• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.77-83
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• 2008

This study investigated the quality of tofu prepared by treating soybean milk with deep seawater as a coagulant. The quality and shelf-life of the tofu prepared using the deep seawater coagulant were determined and compared to those using $CaSO_4$, surface seawater, and intermediate seawater coagulant. The tofu made with the deep seawater coagulant was firmest. In addition, the deep seawater tofu product had more, smaller particles in the microscopic view, compared to the tofu made from surface and intermediate seawater coagulants. The deep seawater tofu product had the lowest viable cell counts and turbidity. In addition, the deep seawater tofu product had a longer extended shelf-life. From these results, deep seawater appears to improve the texture, taste, and shelf-life of tofu when used as a coagulant.

• 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 Fisheries and Aquatic Sciences
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• v.40 no.3
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• pp.113-116
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• 2007

We investigated the characteristics of various Tofu coagulants extracted from sea tangle using treated deep ocean water (DOW) as the solvents. The coagulants were typical solutions extracted from sea tangle using raw DOW and strongly electrolyzed acidic (SAC) or alkaline (SAK) water. The total dissolved solids (TDS), NaCl and electric conductivity were increased in the coagulant solution extracted by SAC than the others. In the coagulant solutions extracted by acidic electrolyzed solvent, aspartic acid content (13.5 mg/100 g) was higher than others (11.2 and 12.1 mg/100 g). The Tofu obtained using coagulants extracted with treated DOW had the water contents ranging from 79.55% to 80.04%. The contents of crude protein (12.1 g/100 g) and Na, Ca, K and Mg were relatively higher than general Tofu commercially available. Therefore, coagulant solutions extracted from sea tangle using treated DOW can be used to develop natural high-grade tofu for practical use.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.441-446
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• 2017

Among the many foods, it is hard to find perfect food with nutrition and functionality like beans. Korean food culture is the main ingredient of korean culture, kochujang, soybean paste, and soy sauce, and processed soybean tofu is the main ingredient. Soybean meets high quality protein and fat, and it has excellent results in prevention and treatment of all kinds of diseases. Soybean food is becoming a new generation health food. In countries where animal protein intake is low, soybean is used as a protein source instead of animal protein. Tofu, a processed food, is a complete food with high digestibility. In order to publicize the superiority of soybean nutritional value, Tofu processing and powder were investigated by observing the size, shape and characteristics of bean powder using domestic soybeans and imported soybean, and the variation of the amount of coagulant.

• 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.

• Food Science and Preservation
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• v.20 no.5
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• pp.636-642
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• 2013

Quality and sensory characteristics of tofu prepared with concentrated to 8 $^{\circ}Brix$ deep ground sea-like water (SW) were investigated to check the availability for coagulants. The tofu was coagulated with three kinds of commercially coagulant, such as $MgCl_2$, $CaSO_4$ and glucono-${\delta}$-lactone. Different amounts of SW and soybean milk were added: SW-20 g/L, SW-25 g/L and SW-30 g/L. The moisture content and pH were significantly lower in which preparation with glucono-${\delta}$-lactone coagulated tofu, and others has not significantly difference each other. The mineral contents in the coagulant influenced the mineral content of the tofu, which contained larger quantities of major minerals. However, the mineral content of the tofu was not affected of the mineral concentration in the coagulant. The L and b values of the tofu prepared with SW were not significantly different. The hardness of the tofu prepared with the commercial coagulants was significantly lower than that of the tofu produced with the SW. The sensory property was lower when the hardness was lower and higher. In conclusion, the quality characteristics of SW-prepared tofu were not significantly different from those of the tofu prepared with the commercial coagulants, but the texture and the taste of the SW-prepared tofu were excellent.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.576-583
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• 2020

The purpose of this study was to compare the quality characteristics of silken tofu products from the commercial market in Korea. Seven types of commercial silken tofu were sampled and their physicochemical properties, including soluble solid contents, salinity, pH, total acidity, moisture contents (total solid contents), crude protein and fat contents were evaluated. The TPA results suggest that the texture of silken tofu was very different from one another according to the type of and the amount of coagulant. The commercial silken tofu showed a range of pH 5.53~6.48, total acidity of 0.12~0.32%, soluble solid contents of 2.62~5.07 °Brix, salinity of 2.28~4.30%, and moisture contents of 87.10~92.24%, respectively. In terms of the coagulant of tofu, besides the GDL (glucono-δ- lactone), other coagulants such as MgCl₂ for making 'silken tofu' in the Korean tofu market. The quality characteristics differed depending on the constituents of sample and the coagulants of tofu used. These results are expected to be useful in identifying new trends in the domestic silken tofu industry.

• 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.

• Korean Journal of Food Science and Technology
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• v.43 no.3
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• pp.329-333
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• 2011

Quality characteristics of tofu as affected by addition time (before or after coagulant) and the amount (0, 3, 6, and 9%) of astringent persimmon fruit (Diospyros kaki T. cv. Cheongdobansi) powder added were investigated. Yield and sensory acceptability were higher in tofu prepared by adding persimmon before than after adding the coagulant. The yield of tofu with added persimmon was higher than that of the control. The L value of the tofu decreased as the amount of added persimmon increased. Hardness, chewiness, and crispness of tofu made with 6% persimmon were higher than those of the others. DPPH radical scavenging activity tended to increase as persimmon concentration increased but no significant difference was observed between the 3% and 6% added persimmon treatments. A sensory evaluation showed no significant differences in aroma, beany, astringency, and texture. However, the 9% sample had the significantly lowest score for overall acceptability. Thus, astringent persimmon powder (3-6%, before coagulant addition) can be utilized as an additive during tofu processing.

• Food Science and Industry
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• v.54 no.3
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• pp.171-183
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• 2021

Tofu has been consumed as source of protein in Asia for hundreds of years and it was first known in US and Europe by Asian immigrants during 1900s. Lately it is being spotlighted for excellent plant-based protein that has nutritional value. Tofu has long been the most widely used ingredients in Asia and it has been developed into various forms such as tofu, yuba, fried tofu, tofu sheet, fermented tofu and more according to food culture. With development of equipment, coagulant, packaging and pasteurization, now we can have advanced flavor, productivity and distribution of tofu. Tofu has been brought to customer's attention, people who prefer more health oriented, sustainable and eco-friendly food during COVID-19 pandemic season. Furthermore, this global trend is expected to be continued. In response to the trend we need more study on new texture of tofu, substitution of meat, dairy, and various commercialization of HMR in future.