• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.53-58
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• 1996

The characterstics of the soy protein curd(eczyme-, HCI- and Ca-surd) were shown by scanning electron micrographs and gel electrophoreis. The emulsion stability of enzyme-curd showed high value in the range of pH 2~10and wide range of temperature(20~8$0^{\circ}C$). While at the isoelectric point(pH5.0), the emulsion stability of the HCI-and Ca-curd was decreased remarkably, and the emulsion stability of temperature was reduced quickly to the 60% and 40% at the 4$0^{\circ}C$. The foam stability of enzyme-curd was slightly higher than that HCI-and CA-curd in all ranges of pH and temperature. The feature of SEM of enzyme-cured produced degradation products faster than that of the HCI- and Ca-curd.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.973-979
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• 1994

Microorganisms, including the strain IJ-3 isolated from soil, were found to secrete an extracellular soybean protein coagulating enzyme and the strain, IJ-3 was identified as Genus Bacillus according to the Bergey's manual . The enzyme coagulated protein in soymilk , thus forming a curd at pHs 5.8-6.4 and at 55-75℃. The optimum temperature for soybean protein coagulating activity was 65-75℃ and the enzyme was stable at temperature below 50℃ and was found to be stable with about 60-100% of the original activity at a with pH ranges(pH6-7). The molecular weight of enzyme was estimated to be 28,000 by SDS-PAGE. The curd formed with the enzyme from Bacilus sp. IJ-3 has a smooth texture, and a mild taste without any bitterness or a beany flavor.

• Culinary science and hospitality research
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• v.3
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• pp.327-341
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• 1997

Food materials usually contain much water, and thus are susceptible to decay be enzyme and microorganism. Cereals are usually consumed as staple food, but they have low protein content. Protein is a major component of body, and should be consumed as a nutrient for all ages. Animal protein like chicken and vegetable protein such as bean curd and soybean and good sources of high quality protein. Bean curd is a traditional food which have good nutrients, and so various cooking methods are needed to be developed for the supplement of high quality food. 1) Cereals such as rice, barley, and bean curd, soybean, green vegetables, tangle and brown seaweed are known as food for long life. 2) Soybean is able to suppress the formation of hydroperoxide by saponin and lecithin. 3) Curd in bean curd means soft in Chinese character, and bean curd may be the mother of cheese. 4) Bean curd have high nutrition and digestibility. As soybean is dipped longer in water for bean curd, the production rate is higher. 5) There are many kinds of bean curd products, and can be purchased inexpensively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.5
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• pp.643-649
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• 1993

Soybean composition, which is different from those of other beans and grains, gives from 35 to 40 percent protein, 15 to 20 percent oil, and 20 to 25 percent sugar. Soybean has been extensively used as the raw material for traditional foods such as bean curd, soy sauce, soy paste and so on, since ancient times in Korea. Ultracentrifugal components of the soybean proteins represent four major peaks with sedimentation constants of about 2, 7, 11 and 15S. The two major reserve protein of soybean, 7S and 11S globulins, have been isolated and characterized by many works. The curd made with microbial enzyme exhibited minuter structure than those of the metal ion-and acid-treatment. Thus, the curd obtained by enzymatic operation serves as a material for further development of food items, and the procedure may by widely applicable in food processing.

• Preventive Nutrition and Food Science
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• v.2 no.3
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• pp.259-262
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• 1997

The microstructures of soybean milk curds, prepared by different coagulation methods, were observed by the scaning electron microscope. Th curd coagulated by theaddition of bacerial soybean mil clotting enzyme showed little textural changes and gave smoother gel than those prepared either by lactic acid fermentation using Streptococcus thermophilus or by the addition of CaSO$_4$. The curds obtained by lactic acid fermentation and by the addition of inorganic salt exhibited three dimensional network structure which indicated harder gel than that prepared by soybean mil clotting enzyme.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.10
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• pp.1369-1379
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• 2010

This study investigated purification and milk-clotting activity of the enzymes produced by Bacillus subtilis var, natto and Rhizopus oligosporus compared with that of commercial rennet. The clotting time, viscosity, tension and microstructure of the curd and electrophoretic patterns of milk proteins were determined. The milk-clotting activity/proteolytic activity ratios (MCA/PA ratio) of B. subtilis, R. oligosporus and commercial rennet were also compared. The results revealed that the curd formed by the commercial rennet had the highest viscosity and curd tension and the shortest clotting time among the three enzymes. However, curd produced by Rhizopus enzymes was ranked as second. From the MCA/PA ratio and electrophoretogram analyses it could be concluded that the enzyme produced by B. subtilis had the highest proteolytic activity, while the commercial rennet had the highest milk-clotting activity. Observations of microstructures of SEM showed that the three-dimensional network for curd formed by commercial rennet was denser, firmer and more smooth. The milk-clotting activity, specific activity, purification ratio and recovery of the purified enzymes produced by both the tested organisms were also determined with ion exchange chromatography and gel filtration.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.904-909
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• 2005

To produce functional food ingredient from the soybean curd residue (SCR), alkaline fermentation was performed with SCR from cold processed (D-SCR) or hot processed (P-SCR) tofu. The solid- state fermentation was performed by Bacillus firmus NA-1 at $42^{\circ}C$. The fermentation of heat-treated D- SCR resulted in higher production of peptides and fibrinolytic enzyme compared with D-SCR without heating. The P-SCR showed higher production of peptides, fibrinolytic enzyme, indicating alkaline pH after fermentation for 18 hr. When the moisture content of P-SCR was reduced to $60\%$, the production of peptides and fibrinolytic enzyme were enhanced. The P-SCR fortified with $10\%$ MFS (micronized full-fat soy flour) showed higher fibrinolytic enzyme activity and consistency index by fermentation of Bacillus firmus NA-1 Furthermore, the P- SCR fortified with $20\%$ MFS indicated relatively higher peptide content, fibrinolytic enzyme activity and enhanced flavor. By increasing the addition of MFS, the peptide content of fermented P-SCR was increased significantly, but fibrinolytic enzyme was slightly decreased.

• Preventive Nutrition and Food Science
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• v.7 no.4
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• pp.397-404
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• 2002

Soybean curd residue (SCR) was fermented by lactic acid bacteria, Lactobacillus rhamnosus LS and Entercoccus faecium LL, isolated from SCR. The pH, titratable acidify and viable cell counts were determined from the fermented SCR to evaluate the lactic acid production and growth of lactic acid bacteria. Optimal amounts of pretense enzyme and glucose, and ideal fermentation time for SCR fermentation were estimated by response surface methodology (RSM). Raw SCR fermented by indigenous microorganisms had 0.78 % titratable acidity, The acid production in SCR fermented by L. rhamnosus LS was greatly enhanced by the addition of glucose and lactose. However only glucose increased acid production by Ent. faecium LL. The proof test of SCR fermentation demonstrated that similar results for titratable acidity, tyrosine content and viable cell counts to that predicted could be obtained by the at optimized fermentation conditions. In the presence of 0.029 % (w/w) pretense enzyme and 0.9% (w/w) glucose, the SCR fermented by Ent. faecium LL showed 1.07% (w/v) of titratable acidity, 1.02 mg% tyrosine content and 2$\times$10$^{9}$ (cfu/g) of viable cell counts. With the SCR fortified with 0.033% pretense enzyme and 1.7% glucose, L. rhamnosus LS showed 1.8% (w/v) of titratable acidity, 0.92 mg% of tyrosine content and 2$\times$10$^{9}$ (cfu/g) of viable cell counts.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1470-1476
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• 2001

Kou Woan Lao is an oriental-style dairy product, which is coagulated by milk-clotting enzyme from the culture filtrate of lao-chao. The product appears smooth, sweet, slightly wine flavour, and the flavour differs from yogurt. The aim of this study was to search for the optimum model to shorten the period of manufacture, and to improve the quality of Kou Woan Lao. A response surface design was used for studying the effects of addition of carrageenan, locust bean gum, and culture filtrate from lao-chao on the curd firmness, viscosity, and syneresis. Results indicated that the best rheological property, preservative quality and acceptability of Kou Woan Lao could be obtained by the combination of 0.22% carrageenan, 0.21 % locust bean gum and 12% culture filtrate from lao-chao. The curd firmness, viscosity and syneresis of resultant product were 29.3 g, 21,347.7 cps, and 8.92%, respectively and the microstructure of the curd revealed a relatively complete three-dimensional spider web-like structure.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.294-299
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• 1992

This study was to examine the effect of functional properties of soy protein isolate(SPI) and qualities of soybean curd upon proteolytic hydrolysis. SPI was hydrolyzed using proteolytic enzyme, bromelain. The protein content of SPI by microkjeldahl method was 84% and the degree of hydrolysis in modified soy protein isolate(MSPI) was 2.7%. The solubility of MSPI was higher than that of control at various pH tested and proteolytic hydrolysis was increased emulsion formation and foam expansion while decreased emulsion stability, foam stability and calcium precipitation. Modified soybean curdI, standard soybean milk: Modified soybean milk=3:1, was soft and springy soybean curd when the texture properties of soybean curd were tested by texture profile analysis using Instron and sensory evaluation. The rheological model of soybean curds was investigated by stress relaxation test. The analysis of relaxation curve revealed that the rheological behavior of soybean curds could be expressed by 7-element generalized Maxwell model. The equilibrium modulus and modulus of elasticity decreased as the ratio of modified soybean milk was increased.