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

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.3
• /
• pp.455-459
• /
• 2001

Tofu (soybean curd) was made with whole soybean flour (WSF, 420 mesh) by various processing conditions of water addition ratio, heating time, coagulation temperature, molding pressure and 0.3% of mixed coagulant (CaSO₄:GDL=50:50(w/w)). Yield content of WSF-tofu was the highest in processing condition of 85℃ coagulation temperature, 10 times water addition, 5min. heating time and 25.00 g/㎠ molding pressure. As the increase of the water addition ratio from 8 to 14 times (water:WSF, v/w), Hunter's L and a values were increased. Raising of heating time (100℃, 1, 5, 10 and 15 min), a and b value were increased. Textural properties of WSF-tofu were significantly affected by coagulation temperature (75, 80, 85 and 90℃). Hardness was increased, but adhesiveness and cohesiveness were decreased. heating time was influenced on harness of WSF-tofu, but water addition ratio was not affected on hardness of WSF-tofu. Increasing of molding pressure (16.83, 25.00, 33.22 and 41.67 g/㎠, 1 hr) was resulted from a increased hardness, gumminess and chewingss of tofu, but adhesiveness was addition ratio, 5 min heating time and 25.00 g/㎠ molding pressure recorded the highest score in sensory evaluation test.

• The Korean Journal of Food And Nutrition
• /
• v.35 no.6
• /
• pp.521-530
• /
• 2022

This study was conducted to compare the quality characteristics of commercial tofu products from the market in Korea. Seventeen types of commercial tofu samples were taken and their physicochemical properties, including soluble solid contents, salinity, pH, total acidity and moisture (total solid contents), were analyzed. The hardness of tofu was negatively correlated with the moisture contents of tofu (r=-0.667^**). The commercial tofu showed pH 5.80~6.24, total acidity of 0.016~0.034%, soluble solids of 1.50~3.45°Brix, salinity of 1.20~2.30%, and moisture content of 79.91~87.57%, respectively. All 17 tofu samples sold in the Korean market were prepared using crude MgCl₂ and sea water as a coagulant. The quality characteristics vary depending on the constituent's of soybeans, and the ratio and amount of coagulants of tofu used. The origin of soybean seeds affected the yellowness of tofu; tofu made from imported soybean showed a higher b value than domestic soybean. These results are expected to be useful for understanding trends in the domestic tofu industry.

• Journal of the Korean Society of Food Culture
• /
• v.22 no.6
• /
• pp.696-704
• /
• 2007

To investigate of the perception and using behavior by age of tofu, 46.3% of male and 53.7% of female about 700 adults in Daegu and kyungbuk area were surveyed. 96.4% of the participants usually preferred the tofu owing to health and 68.4% of them had purchased tofu made of domestic soybean. In addition, the responses to 7 questions about the tofu were also measured on 5 point Likert scale. The item "Tofu is healthy food" was totally received the high point but "Tofu prevents osteoporosis" earned the lowest. Most participants relatively knew and had eaten common tofu, soft bean curd, uncurdled bean curd, fried bean curd against functional tofu such as tofu added with omija, surimi, spinach, etc. But they intended to eat functional tofu such as tofu added with green tea, black sesame, spinach, omija. Furthermore, 60.7% replied "increasing" prospects for the tofu consumption. 40.0% of adults said the plan should be "Make of good quality domestic soybean" for the purpose of better improvement to consume.

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

• Culinary science and hospitality research
• /
• v.20 no.6
• /
• pp.28-40
• /
• 2014

This study was conducted to investigate the effect of Tofu powder on the quality properties of hamburger patties. Thus, this study analyzed the physicochemical and sensory characteristics of hamburger patties containing Tofu powder(25%, 50%, 75%, 100%) instead of bread crumb. The result was as followed. Increasing the amount of Tofu powder in hamburger patties tended to increase the pH. Moisture content of control was higher than other hamburger patties when containing Tofu powder. Increasing the amount of Tofu powder in hamburger patties tended to decrease the moisture content. There were no significant differences in cooking loss rate regarding the weight. The addition of Tofu powder decreased the cooking loss rate of the diameters and increased the thickness. It also increased the lightness (L), the redness (a), and the yellowness (b) in the hunter color value of the hamburger patties. For the textural characteristics, the addition of Tofu powder increased the hardness, elasticity and gumminess of the hamburger patties; however, it decreased the brittleness. In the sensory evaluation, an addition of 100% Tofu powder had the best score in appearance, taste and the overall preference. Therefore, this result suggests that adding Tofu powder amount of 100% can be applied to the hamburger patties for preference and nutritional aspects purposes. Furthermore, it is believed that the development of healthy patty-type Tofu powder products may resolve worries about fast food and quality-related problems in hamburger patties.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.7
• /
• pp.999-1005
• /
• 2011

This study was conducted to investigate the quality characteristics of tofu (soybean curd) prepared with added Cheongyang hot pepper juice (CPJ). The moisture, crude protein, crude lipid, and crude ash contents of the control tofu were 82.98%, 10.26%, 4.86%, and 0.41%, respectively. The moisture content of tofu decreased according to the level of added CPJ, whereas the crude protein, crude lipid, and crude ash contents increased. The yield of tofu prepared with 5% CPJ significantly increased relative to that of control tofu. The turbidity and acidity increased with increasing concentration of CPJ, whereas pH decreased. The Hunter's color values of the tofu were significantly lower in L and a values and significantly higher in b values with increasing concentration of CPJ. The hardness, adhesiveness, and springiness of the tofu samples did not differ significantly according to the level of added CPJ. Capsaicin, dihydrocapsaicin, total polyphenol contents, and antioxidant (DPPH radical and ABTS radical scavenging activity) activities were significantly increased with increasing concentration of CPJ. Sensory evaluation indicated that the tofu prepared with 5% CPJ was not significantly different from the control tofu. Overall, CPJ could be used as an effective ingredient to improve the sensory and antioxidant properties of tofu without affecting the quality properties.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.4
• /
• pp.529-535
• /
• 1996

This study was performed to investigate some quality characteristics of 새려 prepared from soybean milk and various seaweed(Undaria pinnatifida, Laminaria japonica, Porpyra tenera, Enteromorpha sp., Codium sp.) pulps in the ration of 9:1(v:v) with 20% MgCl2. The yields of tofu containing Undaria pinnatifida, Laminaria japonica, or Enteromorpha sp. increased but porphyra tenera, Codium sp. decreased in comparison with tofu prepared from whole soybean milk. The protein content of tofu containing Undaria pinnatifida, Laminaria japonica, Porphyra tenera, or Codium sp. increased but Enteromprpha sp. decreased in comparison with the tofu prepared from whole soybean milk. The content of Ca in Undaria pinnatifida, Porphyra tenera added tofu was higher than that of the tofu prepared from whole soybean milk or other seaweeds added tofu. In sensory evaluation the texture, color, taste of tofu were favored with the addition of sea mustard(Undaria pinnatifida) pulp than that of the tofu prepared from whole soybean milk or tofu prepared other seaweed. Tofu prepared was possible with adding 0.5~1.5% sea mustard to soybean milk but the feasible added amount level was 1% of sea mustard. The yields, protein Ca, and K content of tofu were increased by the more adding amount of sea mustard tan tat of the tofu prepared from whole soybean milk. The hardness values of 1% sea mustard added tofu were decreased than that of the tofu prepared from whole soybean milk ; on the other hand, elasticity, cohensiveness, gumminess and brittleness of tofu with sea mustard increased. The L and a values of tofu were lower and b values were higher with the addition of 1% sea mustard. The content of histidine, tyrosine, leusine, and phenylalanine were decreased but the other amino acid were increased in tofu prepared from 1% sea mustard pulp added to soybean milk. The saturated fatty acid and monoene fatty acid content of tofu were increased and C18:2, C18:3(${\gamma}$), C18:3, C20:5 of polyene fatty acid were slightly decreased in tofu prepared from 1% sea mustard pulp added to soybean milk.

• Food Science and Preservation
• /
• v.23 no.6
• /
• pp.832-838
• /
• 2016

The purpose of this study was to investigate the effect of a fresh chlorella powder on yield, quality and self-life of organic soybean tofu. After added with a fresh chlorella powder, yields, physical properties, color, shelf-life and sensory properties of the organic soybean tofu added with chlorella powder was compared to the properties of soybean tofu. The yield of soybean tofu increased with the addition of more than 1% chlorella powder. Hardness of the organic soybean tofu with chlorella significantly increased compared to that of the soybean tofu. However, Hunter's color values of L, a, and b decreased by increases in the chlorella powder concentration. Total microbial population of the soybean tofu was higher than that of the organic soybean tofu with chlorella. However, pH of chlorella tofu decreased during storage period at $4^{\circ}C$. After 7 days storage at $4^{\circ}C$, the total microbial population decreased significantly with the addition of 2% chlorella powder. The L and a value of chlorella tofu was increased. On the other hand, the b value of chlorella tofu was decreased during storage. The results revealed that a fresh chlorella powder was a useful material to improve yield, quality and storage condition of the organic soybean tofu.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.2
• /
• pp.412-419
• /
• 2004

To investigate the utilization of calcium lactates (CaL) as coagulants for tofu manufacture, the quality characteristics and shelf-life of tofu made by CaL-P (black snail powder) and CaL-A (black snail ash) were investigated and compared to calcium chloride (CC), magnesium chloride (MC), calcium sulfate (CS ) and standard calcium lactate (CaL-S). And also, total microbe and turbidity of the tofu were determined during storage at 1$0^{\circ}C$. Coagulation ability of CaL-A was the highest, and the ability of CaL-P was higher than that of CaL-S. Yield of CaL-A tofu was similar to those of CS and CC tofu, while the yield of CaL-P tofu was 50% compared to that of CC. L＊ value of CaL-P tofu was lower, but a＊ and b＊ values were higher than those of other tofus. The hardness of tofu showed in the order of CaL-S>CS>CC>CaL-P>MC>CaL-A, while the cohesiveness showed in the order of MC>CaL-S>CC>CS>CaL-P>CaL-A. Calcium contents were 57 mg% in MC tofu, 174 mg% in CS tofu, 116 mg% in CaL-S tofu, 95 mg% in CaL-A tofu and 172 mg% in CaL-P tofu. From the results of microscopic observations, the lower hardness showed the more soft and the smaller particle. The particle of CaL-A tofu was small and uniformity but the size of CaL-P and CC tofu showed coarse. Sensory quality of CaL-P and -A tofu were better than the other tofu evaluated by texture, springiness, flavor and overall taste. The shelf-life estimated by total microbe was 4∼6 days in CC, MC, CS, CaL-S and CaL-A tofu, but 8 days in CaL-P tofu at 1$0^{\circ}C$. From the above results, the CaL-P and -A may believe to use as coagulant for tofu manufacture due to its softened taste and enhanced shelf-life, and higher calcium content which has higher absorbability in human body.