• Title, Summary, Keyword: soy gel

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Separation and Purification of Protease from Bacillus subtlils CCKS-111 in Korean Traditional Soy Sauce (한국재래간장으로 부터 분리한 Bacillus subtilis CCKS-111이 생성하는 Protease의 분리 및 정제)

  • Kim, Sung;Lim, Seong-Il;Lee, Hee-Duck;Lee, Seon-Ho;Son, Jun-Ho;Choi, Hee-Jin;Kim, Yeung-Hweal;Choi, Cheong
    • Applied Biological Chemistry
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    • v.40 no.3
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    • pp.178-183
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    • 1997
  • A protease was purified from Bacillus subtilis CCKS-111 by ammonium sulfate treatment, DEAE-cellulose ion-exchange chromatography, Sephadex G-100 gel filtration and high performance liquid chromatography (HPLC). The specific activity of the purified enzyme was 24.3 unit/mg protein and the purification fold of enzyme was 50.6. Molecular weight of the purified enzyme estimated about 28,000 by HPLC gel filtration. The amino acid residues of this enzyme were 251.3 except threonine, serine and glycine. This result was similar to Bacillus subtilis subtilisin DY. From the first N-terminal amino acid to the 32th amino acid, the amino acid sequence was estimated after RP-HPLC elution. N-terminal and the 32th amino acids were alanine and aspartic acid. Alanine, serine, glycine and arginine were four major acids in the enzyme.

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Enzymatic Modification of Soy Proteins: Effects of Functional Properties of Soy Isolate upon Proteolytic Hydrolysis (대두단백질(大豆蛋白質)의 효소적(酵素的) 변형(變形) : 분리대두단백질(分離大豆蛋白質)의 기능성(機能性)에 미치는 단백질가수분해(蛋白質加水分解)의 영향(影響))

  • Kang, Yeung-Joo
    • Korean Journal of Food Science and Technology
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    • v.16 no.2
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    • pp.211-217
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    • 1984
  • To study affinity of proteolytic enzymes to soy proteins, the physicochemical and functional properties of enzymatically modified protein products, kinetic parameters and degree of hydrolysis were measured using trypsin, alcalase (serine type protease) and pronase. Bacterial alcalase and pronase showed much greater affinity to soy protein than animal intestinal trypsin. This effect was very significant when unheated soy isolate was used as a substrate. Specific activities of these enzymes decreased with the increment of substrate concentration (over 2.0%, w/v) when heat denatured soy protein was used as a substrate. However, the decrease in specific activity was negligible at substrate concentrations lower than 2.0%. Polyacrylamide gel electrophoretic results showed that the pattern of 2S protein band changed distinctly in alcalase hydrolysis as compared with those of trypsin and pronase. Protein solubilities of alcalase and pronase hydrolyzates increased by 25-30%, at their pI (pH 5.0) over the control. Virtually no change was observed in solubility by trypsin hydrolysis. Heat coagulability and calcium-tolerance of the protein increased by enzymatic hydrolysis. No clear tendency, however, was observed for emulsion properties, foam expansion and the amount of free -SH groups. The enzyme treatment considerably decreased foam stability.

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Functional Properties of Soy Protein Isolate from Heat Treated Soybean (열처리 대두에서 분리한 대두 단백질의 기능성)

  • Yoon, Hye-Hyun;Jeon, Eun-Jae
    • Korean Journal of Food Science and Technology
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    • v.36 no.1
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    • pp.38-43
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    • 2004
  • Effects of heat treatment on functional properties of soy protein were examined. Soy protein isolate (SPI) was prepared from Korean soybean varieties, Manli and Taekwang, subjected to heat treatment at $60^{\circ}C$ for 30, 60, 90, and 120 min. pH-solubility results of SPI showed typical U-shape profiles with minimum solubility at pH 4-5 of isoelectric points of soy proteins, longer heat treatments showing slightly higher solubility. Water absorption, emulsifying activity, emulsion stability, and emulsion capacity of SPI increased, while oil absorption decreased, with heating time in Manli variety. Manli and Taekwang showed the highest emulsion capacities after 90-and 60-min heat treatments, respectively. Foam expansion of all SPIs increased with heating time up to 90 min. Texture profile analysis showed heat treatment up to 90 min significantly increased hardness, adhesiveness, springiness, gumminess, and chewiness, whereas significantly decreased cohesiveness of SPI gels (p<0.05).

Growth Inhibition of Listeria monocytogenes by Pure Compound Isolated from Extract of Morus alba Linne Bark (상백피 추출물중 Listeria monocytogenes 증식억제 물질의 분리 및 효과)

  • An, Eun-Young;Han, Ji-Sook;Shin, Dong-Hwa
    • Korean Journal of Food Science and Technology
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    • v.29 no.6
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    • pp.1236-1240
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    • 1997
  • The crude extract of Morus alba Linne bark which showed strong antimicrobial activity on Listeria monocytogenes was fractionated by some solvents and applied column chromatography for purification of active component. By silica gel column chromatography, active fraction (F-5') was purely isolated and confirmed their strong bactericidal effect on Listeria monocytogenes tested at level of 100 and 300 ppm in tryptic soy broth. The cell wall observed by SEM was abnormal after treatment of F-5'.

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Studies on the Changes of Taste Compounds during Soy Paste Fermentation (III) (된장 숙성 중 정미 성분의 변화에 관한 연구(III))

  • 김미정;이혜수
    • Korean journal of food and cookery science
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    • v.9 no.4
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    • pp.261-265
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    • 1993
  • For the purpose of supplying the information to improve the acceptability of soy paste as the condi-ment, the changes of peptide were determined. The results were as follows; Average peptide length were decreased. It was 102 at 0 day, 15 at 10 day and 4.1 at 180 day. Peptide fraction were the same as in 60 day and 180 day. Low molecular weight peptide were not changed greatly during fermention. Peptide identified in 180 day fermentation were Ala-Ser, Gly-Glu, Glu-Ser, Asp-Glu, Asp- Tyr, Asp-Ala-Ser, Ala-Ser-Glu, Glu-Ser-Ala, and Ala-Lys-Met. In the characteristics of bitter peptide in 180 day fermentation, soy paste itself didn't show bitter taste', solvent extration fraction I'showed bitter taste. After gel chromatography, fraction I, fraction II and fraction III were obtained and fraction II were bitter peptide of low molecular weight. After gel chromatography', solvent extration fraction 2'(water extration) were divided into fraction IV, V, VI,VII and VIII. Fraction IV, V and VI showed bitter taste. Amino acids composition of the fractions showing bitter taste were like that; fr. 1: Glu- (Asp, Pro, Val, lie or Leu)-Met fr. II Pro-(Glu, Val, Phe)-lle or Leu fr. IV: Glu-(Asp, Ala, Tyr, Leu of lie)-Phe fr. V: Ala-(Met, Glu, Pro)-lle or Leu fr. VI: Asp-(Phe, Ser, fly)-Val.

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Effect of Dry Heating on the Pasting/retrogradation and Textural Properties of Starch-soy Protein Mixture (건조가열이 전분과 콩단백질 혼합물의 호화 및 노화특성과 조직감에 미치는 영향)

  • Lee, Ki-Jung;Lee, Su-Yong;Kim, Yong-Ro;Park, Jang-Woo;Shim, Jae-Yong
    • Korean Journal of Food Science and Technology
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    • v.36 no.4
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    • pp.568-573
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    • 2004
  • Effects of dry heating and pH on pasting, thermal, and textural properties of corn starch containing soy protein isolate (SPI) were investigated. Samples were prepared by drying corn starch dispersions containing 3% SPI at $40^{\circ}C$ (unheated sample) or additionally heating dried mixtures at $130^{\circ}C$ (heated sample). Pasting properties of starch samples and textural properties of starch gels were measured using Rapid Visco-Analyzer (RVA) and Texture Analyzer (TA), respectively. Effects of SPI addition and dry heating on retrogradation and microstructure of gel samples were investigated using DSC and SEM, respectively. Pasting viscosity of dry-heated samples was significantly higher than that of unheated samples, and at pH 8 compared to pH 6. Dry-heat treatment decreased fracture stress and strain of starch gels containing SPI. No significant effects of dry-heat treatment and pH were observed on retrogradation of starch gels. Addition of SPI retarded starch retrogradation and modified starch gel properties with increased nutritional value. Dry-heat treatment with SPI could be possible method for starch modification.

Changes of Protein Profiles in Cheonggukjang during the Fermentation Period (전통 청국장의 발효 기간 동안 변화하는 수용성 단백질 개요)

  • Santos, Ilyn;Sohn, Il-Young;Choi, Hyun-Soo;Park, Sun-Min;Ryu, Sung-Hee;Kwon, Dae-Young;Park, Cheon-Seok;Kim, Jeong-Hwan;Kim, Jong-Sang;Lim, Jin-Kyu
    • Korean Journal of Food Science and Technology
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    • v.39 no.4
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    • pp.438-446
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    • 2007
  • The fermented soybean product, cheonggukjang, is favored by many people, partly due to its bio-functional ingredients. Since the fermentation process of cheonggukjang is mediated by enzymes, including proteases, produced by microbes, analysis of the proteome profile changes in cheonggukjang during fermentation would provide us with valuable information for fermentation optimization, as well as a better understanding of the formation mechanisms of the bio-functional substances. The soluble proteins from cheonggukjang were prepared by a phenol/chloroform extraction method, in order to remove interfering molecules for high resolution 2-D gel analysis. Proteomic analysis of the cheonggukjang different fermentation periods suggested that most of the soluble soy proteins were degraded into smaller forms within 20hr, and many microbial proteins, such as mucilage proteins, dominated the soluble protein fraction. The proteomic profile of cheonggukjang was very different from natto, in terms of the 2-D gel protein profile. Among the separated protein spots on the 2-D gels, 50 proteins from each gel were analyzed by MALDI-TOF MS and PMF for protein identification. Due to database limitations with regard to soy proteins and microbial proteins, identification of the changed proteins during fermentation was restricted to 9 proteins for cheonggukjang and 15 for natto. From de novo sequencing of the proteins by a tandem MS/MS, as well as by database searches using BLASTP, a limited number of proteins were identified with low reliability. However, the 2-D gel analysis of proteins, including protein preparation methods, remains a valuable tool to analyze complex mixtures of proteins entirely. Also, for intensive mass spectrometric analysis, it is also advisable to focus on a few of the interestingly changed proteins in cheonggukjang.

Purification and Characterization of a Fibrinolytic Enzyme Produced from Bacillus amyloliquefaciens K42 Isolated from Korean Soy Sauce. (한국재래간장에서 분리한 Bacillus amyloliquefaciens K42가 생산하는 혈전용해효소의 정제 및 특성)

  • 윤경현;이은탁;김상달
    • Microbiology and Biotechnology Letters
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    • v.31 no.3
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    • pp.284-291
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    • 2003
  • Bacillus amyloliquefaciens K-42, which produces strongly a fibrinolytic enzyme, Was isolated from Ganjang, a traditional Korean soy sauce. The fibrinolytic enzyme was purified to homogeneity by ammonium sulfate fractionation, ion-exchange chromatography on DEAE-Sephadex A-50, gel chromatography on Sephadex G-100, and gel chromatography on Sephadex G-75 of the culture filtrate of Bacillus amyloliquefaciens K42. The purified enzyme showed the specific activity of 59.4 units per milligram, which was increased by 17.1 fold over the culture broth. And the molecular weight of purified fibrinolytic enzyme was confirmed to be about 45,000 Dalton by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme activity was relatively stable at pH 4.0-10.0 and the optimum pH was 8.0. The activity of the purified enzyme was increased by $Mg^{2+}$ , Cu$^{2+}$ but the enzyme was totally inhibited by $Ba^{2+}$ $Hg^{2+}$ In addition, the enzyme activity was potently inhibited by EDTA, EGTA and CDTA. It was concluded that the purified enzyme was a metalloprotease. And Km value was 2.03 mg/ml to fibrin.

Identification of Lactic Acid Bacteria from Meat by Low Molecular Weight(LMW) RNA Profiles (Low Molecular Weight(LMW) RNA Profiles에 의한 젖산균의 동정)

  • Cha, Woen-Suep
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.21 no.6
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    • pp.681-685
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    • 1992
  • Low molecular weight RNA(LMW RNA : 5S rRNA and tRNAs, <150 nucleotides) profiles of several bacteriocin production lactic acid bacteria from pig meats and reference lactic acid bacteria were generated on 10% denaturing polyacrylamide gel electrophoresis. Data evaluation including three molecular weight markers enabled the calculation of relative nucleotide units(RNU) for every band. Gels profiles and RNU evaluations were effective for identification of lactic acid bacteria species. LMW RNA profiles of lactic acid bacteria showed no variation in dependence on APT(All Purpose Tryptone Broth), TSB(Tryptic Soy Broth), MRS(Lactobacilli MRS Broth) different cultural medium.

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Effect of Hydration Condition of Non-Muscle Protein on Gelling (비근육 단백질의 수화조건이 겔 형성에 미치는 영향)

  • Cho Min Sung;Lee Nahm Gull;Cho Young Je
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.6
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    • pp.627-632
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    • 2002
  • This study was investigated the changes of gel properties about pH, color and water holding capacity at various hydration time and temperature of food-grade additives (BPP: bovine plasma protein, DEW: dried egg white, SPI: soy protein isolate). The changes of rheological properties were checked about hydration time and temperature. Hydration time and temperature affected pH value, hydration decreased pH of SPI and DEW. The BPP was not influenced at hydration time and temperature. Some Hydration condition increased jelly strength of food-grade additive, but SPI did not form a gel at all hydration condition. Hydration increased lightness of food-protein.