• Korean journal of food and cookery science
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• v.26 no.4
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• pp.406-412
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• 2010

This study was conducted to investigate the effects of saltwort on the quality characteristics of tofu. In addition, we examined the potential for commercialization of tofu containing saltwort. For this study, saltwort was added to tofu at 0%, 4%, 8%, 12%, 16% and 20% and quality and sensory tests were administered. Analyzing the mineral contents of saltwort juice, K was present in the greatest amount, followed by Mg, P, Ca, and F (in decreasing order). There were significant differences in yield rates and turbidity between the groups. Acidity was highest in the control group, and acidity and volume of tofu tended to decrease with an increase in saltwort powder. L value and a value decreased as the content of slaltwort powder increased, but b value increased with increasing saltwort powder concentration. Hardness, chewiness, and gumminess were rated higher in the control and the 4% supplement groups than the others groups. In the sensory evaluation, cross section and soybean flavor were the highest in the 4% saltwort supplement group, and the presence of an "off-flavor" increased with the content of saltwort powder. The saltiness score was highest in the 20% supplement group. The 4% and 8% supplement groups were favored in the "feel after swallowing" assessment. Softness was the lowest in the 20% supplement group, and the 4% supplement group had the highest overall acceptability. As demonstrated by these results, the addition of saltwort positively affected the overall sensory evaluation of tofu and supplementation with saltwort at 4% and 8% might be considered the most appropriate choices. In conclusion, saltwort tofu expected to increase the functionality of new products, particularly with respect to product variety and health improvement.

• Food Science and Preservation
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• v.21 no.2
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• pp.215-223
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• 2014

The quality characteristics and antioxidant activity of three kinds of tofu made from lipoxygenase (LOX)-free genotypes soybeans were compared to the Taekwang (LOX-present) tofu as the control. The mineral contents of Jinyang tofu were significantly higher than those of the control. The hardness and gumminess of tofu made from LOX-free genotypes were significantly higher than those of the control. Gaechuck#2 tofu showed higher sensory evaluation results than the other kinds of tofu in terms of taste, flavor and overall acceptability. The total isoflavone contents were higher in the LOX-free genotypes than in the control. The total phenol content was similar for the Gaechuck#1, #2 and Taekwang tofu. The flavonoid content was higher in Gaechuck#1 and #2 tofu than in the control. The antioxidant activities were the highest in Gaechuck#1 tofu, followed by the Gaechuck#2. During the 15-day storage at $4^{\circ}C$, the turbidity of the immersing water tended to increase, but Gaechuck#1 and #2 tofu were significantly lower than in the control after 15-day storage. Therefore it is suggested that Gaechuck#2 tofu could be the suitable genotype for tofu products because it is the most effective in terms of overall acceptability, antioxidant activity, and storage stability.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.92-98
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• 2021

The effects of heat-moisture treatment (HMT) on rice flour (RF) have been investigated for possibility of texture modifier in protein-based foods matrix, tofu. The optimum condition for preparation of tofu with maximum textural parameters was investigated by using response surface methodology (RSM). Rice flour was subjected to moisture content (10-30%) and heating temperature (100-140℃). Based on the response surface and superimposed plots, the optimized conditions of hydrothermally treated rice flour was as followed: moisture content, 22%; temperature, 130℃, which showed lower swelling power as compared to native RF and became more stable during continuous heating and agitation than native one. Tofu, prepared with HMT-RF, showed a denser network structure than that with RF, thereby inducing an increase in textural parameters. From the above results, the addition of HMT-RF could preserve the quality of tofu and be useful for developing an acceptable protein-based food product.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1307-1311
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• 2008

This study was conducted to evaluate the quality characteristics of mugwort-tofu prepared by purified salt (A1), sun-dried salt (A2), bamboo salt (A3), and deep ground water salt (A4) in addition to $CaCl_2$ as coagulants. Addition of various salts with $CaCl_2$ increased yield of the tofu resulting in high content of lipid, protein and mineral contents of mugwort-tofu. Sun-dried salt was most effective in yield of the tofu among tested salts. It was also most efficient in increasing protein, and lipid contents of the tofu. The amounts of Ca, K, Mg, and Na were highest in mugwort-tofu prepared with sun-dried salt, while they were lowest in the tofu with deep ground water salt. The texture analysis showed the tofu prepared with various salts generally increased the hardness and gumminess of the tofu significantly. The sensory evaluation of the tofu with various salts demonstrated that the saltiness, tastiness, chewiness, and overall acceptance were enhanced significantly. Among tested salts, bamboo salt showed the highest overall acceptance in mugwort-tofu, followed by deep ground water salt, purified salt, and sun-dried salt.

• Korean journal of food and cookery science
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• v.24 no.5
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• pp.691-698
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• 2008

In this study, we assessed the quality characteristics of soybean curds (tofu) prepared with Mesangi (Capsosiphon fulvescens) powder (0, 2, 4, 6%, w/w) were investigated. The yields of the curds containing Mesangi were higher than those of the control, and the yield increased with increasing quantities of Mesangi powder. The most abundant mineral in Mesangi tofu was calcium, followed by magnesium. The Mesangi tofu had a slightly lower pH than the control. The addition of Mesangi powder to curd evidenced a significantly lower L value (lightness) and a value (redness) than was detected in the control (p<0.05). The hardness level was highest in the tofu to which 2% Mesangi powder was added. However, this level decreased with increasing concentrations of Mesangi powder. Although the 4% Mesangi tofu evidenced higher adhesiveness than was detected in the control, we noted no significant differences among the Mesangi-treated curds. The soybean curds added to which 2% Mesangi powder was added had evidenced the highest level of cohesiveness, but the tofu containing 4 and 6% Mesangi powder was significantly reduced as compared with the control and 2% Mesangi tofu. Springiness, gumminess, and brittleness were higher in the 2% Mesangi tofu than in the others (p<0.05). The soybean curds prepared with Mesangi powder evidenced a lower total plate count than the controls during over 12 days of storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.833-839
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• 1998

Hwangkeum Kong was stored at 5$^{\circ}C$, $25^{\circ}C$ and 35$^{\circ}C$ for 8 months to investigate the changes of the suitability for Tofu processing. The properties of Tofu prepared with the soybeans stored at 5$^{\circ}C$ for 8 months showed no significant differences from the non-stored control soybeans. However, soybeans stored under high temperatures showed low yield, water holding capacity and Sag value of Tofu Compared with the soybeans stored at 5$^{\circ}C$ for 8 months, fracturability in the texture of Tofu significantly increased when the soybeans had been stored at $25^{\circ}C$ and 35$^{\circ}C$ for 8 months, while hardness, cohesiveness, adhesiveness, elasticity, gumminess and chewiness decreased. The color of Tofu changed from pale yellow to brown depending on high temperature and long-term of storage. The Tofu prepared with the soybeans stored under high temperatures was significantly different in sensory evaluations from the non-stored soybeans as well as from the soybeans stored at 5$^{\circ}C$ for 8 months in color(p<0.01), texture(p<0.05) and taste(p<0.05).

• The Korean Journal of Food And Nutrition
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• v.33 no.6
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• pp.710-720
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• 2020

This study was conducted to compare the quality characteristics of firm tofu (coagulant calcium chloride, CaCl2 used) made from eight imported and four domestic soybeans selling in Korean markets. The 100-seed weight of soybeans imported from China and Seonpung cultivated in Korea was the highest at 33.23 g and 32.51 g, respectively. Soybeans imported from the USA (bulk type) showed the lowest at 16.12 g, followed by Ukraine at 16.94 g, and Brazil at 18.51 g. The range of protein and fat in the 12 soybeans was 37.08~41.36% and 18.35~22.17%, respectively. The isoflavone contents were the highest in Daepung2 cultivated in Korea at 3,764.10 ㎍/g and the lowest in soybeans imported from Brazil at 1,439.85 ㎍/g. Tofu yield among the samples was in the following order: Seonpung (235.2%), China (232.0%) Daepung2 (228.7%), Daechan (225.7%), and Brazil (208%). Tofu made with soybeans cultivated in Korea (including from China) showed a higher yield compared to that made from soybeans from seven other countries. In the analysis of the correlation of quality factors of tofu, the hardness of the tofu was correlated with 100-seed weight (r=0.676⁎) and protein content of the soybeans (r=0.837⁎⁎). Tofu yield was correlated with 100-seed weight (r=0.748⁎⁎) and protein content of the soybeans (r=0.583⁎).

• Food Science and Preservation
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• v.21 no.5
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• pp.688-693
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• 2014

The quality and sensory characteristics of tofu were investigated with various levels of black garlic extract (BE) added to it in 0, 1, 3, 5 and 7%-weight soymilk, before it was coagulated with $MgCl_2$ (MC, BEM-A, BEM-B, BEM-C and BEM-D) and concentrated to $8^{\circ}Brix$ deep ground sea-like water (SC, BES-A, BES-B, BES-C and BES-D). The overall acceptability of the tofu samples was higher (SC > BES-A > BEM-A) than that of the other samples. The addition of BE was influenced by the color, flavor and taste of the tofu, and the more BE was added, the tougher the tofu became. The tofu yield with various amounts of black garlic extract did not significantly differ among the samples. The pH range was 5.61~6.15 and decreased as more BE was added, whereas the turbidity increased. Also, the L value of the tofu decreased as more BE was added. The a value showed a tendency opposite that of the L value. The b value did not significantly differ among the samples. The texture profile analysis of the tofus showed that the hardness, chewiness, and gumminess significantly increased as more BE was added. In conclusion, it was found that the addition of 1% BE will improve the quality and sensory characteristics of tofu.

• Journal of the Korean Society of Food Culture
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• v.24 no.3
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• pp.315-320
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• 2009

This study was conducted to investigate the quality characteristics of tofu prepared with different concentrations of lotus leaf powder. The determined values for moisture, crude ash, carbohydrate, crude protein, and crude lipid in were 2.97%, 8.09%, 65.18%, 22.83%, and 0.93%, respectively. The yield rates of the tofu samples did not differ significantly according to the level of added lotus leaf powder; however, there was a significant decrease in pH and a significant increase in acidity. The L- and a-values of samples decreased as the amount of lotus leaf powder in the formulation increased, whereas the b value increased. Furthermore, hardness significantly increased as the level of lotus leaf powder increased. In terms of overall acceptability, the preferred tofu samples were the control and that containing 0.2% lotus leaf powder.

• Food Engineering Progress
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• v.13 no.2
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• pp.99-104
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• 2009

Tofu has been playing an important role in people's daily diet in most of Asia and recently in North America due to several health-promoting functions, preventing and treating a number of chronic diseases such as cancer, coronary heart disease and osteoporosis. The objective of this study was to investigate the effect of different levels of yakong incorporation (0, 5, 10, and 15%, w/w) in preparation of firm tofu. Quality parameters such as pH, titratable, moisture content, color, and consumer preference were determined, and their correlations were analysed. There were no significant differences in pH, titratable acidity, and moisture content due to different levels of yakong incorporation studied (p>0.05). A significant decrease in L$^{*}$ and b$^{*}$-values whereas significant increase in a$^{*}$-value was observed (p<0.05). Five percent yakong tofu received the most favorable mean scores with respect to color, texture, and overall acceptability. Correlation analysis revealed that yakong incorporation was well correlated with some of physicochemical properties as well as consumer preference.