• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.317-325
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• 1988

The effects of various heat treatments of soy milk prepared from soy protein concentrate on growth and acid production by five species of lactic acid bacteria were investigated. Sensory property and sedimentation characteristics of soy yogurt prepared from heat-treated soy milk were also evaluated. Heat treatment of soy milk stimulated acid production by all cultures. Acid production was generally proportional to degree of heat treatment and acid production by all cultures except Streptococcus lactis was maximum in soy milk heated at $121^{\circ}C-1min$. However, viable cell count was not changed markedly by heat treatment of soy milk. Sensory property of soy yogurt beverage (SYB) prepared from soy milk heated at $95^{\circ}C-30min$ was better than that of unheated sample while sensory property of SYB prepared from soy milk heated at $121^{\circ}C-15min$ was inferior to that of unheated sample. Heat treatment of soy milk generally retarded sedimentation of curd in SYB.

• Journal of Nutrition and Health
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• v.28 no.2
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• pp.144-151
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• 1995

This study investigates the supplementing effects of milks by various heat treatment on growth performance and protein and calcium metabolism of rats. For 4 weeks, raw, LTLT-HTST-and UHT-processed milks were given to rats which fed on a calcium free, semi-synthetic diet containing 5%casein. There were no significant differences among the experimental groups in weight gain, feed efficiency ratio and the serum level of total protein and calcium. Also, no significant differences were showed in protein efficiency, nitrogen balance, apparent protein digestibiltiy and the contents of weight and calcium of the left femur as well as 2 incisors. However, the biological value of protein in the UHT-milk group was significantly higher than that of the raw-milk group. The apparent calcium digestibility and calcium balance in the UHT-milk group were higher than those in the raw-, LTLT- and HTST-milk groups. The weight of left femur in all the groups supplemented with various heat-treated milks was significantly impair the nutritive value of protein and calcium in milk. Futhermore, UHT-processing may improve the bioavailability of protein and calcium in milk.

• The Korean Journal of Food And Nutrition
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• v.8 no.2
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• pp.79-87
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• 1995

It is generally known that the protein of talk has allergenicity and the allerenicity Induces allergic diseases. Finding methods to reduce the allergenicity of the food and develop methods to make low allergic food is the purpose of this study. For this study, 1 tried various experimental methods : heat treatment, irradation with ultraviolet and microwaves treatment with polyphosphate, enzyme hydrolysis and PCA inhibition test using guinea pigs and degrees of hydrolysis. The results obtained are as follows. Heat treatment reduced allergenicity of milk protein. The higher the heat, the better the effect. Irradiating with ultraviolet and microwave increased both the degree of protein hydrolysis and PCA inhibition reduced the allergenicity. Ultraviolet was more effective than microwaves on milk protein. Enzyme treatment increased the degree of hydrolysis and PCA inhibition, and reduced allergenicity considerably. Neutrase was more effective than alcalase on milk protein. Adding Polyphosphate did not induced protein hydrolysis, but increased PCA inhibition and reduced allergenicity.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.895-899
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• 2002

Lysozyme activity in buffalo milk in relation to the period of lactation, parity of animal, weather conditions and udder infections was studied. Effect of storage and heat processing of milk on lysozyme activity was determined. Lysozyme activity was higher in buffalo milk than in cow milk. Buffalo colostrum showed lysozyme activity 5 times of that in mature milk. Lysozyme activity in buffalo milk was not influenced by the parity of animal and the stage of lactation, however, it increased during extreme whether conditions (winter and summer). Lysozyme in both cow and buffalo milk exhibited maximum activity at pH 7.4. Buffalo milk lysozyme was fully stable while the cow milk lysozyme was partly inactivated by pasteurization (low temperature-long time as well as high temperature-short time treatments). Lysozyme in buffalo milk was more stable than in cow milk during storage and heat treatment. A 10 to 50-fold increase in milk lysozyme activity was observed in mastitic cows. An assay of lysozyme activity in milk can be used to diagnose mastitis in cattle but not in buffaloes. Some buffaloes exhibited 1000 fold greater lysozyme activity and moderately raised somatic cell count in milk, but there was no sign of mastitis in these animals. A possible role of milk lysozyme in prevention of mastitis in buffaloes is discussed.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.540-544
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• 2012

During heat treatment and storage of milk, deteriorative reaction takes place, which consequently influence on the milk quality. In this study, formation of lactulose and furosine under different thermal conditions and storage conditions, and the ratio of lactulose and furosine (LU/FU) in presence of reconstituted milk powder were determined to establish chemical indicators for heat damages of milk and the adulteration of fresh milk in dairy field. The lactulose and furosine contents linearly increased with increased heating temperature and heating time. It showed high correlation between the formation of lactulose and furosine, and the treatment temperature and time (p<0.05). The lactulose and furosine concentration of HTST milk and UHT milk noticeably increased during storage at $30^{\circ}C$, but there was no noticeable increase of lactulose and furosine concentration at lower storage temperature. In the raw milk, the lactulose and furosine contents greatly increased with the addition of reconstituted milk. The increase level of furosine was much higher than that of lactulose, which consequently resulted in the lower LU/FU ratio in milk as increase of added reconstituted milk amounts. As comparing with raw milk, there was more than twice reduction in LU/FU ratios after the addition of reconstituted milk (p<0.05). It can be concluded that lactulose and furosine are suitable milk quality indicators of heat damage and for demonstrating improper addition of reconstituted milk powder.

• Food Science of Animal Resources
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• v.22 no.1
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• pp.50-54
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• 2002

The aim of this work to determine the formation of lactulose during heat treatment process as a contribution to the estabilishment of limits of chemical indicators for different types of heat processed milk and analyze of lactulose for the reconstituted milk added samples. The HTST(75$\^{C}$/15s) and UHT(130$\^{C}$/2∼3s) treatment realized with a pilot plant and heat-treated samples were stroed at 4, 10, 30$\^{C}$ for 4 weeks. Changes in lactulose was evaluated at 7 days intervals. The other heat treatment was sealed in glass tube and heated at 75$\^{C}$ for 10 to 120s and heated at 130$\^{C}$ for 2 to 60s in a thermostatically controlled constant temperature bath of glycerol. The reconstituted milk was made with full fat dry milk that reconstituted with deionized water to 10% total solid, and was added to milk at 10, 20, 30% respectively. The samples processed with a HTST pilot plant showed that lactulose was contained at 1.47∼1.52mg/10()ml and 8.19 ∼8.32mg/100ml for UHT-treated samples. Changes in the lactulose content of heat-treated samples during storage at 4 and 10$\^{C}$ for 4 weeks caused a slight increase, however a noticeable increase was observed at 30$\^{C}$ for 4 week. The glass tube samples showed that high correlations between relative increase in content of lactulose and increasing processing times(75$\^{C}$ : r = 0.986, 130$\^{C}$ : r = 0.987, respectively). Added with reconstituted milk would cause a increase of the lactulose content linear with increasing addition amount(r = 0.982). This results observed for lactulose in commercial milk samples would applied to the detection of chemical changes during heat treatment and illegal use of reconstituted milk.

• Journal of Dairy Science and Biotechnology
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• v.35 no.2
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• pp.121-133
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• 2017

A small amount of milk is sold as 'untreated' or raw in the US; the two most commonly used heat-treatments for milk sold in retail markets are pasteurization (LTLT, low-temperature long time; HTST, high-temperature short time) and sterilization (UHT, ultra-high temperature). These treatments extend the shelf life of milk. The main purpose of heat treatment is to reduce pathogenic and perishable microbial populations, inactivate enzymes, and minimize chemical reactions and physical changes. Milk UHT processing combined with aseptic packaging has been introduced to produce shelf-stable products with less chemical damage than sterile milk in containers. Two basic principles of UHT treatment distinguish this method from in-container sterilization. First, for the same germicidal effect, HTST treatments (as in UHT) use less chemicals than cold-long treatment (as in in-container sterilization). This is because Q10, the relative change in the reaction rate with a temperature change of $10^{\circ}C$, is lower than the chemical change during bacterial killing. Based on Q10 values of 3 and 10, the chemical change at $145^{\circ}C$ for the same germicidal effect is only 2.7% at $115^{\circ}C$. The second principle is that the need to inactivate thermophilic bacterial spores (Bacillus cereus and Clostridium perfringens, etc.) determines the minimum time and temperature, while determining the maximum time and temperature at which undesirable chemical changes such as undesirable flavors, color changes, and vitamin breakdown should be minimized.

• Food Science and Preservation
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• v.10 no.2
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• pp.236-240
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• 2003

This study was carried out to obtain fundamental data when developing new colostrum component fortified milk products. Residual immunoglobulin G (IgG) activities of both IgG fortified milk products under different pasteurization conditions and colostrum fortified milk powder products under different dissolving temperatures were measured. In the study, residual IgG activities of raw milk and IgG (50 mg and 250 mg) fortified milk products were sharply reduced upon increasing the temperature of heat treatment. After the low temperature long time (LTLT) treatment residual IgG activities of raw milk, IgG 50 mg and 250 mg fortified milk products decreased to 79%, 30％ and 21.6%, as compared to those before heat treatment respectively. However, almost no residual IgG activities were detected when IgG fortified milk was heated at 95$^{\circ}C$ for 15 sec. There was no significant change in the residual IgG activities of IgG fortified milk powder products upon different dissolving temperatures (30$^{\circ}C$, 40$^{\circ}C$, 50$^{\circ}C$ and 60$^{\circ}C$).

• Korean Journal of Food Science and Technology
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• v.8 no.1
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• pp.6-11
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• 1976

1. Three hundred and thirty three strains of thermoduric bacteria from raw milk, H.T.S.T. sterilized milk and U.H.T. sterilized milk in the market were isolated after heat treatment at $65^{\circ}C$ for 30 minutes. 2. By microscopical and physiological examination, including the tests for proteolysis and lipolysis, the isolates were identified as 125 strains of Bacillus stearothermophilus, 69 strains as Bacillus coagulans, 57 strains as Bacillus subtilis, 76 strains as Bacillus cereus and 3 strains as Lactobacillus thermophilus. 3. The susceptibility of the selected thermoduric strains to heat, the vegetative cells of some strains in skim milk survived the heat treatment at $65^{\circ}C$ for 30 minutes or $85^{\circ}C$ for 20 minutes but not survived at $100^{\circ}C$ for 10 minutes.

• Food Science and Preservation
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• v.13 no.2
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• pp.223-227
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• 2006

Optimal heat treatment conditions for maintaining the immune-activity of immunized milk with Helicobacter pylori antigen were studied Total bacterial count of immunized milk with H. pylori antigen decreased according to the increasing heating temperature and time. The viable tell number of immunized milk was $10^3\;CFU/mL$ after heat treatment for 30 min at $60^{\circ}C$, and coliform bacteria did not appear in immunized milk after heat treatment Immune-activity measured in terms of IgG concentration was maintained up to 99.99% after heat treatment for 30min at $60^{\circ}C$, but decreased rapidly below 50% after heat treatment above $70^{\circ}C$. The quality characteristics of immunized milk were examined during storage at $2^{\circ}C,\;4^{\circ}C\;and\;10^{\circ}C$. The pH, titratable acidity and total bacterial count were not changed significantly during 21 day storage at $2^{\circ}C\;and\;4^{\circ}C$, but rapidly changed after 7 day storage at $10^{\circ}C$. The immune-activity was kept well for 14 day storage at $2^{\circ}C,\;4^{\circ}C\;and\;10^{\circ}C$ but decreased rapidly after 14 days at every temperatures tested.