• 한국유가공학회:학술대회논문집
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• 2005.10a
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• pp.11-19
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• 2005

Heat treatment is essential for hygienic safety and for extending shelf-life of milk. Heating of milk affects principally its physicochemical, nutritional and organoleptic properties. The most important changes are the decrease in whey protein solubility and the decrease in stability of casein micelles. Maillard reactions are also important and undesirable consequences.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.183-183
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• 2019

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.183-191
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• 1990

Soy milk prepared from soy protein concentrate was added with each of four types of milk products. Acid production and growth of five species of lactic acid bacteria(LAB) in soy milk and sensory property of soy yogurt were investigated. Acid production by LAB increased in proportion to concentration of milk products added to soy milk. Among the four milk products tested, whey powder or skim milk powder stimulated acid production by LAB more than whole milk powder or modified milk powder. Stimulating effect by whey powder on acid production by LAB was greater than other milk products at low concentration. Acid production by LAB in soy milk added with glucose or milk products significantly increased during fermentation. Sensory property of soy yogurt added with whole milk powder or skim milk powder was better than that of reference (soy yogurt added with glucose) while sensory property of soy yogurt added with whey powder or modified milk powder was Inferior to that of reference.

• Applied Biological Chemistry
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• v.31 no.4
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• pp.361-370
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• 1988

To investigate the interaction between whey and soybean protein, thermal changes of component proteins were analyzed by column chromatography and gel electrophoresis. In the Sephadex G-200 chromatography of the mixture treated at above $80^{\circ}C$, the amount of low molecular weight proteins and high molecular aggregates were increased. This implicated that dissociation of 1ls globulin into subunits and the formation of soluble aggregates between these subunits and whey proteins that contain thiol and disulfide groups. These interaction between soy proteins and ${\beta}-lactoglobulin$, ${\alpha}-lactalbumin$, and proteose-peptone 3 were confirmed by gel electrophoresis. Bovine serum albumin, Immunoglobulin-G(H), Lactoferrin, 1ls-subunits(basic and acidic), and subunit of 7s globulin were also considered to interact each other depending on the condition of the salt solutions.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.83-92
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• 2012

This study was performed for analyzing the general composition and the change in the quality of soymilk-derived yogurts manufactured by adding skim milk and whey powder to soymilk heat-treated at $95^{\circ}C$/5 min and $120^{\circ}C$/10 min, respectively. 1. During the storage of soymilk yogurt, the concentrations of total solids, protein, fat, and lactose slightly decreased, whereas viscosity, content of ash and NPN, and the number of lactic acid bacteria remained unchanged. 2. The pH and titratable acidity changed rapidly in all soymilk yogurts after 3 h of incubation. 3. We found $7.8{\times}10^8$ lactic acid bacteria in the control sample, $4.7{\times}10^8$ and $5.02{\times}10^8$ in soymilk yogurt with skim milk, respectively, and $5.9{\times}10^8$ and $5.5{\times}10^8$, respectively in soymilk yogurt with whey powder according to degree of heat treatment with $95^{\circ}C$/5 min and $120^{\circ}C$/10 min. 4. The viscosity of yogurt samples became lower as the heat treatment increased in temperature and in the length of time. 5. The value of sensory evaluation was relatively high in soymilk yogurt with the added skim milk, which was heat-treated $95^{\circ}C$/5 min; however, the value was significantly lower than that of the control sample. 6. Lactose, glucose, and galactose were detected in all samples because lactose is degraded into glucose and galactose within 3 h of inoculation.

• Journal of Microbiology and Biotechnology
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• v.20 no.5
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• pp.950-957
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• 2010

Serratiopeptidase (SRP), a 50 kDa metalloprotease produced from Serratia marcescens species, is a drug with potent anti-inflammatory property. In this study, a powerful statistical design, evolutionary operation (EVOP), was applied to optimize the media composition for SRP production in shake-flask culture of Serratia marcescens NRRL B-23112. Initially, factors such as inoculum size, initial pH, carbon source, and organic nitrogen source were optimized using one factor at a time. The most significant medium components affecting the production of SRP were identified as maltose, soybean meal, and $K_2HPO_4$. The SRP so produced was not found to be dependent on whey protein, but rather was notably induced by most of the organic nitrogen sources used in the study and free from other concomitant protease contaminant, as revealed by protease inhibition study. In addition, experiments were performed using different sets of EVOP design with each factor varied at three levels. The experimental data were analyzed with a standard set of statistical formula. The EVOP-optimized medium, with maltose 4.5%, soybean meal 6.5%, $K_2HPO_4$ 0.8%, and NaCl 0.5% (w/v), gave a SRP production of 7,333 EU/ml, which was 17-fold higher than the unoptimized media. The application of EVOP resulted in significant enhancement of SRP production.

• Journal of Dairy Science and Biotechnology
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• v.30 no.2
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• pp.93-109
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• 2012

This study was performed to investigate the effects of added whey protein concentrates (WPC) and whey powder (WP) on the quality and shelf life of Tofu, a traditional food in Korea. Combined whey powder and whey protein concentrates were obtained at drainage after the casein was separated by using rennet enzyme or acidification of milk. We manufactured whey Tofu and evaluated its nutritional quality by testing, the general composition for yield, moisture, pH, crude protein, crude fat, carbohydrate, rheology, sensory properties, and change during storage. 1. The general compositions of WPC and WP were as follows: (a) WPC: moisture, 5.9%; crude protein, 56.2%; crude fat, 0.1%; carbohydrate, 32.6%; ash, 5.2%; and pH 5.93 and (b) WP: moisture, 3.7%; crude protein, 13.2%; crude fat, 1.6%; carbohydrate, 74.4%; ash, 7.1%; and pH, 6.65. 2. The yield of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL=6:4 > $CaCl_2$:GDL=9:1 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=8:2 and (b) in WP, 2% addition was the highest (265%) at $13.3g/cm^2$, but with 4% addition WP was the lowest (184%) at $22.2g/cm^2$. 3. The moisture content of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL = 6:4 > $CaCl_2$:GDL=9:1 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=8:2 and (b) in WP, 2% addition was the highest at 79.82% ($13.3g/cm^2$), but 4% was the lowest at 75.18% ($22.2g/cm^2$). 4. The pH of Tofu was as follows: (a) in WPC, the value was WPC 6% > WPC 4% > WPC 2% > control and $CaCl_2$:GDL=6:4 > $CaCl_2$:GDL=8:2 > $CaCl_2$:GDL=9:1 > $CaCl_2$:GDL=7:3 and (b) in WP, WP 4% > WP 2% > control. 5. The ash content of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL=8:2 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=6:4 > $CaCl_2$:GDL=9:1 and (b) in WP, there was no difference between 2% and 4% addition. 6. The crude protein content of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL=8:2 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=9:1 > $CaCl_2$:GDL=6:4 and (b) in WP, there was no difference between 2% and 4% addition. 7. The crude fat content of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL=8:2 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=9:1 > $CaCl_2$:GDL=6:4 and (b) in WP, values decreased with increasing pressed weight. 8. The carbohydrate content of Tofu was as follows: (a) in WPC, the content was $CaCl_2$:GDL=8:2 > $CaCl_2$:GDL=7:3 > $CaCl_2$:GDL=6:4 > $CaCl_2$:GDL=9:1 and (b) in WP, values increased with increasing pressed weight. 9. The rheology test results of Tofu were as follows: (a) in WPC, hardness and brittleness was highest with $CaCl_2$:GDL=8:2 and 6% added WPC. Cohesiveness was highest with $CaCl_2$:GDL=6:4 and 2% added WPC. Elasticity was the highest with $CaCl_2$:GDL=7:3 and the added WPC control. (b) in WP, hardness was the highest with $22.2g/cm^2$ and added WP control. Cohesiveness was the highest with $17.8g/cm^2$ and added WP 2%. Elasticity was the highest with $17.8g/cm^2$ and added WP 4%. Brittleness was the highest with $17.8g/cm^2$ and added WP control. 10. The sensory test results of Tofu were as follows: (a) in WPC, the texture, flavor, color, and smell were the highest with $CaCl_2$:GDL=6:4 and 6% added WPC. (b) in WP, the texture was the highest in the control with $22.2g/cm^2$. Flavor and smell were the highest in WP 2% and $22.2g/cm^2$. Color was the highest in WP 2% and $17.8g/cm^2$. 11. The quality change of Tofu during storage was as follows: (a) in WPC, after 60 h, all samples began to get spoiled and their color changed, and mold began to germinate. (b) in WP, the result was similar, but the rate of spoilage was more rapid than that in the control.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.36-42
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• 2009

This study was performed to develop low-fat/reduced-salt sausages (LFRSS; <3% fat and <1.5% salt) containing milk protein (whey protein concentrate, WPC, or sodium caseinate, SC) that showed the similar cooking yield and textural characteristics to those of regular-fat/salt sausage control (RFC; 20% fat and 1.5% salt) or low-fat sausage control (LFC; <3% fat and 1.5% salt). Low-fat sausages (LFS) were formulated with a 2.5% fat replacer (konjac flour:carrageenan:soy protein isolate=1:1:3) and various salt levels (0.75, 1.0, 1.25, and 1.5%). LFS had differences in color and expressible moisture (EM, %) values as compared to those of RFC. A minimum salt level of 1% and addition of nonmeat proteins were required to manufacture LFRSS that have similar characteristics to those of RFC. However, LFS with 2% milk proteins reduced the hardness and gumminess as compared to LFC. These results indicated that 1% milk protein in combined with 1% salt was a proper level for manufacturing of LFRSS.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.648-657
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• 2018

The purpose of this study was to analyze the labeling of commercial protein bars in Korea and USA to develop Korean protein bars. Furthermore, we compared protein contents of products with daily protein intake, DRI, and AMDR. The protein bars were sampled in off- and on-line markets of both countries, with 17 in Korea and 113 in the US. As the results, since US products have bigger than one serving size than Korean ones, the intake of overall nutrients is higher, especially protein and sodium. Protein contents (per 100 g) of products in US were higher than those of Korea. The highest protein was soy protein isolate (SPI) in Korea and whey protein isolate (WPI) in the US. This is thought to be influenced by the preference and familiarity of food according to the country. In conclusion, since there are difference in eating habits, intake and preference of the protein source, it is necessary to develop suitable protein bars for Koreans. Therefore, this research provides the baseline of protein bars for consumers to choose products.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.587-593
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• 2008

Microbial exopolysaccharide (EPS) is a biothickener that can be added to a wide variety of food products, where it serves as a viscosifying, stabilizing, emulsifying, and gelling agent. The objective of this study was to investigate the optimum conditions of pH, incubation temperature, and whey protein concentration (WPC) for EPS production by Lactobacillus rhamnosus ATCC 9595. We found that maximal EPS production was achieved at a pH of 5.5 and temperature of $37^{\circ}C$. At the same fermentation conditions, EPS production was affected by the addition of L. rhamnosus GG (a weak-EPS producer). After growth for 24 hr, total EPS production was $583{\pm}15.4mg/L$ in the single culture system, and $865{\pm}22.6\;mg/L$ in the co-culture system with L. rhamnosus GG. Based on the presence of WPC, EPS production dramatically increased from $583{\pm}15.4$ (under no WPC supplementation) to $1,011{\pm}14.7\;mg/L$ (under supplementation with 1.0% WPC). These results suggest that WPC supplementation and the co-culture systems coupled with small portions of weak-EPS producing strain can play an important role in the enhancement of EPS production.