• Title, Summary, Keyword: soybean curd whey

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Improvement on Textural Properties of Soybean Curd by Freeze Denaturation of Soybeans (대두의 동결처리에 의한 두부의 텍스쳐 특성의 증진)

  • Baik, Sang-Ho;Kim, Myung-Kon;Yun, Sei-Eok;Joo, Hyun-Kyu
    • Korean Journal of Food Science and Technology
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    • v.28 no.2
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    • pp.267-272
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    • 1996
  • Effect of freezing of soybeans on instrumental and sensory textures of soybean curd was investigated. The hardness, gumminess and chewiness of soybean curd prepared with frozen soybeans were about three times as high as those prepared with unfrozen soybeans, while cohesiveness and elasticity were affected little by freezing. Sensory evaluation showed that freezing improved the quality of soybean curd. Instrumental and sensory textures of soybean curd prepared with frozen soybeans were excellent and almost same regardless of the boiling time when the soy slurry was boiled for 2.5 min or 5 min. However, the textures of soybean curd prepared with unfrozen soybeans were deteriorated by reducing the boiling time to 2.5 min. It was postulated that freezing facilitate the heat-denaturation of soyprotein to enhance aggregation of soy proteins and formation of cross-linkage between aggregate and $Ca^{++}$. Frozen soybeans resulted in soybean curd which lower fat content, while protein content of soybean curd was almost he same. Frozen soybeans gave a lower yield of soybean curd, which is supposed to be caused by the more fat loss during whey-off.

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Changes in Isoflavone Content and Mass Balance During Soybean Processing

  • Han, Jin-Suk;Hong, Hee-Do;Kim, Sung-Ran
    • Food Science and Biotechnology
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    • v.16 no.3
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    • pp.426-433
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    • 2007
  • We analyzed the isoflavone content of domestic soybeans during steaming, boiling, fermentation, germinating cultivation, fermentation, and soybean curd production. The isoflavone content of the beans was reduced by steaming and boiling, and overall reductions ranging from 16.0 to 65.0% of initial isoflavone values were detected. After 4 days of germinating cultivation, the total isoflavones of Eunhakong increased from 1,341 to $2,017\;{\mu}g/g$ and the total isoflavones of Guinunikong increased from 1,284 to $1,535\;{\mu}g/g$. The isoflavone content of the vinegar beans produced from Hwangkeumkong and Black No.1 increased from 1,877 to $1,956\;{\mu}g/g$, and from 885 to $1,956\;{\mu}g/g$ after 8 days of immersion in 4% acetic acid, respectively. During soybean curd production, significant amounts of isoflavones were lost in the whey (30-31 %) and soybean curd residue (15-20%). Only 37.4% of the isoflavones present in the original soybeans remained in the soybean curd with the hot extraction method, and 50.7% of them with the cold extraction method. Soybean curd prepared with whole soybean method, however, retained 80.7% of the initial isoflavones.

Utilization of Soybean Curd Whey as a Medium for Lactobacillus acidophilus and Acid-and Bile-tolerance of Cultured Strains (순물의 Lactobacillus acidophilus 배지로서으 이용 및 생육균주의 내산성과 내담즙산성)

  • Chung, Soo-Hyun;Suh, Hyung-Joo;Lee, Ho
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.5
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    • pp.872-877
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    • 1997
  • Soybean curd whey(SCW) containing plenty of nutrients is the discarded by-product in soybean curd processing. To test the potential utilization of SCW as a medium for the cultivation of Lactobacilus acidophilus, the chemical composition of SCW, as well as the growth, acid production, acid-tolerance, and bile-tolerance of L. acidophilus in SCW-based media were investigated. Sucrose and stachyose, the main free sugars of SCW, were 0.42% and 0.41%, respectively. SCW contained 36.1mg/L of total free amino acids. L. acidophilus KFRI 150 showed lower cell growth and acid production in SCW than those in MRS broth. In optimized SCW-based medium supplemented with 1.0% glucose, 0.5% yeast extract, and 0.2% $K_{2}HPO_{4}$, the growth and acid production of L. acidophilus KFRI 150 increased by twice against those in SCW. In optimized SCW-based medium, the viable counts of four L. acidophilus strains were mostly at the level of $10^{9}$/ml, which is similar to those in MRS broth. Each acid-tolerance and biletolerance of four L. acidophilus strains cultured in optimized SCW-based medium and MRS broth showed no dist-inguishable difference.

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Soybean Whey Composition and Alcohol Fermentation by Using Saccharomyces Cerevisiae (두부폐액(廢液)의 조성(組成) 및 Saccharomyces Cerevisiae를 이용(利用)한 Alcohol 발효(醱酵))

  • Choi, Mi-Ae;Choi, Kyoung-Ho
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.11 no.2
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    • pp.31-35
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    • 1982
  • Alcohol fermentation was carried out by using the yeast (S. cerevisiae) and soybean whey as the sole carbon source. The whey was gained form waste after manufacturing of soybean curd. The whey contained approximately one gram sugar per hundred mililter and the sugar was consisted of a 65 per cent of reducing sugar. However, it showed a low protein content of 43mg per the same volume. Ammonium sulfate showed the best effect on the generation of carbon dioxide among three kinds of tested nitrogen sourogen sources, potassium nitrate, urea and ammonium sulfate. Thus, fermentation was carried out with supplement of 2.0g ammonium sulfate to one liter of soybean whey. During fermentation continued for 48 hours, the maximum amount of ethanol 1.86g was produced from one liter of soybean whey. The ethanol fermentation utilized 81 and 94% of its initial sugar and protein contents, respectively.

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Factors Influencing the Removal of Water Soluble Solids from Soybean Curd Whey by Reverse Osmosis (역삼투법을 이용한 두부순물의 가용성 물질 제거에 관한 연구)

  • Kim, Dong-Man;Baek, Hyung-Hee;Jin, Jae-Soon;Lee, Sei-Eun;Kim, Kil-Hwan
    • Korean Journal of Food Science and Technology
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    • v.24 no.4
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    • pp.306-310
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    • 1992
  • The effects of membrane type, temperature and pH on the permeate flux and removal of soluble solids from soybean curd whey by reverse osmosis were studied at recommended pressures for optimum performance of the membranes. The fluxes obtained with HR 95 and HR 98 membranes at 60 bar were not lower than that with CA 930 membrane at 20 bar. Soluble solid content in the permeate increased to 1.5 Brix after 90 min by CA 930 membrane, as opposed to 0 Brix with the HR 95 and HR 98 membranes. Permeate flux was increased by 28.4% as operation temperature increased from $30^{\circ}C$ to $50^{\circ}C$. COD of the whey was rejected up to 80.5%, 99.7% and 99.5% by using the membranes of CA 930, HR 95 and HR 98, respectively. pH adjustment of the whey resulted in decreasing membrane performance. But the rejection rate of COD in permeate with HR 98 membrane was slightly increased to 99.9% when the pH was adjusted to 7.0.

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Functional Properties of Sunmul (Soybean Curd Whey) Concentrate by Ultrafiltration (한외여과에 의한 순물 농축액의 기능적 특성)

  • Kim, You-Pung;Eom, Sang-Mi;Chang, Eun-Jung;Kim, Woo-Jung;Oh, Hoon-Il
    • Korean Journal of Food Science and Technology
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    • v.38 no.4
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    • pp.488-494
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    • 2006
  • This study was carried out in order to investigate the feasibility of utilizing concentrated sunmul (soybean curd whey), which is a waste by-product of soybean curd processing, as a functional food ingredient. Sunmul Powder was concentrated by ultrafiltration and spray dried with or without dextrin. Oil adsorption capacity of UF retentate powder was similar to that of ISP (Isolated Soy Protein) and higher than that of sunmul powder, whereas water holding capacity of UF retentate powder was lower than that of ISP. Protein solubility of all types of UF retentate powder was significantly higher than that of ISP at pH 2.0-10.0 with the lowest protein solubility seen at pH 4.0 and solubility increasing as the conditions became more acidic or alkaline. Emulsifying activity indexes of UF retentate powder at pH 2.0-10.0 were not influenced by pH. Emulsion stability of 4% sunmul solution was lowest at pH 4.0, but that of UF retentate powder was higher at acidic pH values and decreased with increasing pH. Foaming capacities of sunmul and UF retentate powder were high at pH 4.0-6.0, but the foam of UF retentate powder disappeared within 20 minutes in all conditions of pH.

Coprecipitation Characteristics of Cheese Whey and Soybean Proteins (유청(乳淸)과 대두 단백질(蛋白質)의 공동침전(共同沈殿) 특성(特性))

  • Wee, Jae-Joon;Lee, Hyong-Joo
    • Applied Biological Chemistry
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    • v.26 no.4
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    • pp.199-204
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    • 1983
  • As a way of utilizing cheese whey to fortify sulfur-bearing amino acids to soybean protein, whey-soybean coagulum was made from whey-soy milk mixture and optimum conditions for coprecipitation of the two proteins were determined. Mixture of whey and soymilk in 1 : 1 volume ratio was coagulated at $0.005{\sim}0.5M$ of $CaCl_2$ concentration, pH $1.5{\sim}8.0$, and at $60{\sim}100^{\circ}C$, and absorbance at 500nm of filtrate from the coagulum was measured. Optimum conditions for the coprecipitation were 0.0125M of $CaCl_2$ concentration, pH $6.5\sim7.5$, and $70{\sim}80^{\circ}C$ which resulted in the minimum absorbance and also good physical properties of the curd.

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Textural Characteristics and Microstructure of Soybean Curds Prepared with Different Coagulants (응고제를 달리하여 제조한 두부의 질감과 구조 특성)

  • Lee, Hun-Joo;Hwang, In-Kyeong
    • Korean journal of food and cookery science
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    • v.10 no.3
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    • pp.284-290
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    • 1994
  • To prepare soybean curds, the concentration of $CaCl_2,\;MgCl_2,\;CaSO_4$ and glucono-%{\delta}$-lactone fresh solution as coagulants were determined by transmittance of whey using spectrophotometer. The concentrations of four coagulants at which the transmittance had the highest value were chosen. Moisture content, yield and protein recovery of soybean curds prepared with four coagulants were investigated. The textural properties were examined by Instron Universal Testing Machine, and sensory evaluation was carried out. The microstructure of soybean curds was examined by SEM. Soybean curds obtained with $CaCl_2\;and\;MgCl_2$ were hard and coarse, and had roasted nutty taste, whereas those with $CaSO_4$ and GDL revealed very smooth, soft and uniform. Soybean curd prepared with GDL had the lowest acceptability because of sour taste. The texture and acceptability of soybean curds were influenced by the type of coagulant.

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Stability of Protein Colloids in the Mixture of Cheese Whey and Soy Milk (유청(乳淸) 및 두유(豆乳) 혼합액에서의 단백질 콜로이드 안정성)

  • Shon, Dong-Hwa;Lee, Hyong-Joo
    • Applied Biological Chemistry
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    • v.29 no.1
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    • pp.83-89
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    • 1986
  • To investigate effectors on the colloidal stability of whey and soybean proteins, characteristics of tofu-gel formation, effects of heat treatment and salt composition on the colloidal stability, and effects of heat treatment on storage stability were analyzed. When experimental tofus were made from the mixture of whey and soybean, the calcium in the whey precipitated the soy proteins, and disrupted the gel formation, which resulted in the curd of poor texture. In the heat treatment at $60{\sim}100^{\circ}C$, whey and the whey proteins dialyzed against distilled water were readily preciptated at over $70^{\circ}C$, but the mixture of whey and soy extract as well as soy extract were stable at the range of temperature. The proteins of soy extract, whey dialyzed against sodium phosphate buffer, and the mixture were stable at the same heat treatment, and this suggested that phosphates in the soy extract stabilize specialty the whey proteins. Soy proteins were easily destabilized by adding $CaCl_2(0.05{\sim}0.07M)$ at $80{\circ}C$ and $70{\sim}85%$ of the proteins in soy extract and the mixture were preciptated, while only $30{\sim}55%$ of the proteins in whey dialyzed against distilled water were destabilized at the same conditions. Storage stability at $4^{\circ}C$ of the mixture was increased when the mixture was treated at $63^{\circ}C$ and lower temperature.

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