• The Korean Journal of Food And Nutrition
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• v.24 no.1
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• pp.12-16
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• 2011

This study was conducted to investigate the quality characteristics of soybean curd prepared with Opuntia ficus-indica fruit, freeze-dried Opuntia ficus-indica fruit powder, or heat-dried Opuntia ficus-indica fruit powder, without addition of a coagulant. The yield rates of the soybean curd were slightly decreased for the three curds containing Opuntia ficus-indica fruit; this was accompanied by a significant decrease in pH. Furthermore, the hardness and springiness of soybean curds coagulated with added freeze-dried Opuntia ficus-indica fruit powder or heat-dried Opuntia ficus-indica fruit powder were higher than the hardness and springiness of the coagulated controls. However, the cohesiveness and brittleness of two soybean curds were lower than for the controls, while the gumminess of the four soybean curds containing control fruit was the same. In terms of overall acceptability, the preferred soybean curd was the curd containing freeze-dried Opuntia ficus-indica fruit powder.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.381-386
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• 1985

This experiment was conducted to investigate changes of soybean curd yield according to the extension of soaking time during manufacturing of soybean curd. To investigate those changes systematically, transmission electron microscopy and disc-gel electrophoresis were used. The soybean curd yield was increased from 45.0% to 50.5% and 55.4% respectively as soaking time is extended from 5 hours to 10 and 24 hours. The solid extraction and soybean milk coagulation were also increased according to the extension of soaking time. From disc-gel electrophoresis patterns of soybean milk protein and soybean curd protein, numbers of band were increased and major band thickened by expending the soaking time. Most of high molecular bands of soybean milk protein were transfered to soybean curd. Crude 7S proteins of soybean milk and soybean curd in dis-gel electrophoresis were appeared to be 4 and 5 bands respectively, and crude 11S proteins of soybean milk and soybean curd were appeared to be 9 and 8 bands respectively. Of soybean milk bands, most of 11S component transfered to soybean curd. Transmission electron photomicrographs revealed that the dimension of each protein body became larger and the numbers of spherosome around the protein bodies in unit area fewer by extending the soaking time of soybean.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.363-368
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• 1990

As a work on the investigation of the processing aptitude of the Korean soybean cultivars, the soybean curd was made from 19 Korean soybean cultivars on a laboratory scale. The yield, proximate composition and rheological and organoleptic property of the resultant soygean curd were analyzed. The yields of soybean curd were ranged from 262.33% to 311.63%, being positively correlated with the soluble protein contents of the recommended soybean cultivars (r=0.9621). The recovery rate of protein in Baekun and Yeunha to the soybean curd was 72.94%, 70.62%, respectively. More than 80% of lipid in soybeans of Yeunha, Dankyung, Danyeob was transferred to the soybean curd. Lightness of the soybean curd made from Baekun, Kwanggyo, Saeal, Hill was higher than that of the others. The mechanical hardness of the soybean curd was strongly correlated with the final moisture content of the soybean curd (r =-0.8312), but not with the protein content of the soybean (r=0.1848). In the organoleptic test for color, texture, flavor and overall preference of the resultant soybean curd, the quality of Dankyung, Namcheon, S-138, Baekun was evaluated highly.

• 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.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.361-367
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• 1996

As a part of investigation for quality improvement of surimi gel from fish with a red muscle by addition of emulsion curd, we investigated the processing conditions of emulsion curd contained succinylated gelatin from conger eel skin as an emulsifier and emulsion curd-added surimi gel. Activity and stability of emulsion curd on standing at room temperature, chilled temperature and vibration were remarkably improved by the addition of 15 tunes of soybean oil and 5 times of water to succinylated gelatin from conger eel skin. The proximate composition of the emulsion curd was moisture 18%, protein 5%, lipid 76% and ash 0.5% and its appearance was white. Peroxide value and fatty acid composition of emulsion curd contained succinylated gelatin as an emulsifier were similar to these of soybean oil. By the addition of 6% of emulsion curd to mackerel surimi, gel strength, appearance and texture of the resulting surimi gel were improved, while its peroxide value and brown pigment revealed minor change. From the results of volatile basic nitrogen, viable cell counts and histamine content, the emulsion curd-added mackerel surimi gel can be safe In the sense of food sanitation.

• Journal of Life Science
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• v.21 no.2
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• pp.235-241
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• 2011

The purpose of this study was to isolate soy curd forming bacterial strains. Soy curd forming bacteria were isolated from Kimchi, a traditional Korean vegetable food that is fermented using lactic acid bacteria. Among 196 bacterial strains, ten isolates (strain No. 2-2-2, 2-15-2, 2-18-1, 2-19-2, 3-4-1, 3-4-2, 3-8-1, 3-8-3, 3-17-1, 4-39-5) formed firm soy curd. The isolated bacterial strains were identified by molecular biological and biochemical analyses. The genomic DNAs extracted from the isolated bacterial strains were used as a template for PCR amplification of 16S rDNA region. By comparing the results of the 16s rDNA sequences with GenBank data, the isolated strains were identified as Leuconostoc mesenteroides group and Lactobacillus sakei group. The phylogenetic position of soy curd forming strains and their related taxa were investigated using neighbor-joining method. L. mesenteroides group was further identified as L. mesenteroides subsp. dextranicum based on biochemical properties. L. sakei group was named Lactobacillus sp., because it showed a variety of biochemical properties.

• Journal of Life Science
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• v.12 no.3
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• pp.369-373
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• 2002

The waste-water from the industry for production of a soybean curd (the soybean curd waste-water) was investigated to use for the substrate to produce the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1 used as one of well known microbial pesticides. The pH of the soybean curd waste-water was 9.8 and its chemical oxygen demand (COD), total nitrogen (TN) and phosphate (TP) were 276.0, 71.1 and 5.5mg/$\ell$, respectively. The higher was the concentration of the soybean curd waste-water in the medium, the more endotoxin was produced. Maximal sporulation occurred at which concentration of $K_2$HPO$_4$in the medium supplied with the soybean curd waste-water was 1% (w/v). Production of the endotoxin with the optimized medium supplied with the soybean curd waste-water was 1.5 times higher than that without the soybean curd waste-water. The soybean curd waste-water was found to be suitable substrate for production of the endotoxin of Bacillus thuringiensis subsp. kurstaki HD-1.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.135-143
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• 2008

The ratio between 11S Sand 7S globulins was greater in large seed size varieties (LSSVs) of soybean than in small seed size varieties (SSSVs) or medium seed size varieties (MSSVs) but did not differ between MSSVs and SSSVs. The cysteine and methionine contents of 11S globulins were greater than those of total seed proteins and 7S globulins. The acidic monoamino monocarboxylic amino acids were the most abundant class of amino acid in soybean seed (27.2%) and soybean curd protein (29.3%). Isolated 7S and 11S fractions were analyzed by HPLC. Of the 12 peaks detected, 4 constituted 64.1% of the proteins of the SSSVs, 65.6% of the proteins of the MSSVs, and 70.5% of the proteins of the LSSVs. The 11S/7S globulin ratio was related to the yield and hardness of soybean curd. The MSSVs had the greatest yield of soybean curd, but the soybean curd hardness of the MSSVs was greater than that of the SSSVs. These results show that the 11S/7S ratio and color of soybean seeds can be used to predict the yield, hardness, and color of soybean curd.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.673-677
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• 1993

The effects of soybean products(bean curd and curd residue) on the cholesterol profiles of serum and liver were studied in rats. Male rats were fed on purified diets, supplemented with cholesterol, containing casein (CAS), dried bean curd(DBC), or mixture of casein and dried bean curd residue(CBCD, 3:1, w/w) as a protein source for 4weeks. Dietary DBC and CBCD, compared with CAS, reduced markedly the concentration of serum cholesterol. The concentration of HDL-cholesterol was significantly higher in the CAS group than in the CBCD group, but there were no significant differences in the ratio of HDL-cholesterol to total cholesterol. Liver cholesterol was lower in the DBC group than in the CAS and CBCD groups. The results suggest an effective cholesterol-lowering action of soybean products in rats fed on cholesterolemic diets, and further a possibility that than curd dreg decrease the concentration of serum cholesterol, regardless of the presence of animal protein in diets.

• Journal of Food Hygiene and Safety
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• v.18 no.4
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• pp.202-210
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• 2003

This study aims at making a HACCP(Hazard Analysis Critical Control Point)plan to be applied to soybean curd and verifing its effectiveness. First, we develped a general model of HACCP according to the guidelines of Codex (FAO/WHO). And we applied the model to 4 soybean curd workshops for 3 months. The HACCP model is composed of these procedures; HACCP team organization, production description, work flow chart, hazatd analysis, CCP (critical control point) decision, CL (critical limit) establishment, monitoring method decision, correction, verification and documentation. CCP were selection procedure and refrigeration procedure in non-wrapped soybean curd. CCP were selection procedure, heat-sterilizing and refrigeration in wrapped soybean curd. The result of bacterial experiment after apling the model for 3 months, the bacterial numbers of soybean curd box, wrapper, and soybean curd production were lower after appling than before appling, the model. We could verify that the appications of the HACCP model were effective to the soybean curd workshops.