• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1096-1101
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• 1997

Soy curd was prepared using imported soybean(U.S.grade A) and changes in quality were evaluated using different types and mixtures of coagulants(CaCl$_2$, CaSO$_4$, MgCl$_2$, MgSO$_4$, and glucono-$\delta$-lactone). Quality of soy curd was determined by rheological properties, yield, and color. Based upon the characteristics of each coagulant, mixtures of two coagulants were prepared in various ratios. The mixture of CaSO$_4$or MgCl$_2$with glucono-$\delta$-lactone(GDL), and that of CaSO$_4$or MgCl$_2$with MgSO$_4$resulted in soy curd of good quality in terms of rheological properties and yield.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.547-553
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• 2007

The physicochemical and functional properties of tofu prepared with kanghwang(Curcuma aromatica Salab.) were investigated, in order to study the effects of six different commercial coagulants. The coagulant concentrations were determined as 0.3% GDL, 0.3% $MgCl_2$, 1.0% $CaCl_2$, 1.5% $CaSO_4$, 0.45% mixed coagulant, and 1.5% Milky-Mg by pre-experiments. Also, the optimum concentration for the added kanghwang(Curcuma aromatica Salab.) was chosen as 0.01%. The yields of the kanghwang tofu prepared with Milky-Mg, mixed, and GDL coagulants were higher than those prepared with $MgCl_2$, $CaCl_2$, and $CaSO_4$. The pH of the kanghwang tofu prepared with the $MgCl_2$ coagulant was higher than when made with the other coagulants. The turbidity of the kanghwang tofu was highest when it was coagulated with GDL, and moisture content was highest or the of kanghwang tofu coagulated with $CaCl_2$. In the color analysis of the kanghwang tofu, the $L^{***}$ value was highest with the Milky-Mg coagulant, while the $a^{***}$ value was highest and the b value lowest with the GDL coagulant. For the textural properties, the hardness results were in the order of $CaSO_4$ > $CaCl_2$ > $MgCl_2$ > mixed > GDL > Milky-Mg, springiness, gumminess, and brittleness were highest in the tofu coagulated with Milky-Mg. For the overall acceptability of the sensory properties, the Kanghwang tofu that was made using the mixed coagulant had the highest score.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.769-775
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• 2010

Quality characteristics and antioxidant activity of spirulina with added tofu were investigated in the presence of different coagulants ($CaSO_4$, $MgCl_2$, Glucono delta lactone (GDL), vinegar). The yield of the spirulina tofu was the highest when coagulated with GDL. The pH of spirulina tofu with $MgCl_2$ was the highest compared to those of other coagulants. The tumidity of spirulina tofu was the highest with $MgCl_2$. In the color analysis of spirulina tofu, the L (lightness) value was the highest with $CaSO_4$, whereas a (redness) value was the highest with $MgCl_2$. C-phycocyanin contents were the highest with the $CaSO_4$. Phycoerythrin of spirulina tofu for vinegar was 0.194 mg/mL, and GDL content was 0.214 mg/mL. Additionally, the antioxidant activity of spirulina tofu was the highest with $MgCl_2$ $IC_{50}$ values of the DPPH radical scavenging activity of spirulina tofu with $MgCl_2$ was 89.2 mg/g, GDL 93.5 mg/mL, $CaSO_4$ 116.7 mg/mL, and vinegar 118.0 mg/mL. The texture analyses (TPA) results showed that hardness was in the order of vinegar>$MgCl_2$>GDL>$CaSO_4$. For the overall acceptability of the preference test, the spirulina tofu that was made using $MgCl_2$ coagulant had the highest score. Based on these results, it is suggested that $MgCl_2$ is the proper coagulant for the preparation of spirulina with added tofu.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.161-166
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• 1999

CaCl2 and water soluble degraded chitosan mixtures were used as coagulants for extending the shelf life of tofu. Microbial counts, pH, and turbidity in tofu immersion solution were analyzed during the periods of storage at 4oC and physico chemical properties of tofu were determined by rheological properties, color and yield. There was no significant difference in moisture content and yield between tofu made with and without chitosan. Failure stress and stress relaxation values were reduced when chitosan was added to CaCl2, but there was no significant change among contents of chitosan added to tofu. The pH values were decreased at the beginning and then slowly increased after 14 days storage. The changes in turbidity were increased during storage, but the change in 2.0g degraded chitosan mixture with 7.0g CaCl2 coagulant(2.0:7.0 ratio) was lower than others and initial turbidity was lower as much as chitosan added to coagulant. These data showed that the water soluble degraded chitosan had a good anti microbial effect and increases the shelf life of tofu.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.402-409
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• 2000

To investigate the textural and physical characteristics of WSF(whole soybean flour) tofu affected by coagulant and its concentration, $CaCl_2$, $CaSO_4$, $GDL(glucono-{\delta}\;lactone)$, $MgCl_2$, and some mixed coagulants were used in this study. Yields of WSF tofu coagulated with $CaSO_4$ and GDL were ranged 4.3-4.5(g/g WSF), but common tofu was 2.2-3.0(g/g soybean). As the water addition ratio increased, L and a value were increased while heating time increased, b value increased. L value of WSF tofu was lower and b value was higher than conventional tofu and 4 commercial tofus. Kinds of coagulant and its concentration significantly affected to textural properties of WSF tofu. As the concentration of coagulant increase, the hardness increased in most all coagulants. WSF tofu coagulated with $CaSO_4$ and GDL recorded low hardness and adhesiveness, and high springiness among the used coagulants at the same concentration. As the hardness increased, the gumminess and chewiness increased in most all coagulants. As coagulation temperature and molding pressure increase, hardness also increased. WSF tofu coagulated with 0.3% $CaSO_4+GDL$ was the most similar in the textural properties with conventional tofu and 4 commercial tofus. WSF tofu coagulated with 0.3% of $CaSO_4+GDL$ at $85^{\circ}C$, 10 times water addition, 5min. heating and $25.0g/cm^2$ molding pressure recorded the highest score in the sensory evaluation.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.56-61
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• 1985

The mass balances of calcium salts during the manufacturing processes of Tofu were established by conductometric method and chemical analysis method. During the manufacturing processes of soy milk and Tofu, 66% of solid and 63% of calcium was transfered from soy-bean to the soy milk, and 47.8% of total solid from soybean was transfered to the Tofu, respectively. When the $CaCl_2$ was used as coagulant, calcium contents in Tofu $(Y_{Tofu},\;mg{\cdot}Ca/g{\cdot}Tofu,\;wet\;basis)$ and drained solution $(Y_{drained\;soln},\;mg{\cdot}Ca/ml{\cdot}drained\;soln.)$ were linearly increased with the amounts of $CaCl_2(C,g{\cdot}CaCl_2/ml{\cdot}soy\;milk)$ added in soy milk, and correlative equations between them were obtained as $Y_{Tofu}=0.3369\;C+1.2689$ for Tofu$(moisture\;content:\;81.5{\pm}0.5%)$ with r=0.9898, and $Y_{drained\;soln}= 0.2899C+0.0399$ for drained solution with r= 0.9991. It was proved that conductometric method was reasonably applicable to the measurement of calcium contents of the products from every processes of Tofu manufacture except soy-bean. However the conductometric method was not recomendable in the case of $CaSO_4$ as coagulant due to its low solubility ana uneven distribution in soy milk and Tofu tissue.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.286-292
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• 2009

This is the basic study of Cheong-song mineral waters(Dalgi and Sinchon) for a coagulant of Tofu. For comparison, $CaCl_2,\;CaSO_4,\;MgCl_2\;and\;MgSO_4$ are used as reference coagulants. The coagulability test was conducted by measuring the percentage transmittancy of filtered whey solution at 600 nm wavelength, in $80\;{^{\circ}C}$ and 10 mL of solution volume which composed of 2 mL of soy milk and coagulants. The coagulability test of mineral waters require more than an aliquot of 8 mL. Good result obtained by adding 0.4, 1, 0.8, 0.8 mL of reference coagulants and this is equivalent to the amount of 66.14, 232.83, 95.68, 78.88 mg of Ca and Mg respectively. The percentage transmittancy of filtered whey solution with added 8 mL of Dalgi and Sinchon mineral waters showed 50.74 and 58.52 respectively and the amount of mineral content of Ca and Mg equivalent to 2.41 and 2.48 mg respectively which is very lower value than the reference coagulants. This means mineral water has coagulation ability even in the low concentration.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.617-622
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• 2001

Changes of quality properties of fermented tofu prepared with two molds like Actinomucor elegans (AE) and Rhizopus oligosporus (RO) and coagulants (CaCl$_2$ and citric acid) were investigated. Moisture and crude protein of fermented tofu were rapidly decreased during fermentation, the contents of crude lipid and crude ash were shown to be slightly increased, ad then total acidity was slowly decreased. The content of reducing sugar of fermented tofu was slowly increased for 7 day of fermentation, but rapidly increased after that time because of rapid hydrolysis of carbohydrate in fermented tofu. The contents of amino and ammonia type nitrogen were quickly increased during fermentation. The highest contents of amino type nitrogen of fermented tofu were found in sample of CaCl$_2$group as a coagulant and RO group as a mold. Contents of minerals in tofu fermented for 14 day were high in order of K>Ca>Mg>Na. Iin conclusion, AE was more effective than RO to enhance the contents of reducing sugar and amino type nitrogen as an indicator of fermentation within 7 day of fermentation, and then RO was more effective than AE after that time. Calcium chloride as a coagulant was more effective than citric acid in tofu fermented with the same strain for 14 day.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.25-31
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• 1988

The crude calcium acetate (CCA) was made from egg-shell and acetic acid to use the CCA as a coagulant for Tofu (soy bean curd). Amount of CCA. $CO_2$ and residue made from 5.6g egg-shell (average weight of a egg-shell) and 10% acetic acid(50m1) was 3.8g, $300{\pm}10ml(at\;25^{\circ}$ and 2.1g. respectively. Tofu formable minimum concentration of the CCA was about 0.14% similar to that of $CaCl_2$, $MgCl_2$. Volume, hardness, taste and content f protein and lipid of Tofu by addition of CCA were not significantly different in those of Tofu that magnesium chloride and calcium chloride were used.