 STI의 불활성화에 L-cysteine과 sodium sulfite의 첨가는 불활성화 효과를 크게 증가시켰으며 대두 품종간 불활성화 정도는 차이를 보이지 않았으며 L-cysteine과 sodium sulfite의 첨가는 불활성화된 STI의 재활생화를 크게 억제하였다. 품종별 STI의 활성도는 대두분말 g당 $64.7{\sim}86.47\;TIU$의 범위에 있었으며, 장백>힐>장엽, 광교>단엽>백운>단경>팔달, 새알, 덕유>황금 이었으며, 단백질 함량과 STI의 활성도와는 상관관계(r=-0.192)가 없는 것으로 나타났다. 품종별 cysteine 함량은 힐, 장백, 단경, 단엽, 황금, 백운, 장엽, 새알, 덕유, 광교, 활달의 순서이었으며, cysteine의 함량은 $73.5{\sim}40.0\;{\mu}mole/g$ 대두분 이었다. 또한 cysteine함량과 STI 활성도 사이에 정의 상관(r=0.6568)을 나타냈다. 품종별 소화율은 광교, 백운, 팔달, 단경, 새알, 힐, 장엽, 덕유, 황금, 장백, 단엽의 순서이었으며 $81.9{\sim}76.7%$ 정도이었다. 또한 소화율과 STI활성도 사이에는 부의 상관(r=-0.7695)을 나타내었다.

• BMB Reports
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• 제36권2호
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• pp.167-172
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• 2003

The kinetics of thermal inactivation of copper-containing amine oxidase from lentil seedlings were studied in a 100 mM potassium phosphate buffer, pH 7, using putrescine as the substrate. The temperature range was between $47-60^{\circ}C$. The thermal inactivation curves were not linear at 52 and $57^{\circ}C$; three linear phases were shown. The first phase gave some information about the number of dimeric forms of the enzyme that were induced by the higher temperatures using the "conformational lock" pertaining theory to oligomeric enzyme. The "conformational lock" caused two additional dimeric forms of the enzyme when the temperature increased to $57^{\circ}C$. The second and third phases were interpreted according to a dissociative thermal inactivation model. These phases showed that lentil amine oxidase was reversibly-dissociated before the irreversible thermal inactivation. Although lentil amine oxidase is not a thermostable enzyme, its dimeric structure can form "conformational lock," conferring a structural tolerance to the enzyme against heat stress.

• Food Science and Biotechnology
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• 제18권3호
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• pp.661-666
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• 2009

The heat tolerance and the inactivation kinetics of peroxidase (POD) and polyphenol oxidase (PPO) in pineapples (Ananas comosus) were studied in the temperature range $45-95^{\circ}C$. The kinetic parameters, such as deactivation rate constant (k), activation energy ($E_a$), and decimal reduction rate (D) of the thermal inactivation process, were determined. POD in pineapples showed biphasic inactivation behavior at temperatures range $45-75^{\circ}C$ but was monophasic at $85-95^{\circ}C$. This indicate that POD has 2 isozymes, namely heat labile and heat resistant, with $E_a$ of 68.79 and 93.23 kJ/mol, respectively. On the other hand, the heat denaturation of pineapple PPO could be described as simple monophasic first-order behavior with $E_a$ of 80.15 kJ/mol. Thus, the results of this study is useful in blanching technology where it shows a shortened time with higher temperature can be applied. The determination of the heat tolerance and inactivation POD and PPO, at different temperature range as done in the present work, was very important to improve the blanching process. This also will help to optimize the pineapple canning process which is one of the most important food industries in many tropical regions.

• 한국식품조리과학회지
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• 제12권1호
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• pp.54-59
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• 1996

Immunoglobulins (IgY) were isolated from egg yolk of hens immunized with bovine serum albumin(BSA). The stability of anti-BSA IgY against heat and pH was investigated. Antibody activity was measured by enzyme linked immunosorbent assay. IgY was relatively heat-stable and most of the antibody activity remained after heating up 65$^{\circ}C$ for 30 minutes. IgY was stable at pH 5-11. However, inactivation of IgY was observed below pH 4, or above pH 12. Inactivation of IgY proceeded rapidly at low pHs(pH 2-3). Most of the antigen binding activity was lost at low pHs probably because of some conformational changes.

• 한국식품영양과학회지
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• 제25권5호
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• pp.804-809
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• 1996

식품위생 관련 미생물 8종에 대한 방사선 단독 및 가열처리와의 병용처리에 의한 살균효과를 조사한 결과, 방사선 단독처리시는 공시균주들의 D$_{10}$ 값은 0.14~0.48 kGy로 나타났으며 그 중 Escherichia coli가 0.14 kGy로 감수성이 가장 높았다. 불활성화 계수는 2~3 kGy 조사시 4.54~21.43으로 나타났다. 가열 단독 처리시에는 D(min) 값이 $50\pm1^{\circ}C에서$ 는 10~40분, $60\pm1^{\circ}C에서는$ 5~15분 정도로 나타났다. 가열과 방사선과의 병용처리시는 D$_{10}$ 값이 0.04~0.31 kGy의 범위로 나타났고 불활성화 계수도 2~3 kGy 조사시 에는 6.45~75로 나타났다. 이상의 결과, 가열과 방사선의 병용처리는 균주들의 방사선 감수성을 현저하게 상승시킴을 알 수 있었다.있었다.

• 대한가정학회지
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• 제6권1호
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• pp.900-909
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• 1968

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.65-68
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• 2004

The purpose of the present study was to examine the efficacy and mechanism of fraction IV cold ethanol fractionation and pasteurization (60$^{\circ}C$ heat treatment for 10 h), involved in the manufacture of albumin from human plasma, in the removal and/or inactivation of the hepatitis A virus (HAV). Samples from the relevant stages of the production process were spiked with HAV and the amount of virus in each fraction then quantified using a 50% tissue culture infectious dose (TCID$\_$50/). HAV was effectively partitioned from albumin during the fraction IV cold ethanol fractionation with a log reduction factor of 3.43. Pasteurization was also found to be a robust and effective step in inactivating HAV, where the titers were reduced from an initial titer of 7.60 log TCID$\_$50/ to undetectable levels within 5 h of treatment. The log reduction factor achieved during pasteurization was $\geq$4.76. Therefore, the current results indicate that the production process for albumin has sufficient HAV reducing capacity to achieve a high margin of virus safety.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.19-25
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• 2006

With particular regards to the hepatitis A virus (HAV), a terminal dry-heat treatment ($100^{\circ}C$ for 30 min) process, following lyophilization, was developed to improve the virus safety of a solvent/detergent-treated antihemophilic factor IX concentrate. The loss of factor IX activity during dry-heat treatment was of about 3%, as estimated by a clotting assay. No substantial changes were observed in the physical and biochemical characteristics of the dry-heat-treated factor IX compared with those of the factor IX before dry-heat treatment. The dry-heat-treated factor IX was stable for up to 24 months at $4^{\circ}C$, The dry-heat treatment after lyophilization was an effective process for inactivating viruses. The HAV and murine encephalomyocarditis virus (EMCV) were completely inactivated to below detectable levels within 10 min of the dry-heat treatment. Porcine parvovirus (PPV) and bovine herpes virus (BHV) were potentially sensitive to the treatment. The log reduction factors achieved during lyophilization and dry-heat treatment were ${\ge}5.60$ for HAV, ${\ge}6.08$ for EMCV, 2.64 for PPV, and 3.59 for BHV. These results indicate that dry-heat treatment improves the virus safety of factor IX concentrates, without destroying the activity. Moreover, the treatment represents an effective measure for the inactivation of non-lipid enveloped viruses, in particular HAV, which is resistant to solvent/detergent treatment.