• Title, Summary, Keyword: soybean curd whey

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Physicochemical and Sensory Characteristics of Dongchimi Added with Soybean-Curd Whey (두부순물 첨가 동치미의 이화학적.관능적 특성)

  • 김미리;김민정;백종연
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.6
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    • pp.1068-1075
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    • 2001
  • Effect of soybean-curd whey on the dongchimi fermentation was investigated by measuring physicochemical and sensory characteristics during fermentation at 1$0^{\circ}C$. Dongchimi was prepared with various levels (0, 2, 5, and 10%) of soybean-curd whey. During fermentation, whereas salt concentrations of dongchimi liquid (1.1 ~ 2.0%) were similar among treatments, greater decrease in pH, but greater increase of total acidity, reducing sugar content, number of lactic acid bacteria and turbidity were observed in dongchimi with soybean-curd whey than those of control from the 2nd to the 9th day of fermentation. But at the 16th day of fermentation, acidity, turbidity and number of lactic acid bacteria of dongchimi with soybean-curd whey were similar to those of control. Reducing sugar content of soybean-curd whey addition groups maintained higher than that of control. The Hunter color L value decreased gradually and that of dongchimi with soybean-curd whey was lower than that of control. b value of control increased, but soybean-curd whey addition groups decreased during fermentation. Hardness and fracturability, determined by texture analyser, were higher in soybean-curd whey addition groups than control. Sensory evaluation showed that the scores of turbidity, sweet taste, savory taste, hardness and over-all preference were significantly higher in soybean-curd whey addition groups than control (p<0.05) ; the highest with 5% soybean-curd whey addition followed by 2% addition. dongchimi with 5% soybean-curd whey addition was the most preferable one with the score of 6.5.

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Isoflavone Contents and Antioxidative Effects of Soybeans, Soybean Curd and their By-Products (콩, 두부 및 두부부산물중의 Isoflavone함량 및 항산화효과)

  • 배은아;권태완;문갑순
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.3
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    • pp.371-375
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    • 1997
  • The content of genistein and daidzein which were known to be major antioxidative compounds in soybeans were detected by $C_{18}$ reverse phase HPLC. Most of isoflavones in soybeans were detected in the methanol extract but much less amount of isoflavones in the water extract. Among the four different kind of soybeans, the isoflavone content was highest in brown soybean, followed by yellow, small black and black soybean, in the order. These isoflavones were known to be soluble in hot water, which means transfer of isoflavone content was highest in brown soybean, followed by yellow, small black and black soybean, in the order. These isoflavones were known to be soluble in hot water, which means transfer of isoflavones in soy curd into whey during soy curd processing. To identify the change of isoflavone content during processing of soybean curd, soybean curd were made from yellow, brown and black soybean and isoflavone content were determined in each soybean curd, curd residue and whey. Most of soflavones were remained in the whey, it means most of useful antioxidative compounds were wasted. Thus, it is necessary to develop new technology to collect these isoflavones lost during soybean curd processing.

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Quality Characteristics and Antioxidant Activities of Soybean Curd Products Containing Small Black Soybean (쥐눈이콩을 첨가한 두부제조에 따른 두부, 비지 및 순물의 항산화성)

  • Kim, Joon-Hee;Lee, Young-Tack
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.11
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    • pp.1431-1435
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    • 2007
  • Soybean curds were prepared by adding different levels (20, 40, and 60%) of small black soybean, and the quality characteristics of the soybean curds were investigated. The yield of soybean curd increased slightly with the increment of the levels of small black soybean, whereas L value (lightness) and b value (yellowness) decreased. Analysis of textural properties demonstrated that the addition of small black soybean lowered the hardness and chewiness of soybean curd, while it slightly increased the cohesiveness and adhesiveness. Antioxidant activities of soybean curd, soybean curd residue, and soybean curd whey were estimated by determining electron donating ability (EDA) to DPPH radical and superoxide dismutase (SOD)-like activity. These activities in all of the samples increased with the addition of small black soybean, especially in soybean curd residue and soybean curd whey; also, soybean curd whey containing small black soybean showed the highest activities.

Texture Characteristics of Soybean-Curds Prepared with Different Coagulants and Compositions of Soybean-Curd Whey (응고제를 달리하여 제조한 두부의 텍스쳐 특성과 두부순물의 성분)

  • 이선미;황인경
    • Korean journal of food and cookery science
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    • v.13 no.1
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    • pp.78-85
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    • 1997
  • To determine the optimum coagulants concentrations for preparing soybean-curds, the transmittance of soybean-curd whey using spectrophotometer has been measured. The textural properties of soybean-curds were examined by texture analyzer and sensory evaluations. The general components, oligosaccharides and amino acids in soybean-curd wheys were analyzed. Protein patterns of soybean-curd wheys comparing with soyflour and soymilk were investigated. By texture analyzer, hardness, cohesiveness, springiness, and gumminess of Cacl$_2$ soybean-curd, MgCl$_2$ soybean-curd were higher than those of CaSO$_4$ soybean-curd and GDL soybean-curd. In the sensory evaluations, CaSO$_4$ soybean-curds and GDL soybean-curds were smoother and moister than others. Glutamic acid and aspartic acid were the first two abundant amino acids in three kinds of soybean-curd wheys, but arginine was the most abundant amino acid in GDL soybean-curd whey. Total sugar content of soybean-curd wheys were about 12-13 g/l, and the main sugars among 5 kinds of sugars were sucrose and raffinose. Electrophoresis using SDS-PAGE showed that glycinin and P-conglycinin, the main proteins of soybean appeared in soy flour and soymilk, and only low molecular weight subunits appeared in soybean-curd wheys.

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Physico-chemical Properties of Soybean Curd Whey Concentrated by Reverse Osmosis (역삼투법으로 분리, 농축한 두부순물의 이화학적 특성)

  • 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.311-314
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    • 1992
  • Several Physico-chemical properties of the retentate obtained from reverse osmosis of soybean curd whey were studied. The contents of sucrose, raffinose and stachyose in the retentate were 32.59%d.b., 4.76%d.b. and 9.99%d.b., respectively. Potassium (5.23%d.b.), in the retentate was a dominant element in ash. Protein content (18.69%d.b.), amino acid composition and subunit pattern of protein in PAG-electrophoresis were somewhat different from those of the soybean protein. Emulsification activity, emulsification stability and viscosity of protein isolated from soybean curd whey (WPI) were slightly inferior compared to protein isolated from soybean (SPI), with the exception of solubility that depended on the pH of WPI.

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Changes in Soluble Sugars and Soybean Curd Yield with Increased Steeping Time during Soybean Curd Processing (두부제조시(豆腐製造時) 대두(大豆)의 수침시간(水浸時間)에 따른 수용성당류(水溶性糖類) 및 두부수율(豆腐收率)의 변화(變化))

  • Choi, Kwang Soo;Kim, Soon Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.12 no.4
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    • pp.401-406
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    • 1983
  • Changes in the soluble sugar content contained in the soybean, soybean milk, soybean curd and soybean whey were determined to investigate the method of reducing the introductions of soluble oligosaccharides like sucrose, raffinose and stachyose, which cause flatulence in human, to soybean curd from soybean by extending the soaking time of soybean. The soybean curd yields according to the extention of the soaking time were also determined. Markedly increased glucose, slightly reduced fructose and sucrose and noticeably reduced raffinose in soybean milk were observed with extended soaking time. Most of sucrose, raffinose and all of maltose were transferred to soybean whey. Gradual increase of soybean curd yields were obtained by extending soaking time within the experimental conditions.

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Isolation of Photosynthetic Bacteria and the Cell Growth on Soybean-Curd Whey Wastes (광합성 세균의 분리 동정 및 두부 유청 폐수에서의 배양조건 검토)

  • Ji, Geun-Eog;Lee, Ke-Ho
    • Korean Journal of Food Science and Technology
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    • v.25 no.2
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    • pp.142-147
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    • 1993
  • For the purpose of fixing solar energy and utilizing water wastes from food industries for SCP(single cell protein), 170 strains of photosynthetic bacteria were isolated from 56 samples. Among 170 strains, B-Ps-106 strain was selected as the most suitable strain and identified as a variant or a relation of Rhodopseudomonas sphaeroides and its growth was better under anaerobic light condition than aerobic condition. The optimum conditions of the cell growth of B-Ps-106 were investigated on soybean-curd whey media. The optimum pH for cell growth was $8.5{\sim}9.0$. The optimum temperature was $30^{\circ}C$ and the optimum light density was above $0.72\;cal/cm^2/min$. The most favorable concentration of $K_2HPO_4\;and\;(NH_4)_2SO_4$ was both 0.9 g/l when added to soybean-curd whey media.

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Ultrafiltration of Soybean Curd Whey for the Separation of Functional Components (유용성 물질의 분리를 위한 두부순물의 한외여과)

  • 서성희;황인경
    • Korean journal of food and cookery science
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    • v.13 no.4
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    • pp.507-513
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    • 1997
  • To separate and concentrate functional components contained in soybean curd whey, ultrafiltration was performed using regenerated cellulose or polysulphone membrane of spiral-wound type with MWCO 10,000, and the permeate and retentate solutions were analyzed. As the pH of soybean curd whey increased, the permeate flux decreased in both membranes. Treatment of 0.01 M EDTA rather decreased the permeate flux compared with control. The concentration of ionic calcium, which decreased with the pH increase, was thought to affect the permeate flux also. In case of polysulphone membrane, the permeate was efficiently purified and the retentate protein was concentrated significantly in which the membrane rejection value (MRV) for chemical oxygen demand (COD) was 79.25% and that of protein was 98.42% at the volume concentration ratio (VCR) of 10. MRV of the protein of regenerated cellulose membrane was lower than that of polysulphone membrane. To recover oligosaccharides to the permeate solution and increase the content of raffinose and stachyose, regenerated cellulose membrane was more suitable than polysulphone membrane and the optimum VCR was 4.

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Effect of Coagulants on the Quality of Soybean Curd Added With Cow's Milk (응고제가 우유 첨가 두부의 품질에 미치는 영향)

  • Kim, Tae-Young;Kim, Joong-Man;Cho, Nam-Jun
    • Applied Biological Chemistry
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    • v.37 no.5
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    • pp.370-378
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    • 1994
  • Soybean curd added with 40% of cow’s milk was prepared with eight coagulants such as calcium acetate, calcium lactate, calcium chloride, calcium sulfate, magnesium chloride, glucono-delta lactone (GDL), acetic acid and lactic acid. The curd products were evaluated by the chemical composition, coprecipitation porperties, mineral content, yield, color and textural characteristics. The lowest concentrations for protein coprepitation were 0.3% (v/v) for calcium salts, 0.4% (v/v) for magnesium chloride, 0.2% (v/v) for organic acids. Turbidity and crude protein of whey were markedly decreased at these concentrations. The optimal concentrations of coagualnts used for soybean curd preperation were 1.2% (v/v) for calcium acetate, calcium sulfate and calcium lactate, 1.0% (v/v) for calcium chloride and GDL, 0.8% (v/v) for magnesium chloride and lactic acid, 0.6% (v/v) for acetic acid. It was observed that of the eight coagulants tested, calcium chloride provided a satisfactory curd in quality. Calcium content of soybean curds by the calcium salt coagulants was higher than that by organic acid coagulants. Through the examination on the textural properties by a texturemeter was found out that acetic acid treated soybean curd among the organic acids, calcium salts and magnesium chloride treated curds had very high hardness value. All the curd products prepared in this experiment had a pale yellow color as affected by the value of L (lightness), a (redness) and b (yellowness). Although the colorimetric readings showed that the soybean curds prepared with the organic acids had higher L value but lower a and b value in comparison to calcium salts and magnesium chloride treated curds.

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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.