• Korean Journal of Food Science and Technology
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• v.11 no.3
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• pp.171-175
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• 1979

Thermal properties of crude papain and crude peroxidase from domestic papaya were investigated. The crude extract of papaya was inactivated at the temperature range of $60^{\circ}{\sim}90^{\circ}C$ at pH 7.0 and the rest of the activities of papain and peroxidase were determined, respectively. The heat inactivation of papain and papaya peroxidase was biphasic at low temperature. For the thermal inactivation of papain extract, the enthalpy of activation was 91.4 kJ/mol, the entropy of activation, -49.6 J/mol K, and the free energy of activation, 108.5 kJ/mol. The activation energy for the inactivation of papaya peroxidase was 168.5 kJ/mol, the entropy of activation, $200.4\;J/mol{\cdot}K$ and the free energy of activation, 99.7 kJ/mol. The thermal stability of papain showed that it has a possibility for use as a meat tenderizer. It was also discussed that papaya peroxidase could be more suitable as a biochemical criteria for heat treatment than papaya catalase.

• BMB Reports
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• v.29 no.1
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• pp.58-62
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• 1996

The structural changes in the electron donor side of the PSII reaction center have been monitored since heat treatment ($45^{\circ}C$ for 5 min) of thylakoids is known to decrease the oxygen evolving activity. In heat-treated spinach chloroplast thylakoids, the inhibitory effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) on the electron transport activity of the PSII reaction center from diphenyl carbazide to dichlorophenolindophenol became reduced approximately 3.8 times and [$^{14}C$]-labeled DCMU binding on the D1 polypeptide decreased to 25~30% that of intact thylakoid membranes, implying that the conformational changes of the DCMU binding pocket, residing on the D1 polypeptide, occur by heat treatment. The accessibility of trypsin to the $NH_2$-terminus of the cytochrome b-559 ${\alpha}$-subunit, assayed with Western blot using an antibody generated against the synthetic peptide (Arg-68 to Arg-80) of the COOH-terminal domain, was also increased, indicating that heat-treatment caused changes in the structural environments near the stromal side of the cytochrome b-559 ${\alpha}$-subunit, allowing trypsin more easily to cleave the $NH_2$-terminal domain. Therefore, the structural changes in the electron donor side of the PSII reaction center complexes could be one of the reasons why the oxygen evolving activity of the heat-treated thylakoid membranes decreased.

• Journal of Food Hygiene and Safety
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• v.11 no.3
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• pp.197-201
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• 1996

D10 values obtained for radiation alone in Bacillus subtilis and Clostridium perfrigenes were 0.35-0.48 kGy in vegetative cells, and 2~2.08 kGy in spores, respectively. Irradiation dose of 24 kGy completely inhibited spores. In the case of heat treatment, D50, 60 values ranged from 10 to 14 minutes in vegetative cells, and D70, 80, 90 values ranged from 10 to 140 minutes in spores. In the case of combined treatment with heat and radiation, D10 values ranged form 1 to 1.25 kGy in vegetative cells, and from 3.42 to 3.61 kGy in spores. Thus, resistance of cells to gamma radiation did not seem to be influences by pre-heating.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.441-446
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• 2006

The biological effects of heating and chemical treatment on castor meal were investigated in order to develop a procedure to inactivate its antigenic activity in a way that is suitable for industrial applications. A 1% solution of purified castor bean allergen (CB-1A) was heat-treated with or without exposure to NaOH and NaOCI (250 ppm each). CB-1A exhibited extreme stability when heat-treated alone. In the presence of NaOH and NaOCl, CB-1A showed a drastic decrease in antigenic activity as the temperature surpassed the critical level of $70^{\circ}C$. The gradual disappearance of disc gel electrophoresis bands presumably responsible for the allergenicity of CB-1A, along with the significant losses of the amino acids phenylalanine, methionine, arginine, histidine, and cysteine correlated with the loss of CB-1A activity. CB-1A showed a single symmetrical band in SDS acrylamide gel electrophoresis with an estimated molecular weight of 6,000 daltons. The chemical and heat treatments reduced the disulfide bond content of CB-1A by 9.1% with a coincident increase in sulfhydryl bonds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.591-595
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• 1990

A promoting effect of ginseng saponin on the growth recovery rate of Saccharomyces rouxii which was treated by heat was confirmed in previous report(22). In order to deduce the promoting effect on the growth recovery of the heat stressed yeast, the effect of ginseng saponin on the activity and the heat stability of the amylase produced by Sacchirromyces rouxii were observed. The amylase showed the highst activity at 0.01％ of saponin. At this concentration, the activity increased about 23％ compared to the control. Furthermore, the ginseng saponin showed a protective effect against thermal inactivation of the amylase produced by Saccharomyces rouxii.

• Preventive Nutrition and Food Science
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• v.20 no.1
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• pp.60-66
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• 2015

The aim of this study was to determine the heat-penetration characteristics using stationary and rotary retorts to manufacture Kimchi soup. Both heat-penetration tests and computer simulation based on mathematical modeling were performed. The sterility was measured at five different positions in the pouch. The results revealed only a small deviation of $F_0$ among the different positions, and the rate of heat transfer was increased by rotation of the retort. The thermal processing of retort-pouched Kimchi soup was analyzed mathematically using a finite-element model, and optimum models for predicting the time course of the temperature and $F_0$ were developed. The mathematical models could accurately predict the actual heat penetration of retort-pouched Kimchi soup. The average deviation of the temperature between the experimental and mathematical predicted model was 2.46% ($R^2=0.975$). The changes in nodal temperature and $F_0$ caused by microbial inactivation in the finite-element model predicted using the NISA program were very similar to that of the experimental data of for the retorted Kimchi soup during sterilization with rotary retorts. The correlation coefficient between the simulation using the NISA program and the experimental data was very high, at 99%.

• Journal of Dairy Science and Biotechnology
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• v.36 no.1
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• pp.49-71
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• 2018

Heat treatment is the most popular processing technique in the dairy industry. Its main purpose is to destroy the pathogenic and spoilage bacteria in order to ensure that the milk is safe throughout its shelf life. The protease and lipase that are present in raw milk might reduce the quality of milk. Plasmin and protease, which are produced by psychrotrophic bacteria, are recognized as the main causes of the deterioration in milk flavor and taste during storage. The enzymes in raw milk can be inactivated by heat treatment. However, the temperature of inactivation varies according to the type of enzyme. For example, some Pseudomonas spp. produce heat-resistant proteolytic and lipolytic enzymes that may not be fully inactivated by the low temperature and long time (LTLT) treatment. These types of enzymes are inhibited only by the high temperature and short time (HTST) or ultra-high temperature (UHT) treatment of milk.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.254-259
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• 1989

A radioprotective ginseng protein fraction was obtained from Korean white ginseng powder by the following isolation and purification procedures: Tris-HCI buffer extraction, 70% ammonium sulfate fractionation, CM-rellulosr column chromatography, heat inactivation and Sephadex G-75 column chromatography. This fraction was further purified by Sepharose 4B and Sephadex G-150 column chromatographies. Three fractions obtained were subjected to Native-PAGE and SDS-PAGE using gradient gels and the silver staining method. Molecular weights of the native proteins and their subunits were estimated.

• Korean Journal of Food Science and Technology
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• v.21 no.2
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• pp.185-191
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• 1989

The combined effects of heat treatment and ${\gamma}-irradiation$ on the inactivation of major lactic acid bacteria associated with Kimchi fermentation were investigated. The radiosensitivities $(D_{10}\;values)$ of lactic acid bacteria in case of a single treatment of irradiation were 0.61 kGy in Lactobacillus brevis, 0.60 kGy in Lactobacillus plantarum, 0.50 kGy in Leuconostoc mesenteroides, 0.4 kGy in Pediococcus cerevisiae, 0.39 kGy in Streptococcus faecalis. The heat sensitization $(D_{min}\;values)$ by a single treatment of heat ranged 9.2-15.6 at $50^{\circ}C$ and 3.7-5.5 at $60^{\circ}C$. Synegistic effects were shown in the radiosensitivities of Streptococcus faecalis, Pediococcus cerevisiae, Lactobacillus plantarum, and Lactobacillus brevis by the combined treatment(Dose multiplying factors ranged $1.20{\sim}1.56$). It seems, therefore, that the combined treatment can be applied to the radiation preservation of Kimchi, minimizing the side-effects like physical changes induced by the high dose irradiation or heat treatment.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.284-291
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• 1997

Microwave vacuum heating method (2450 MHz) was used for a low intensity of heat treatments. High vacuum under the microwave heating could bring low temperature condition. Inactivation of ${\alpha}-amylase,\;{\beta}-amylase$, glucoamylase and peroxidase by microwave vacuum heating were investigated at 60-$80^{\circ}C$. It was compared with conventional heating. The heating condition of microwave vacuum heating was confirmed by the destruction of ascorbic acid. When thermal inactivations of the enzymes by microwave vacuum heating were determined, it was less effective than that of conventional method at the initial stage of heating. It was due to a lag time of microwave heating. However, the heating time for complete inactivation of the enzymes by microwave vacuum heating could be reduced comparing with that of conventional heating. Optimum conditions for inactivation of the enzymes could be obtained by microwave vacuum heating.