• Journal of Life Science
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• v.27 no.11
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• pp.1299-1307
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• 2017

The quality characteristics of three non-genetically modified (GM) LRS soybean cultivars free of LOX 1, 2 and 3, such as Jinyang, Hayoung and Daebok, were compared to the characteristics of Taekwang, a soybean with LOX 1, 2 and 3 and general contents of raffinose and stachyose. Taekwang was used as a control soybean. The weights of 100 for Taekwang and Hayoung soybeans were significantly higher than those of the other samples. The crude-protein contents of the Jinyang and Hayoung soybeans were significantly higher than the crude-protein content of the Taekwang soybeans. Similar tofu yields were observed in the Taekwang, Hayoung and Daebok soybeans. The highest tofu yield was observed in the Hayoung soybeans. The isoflavone contents of the soybeans and tofu were 1.4-1.6 times and 1.8-3.4 times higher than the contents of the control soybeans, respectively. The total phenol contents of the Hayoung and Daebok soybeans were significantly higher than the contents of the control soybeans. Additionally, the total phenol and flavonoid contents were significantly higher in the tofu made from the LRS cultivars than in the tofu made from the control cultivar. The antioxidant activities of the Taekwang soybeans were higher than the antioxidant activities of the LRS-cultivar soybeans. However, the antioxidant activities of tofu made from the LRS cultivars were significantly higher than the antioxidant activities of tofu made from the control cultivar. The results suggested that the soybeans of the LRS cultivars were suitable for tofu products. The Hayoung cultivar may be the most suitable due to its higher crude protein and isoflavone contents and its significant antioxidant activity.

• 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 Science and Nutrition
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• v.22 no.3
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• pp.255-261
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• 1993

The effect of dried soymilk residue (DSR) on protein quality of tofu was studied. The amount of added DSR into soybean water extract was corresponding 10% (dry basis) of soybean used in tofu manufacturing. Proximate composition and in vitro protein qualities of soybeans at different stages of the conversion into tofu have also been investigated. Partially substituted tofu with DSR (TDSR) had higher moisture content (80.6%) than that of tofu prepared in traditional manner (TT). TDSR contained lower content of protein (38.9%) and total lipid (26.9%) compared to 45.8% of protein and 34.3% of total lipid for TT. A large amount of trypsin inhibitor (TI) in raw soybeans was diminished and extracted through tofu processing, and only 10~13% of TI in raw soybean remained in both tofu products (TDSR and TT). There was not a considerable difference in amino acid profiles between TT and TDSR, but TDSR had a higher content of lysine than that in TT. in vitro studies showed that TDSR and TT were comparable in terms of both in vitro digestibilities (90% over for four-enzyme digestibility and predicted digestibility) and discriminant computed protein efficiency ratio (2.07~2.14, DC-PER). Unlike those in vitro indices for protein quality, computed protein efficiency ratio (C-PER) of TDSR was much lower (1.4) than that of TT (1.95). It was revealed that C-PERs of tofu products were not in agreement with rat-PERs (1.7~1.9) in previous reports except for TT. However, DC-PER assay was more recommendable for protein quality of tofu products than C-PER assay.

• Applied Biological Chemistry
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• v.26 no.4
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• pp.205-210
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• 1983

To investigate the characteristics of amino acid fortified tofu manufactured by coprecipition of cheese whey and soybean proteins, experimental tofus were made from various mixtures of whey, whey powder, and soy milk, and general and amino acid compositions and physical properties were analyzed. Physical characteristics such as elasticity, hardness, and brittleness of the whey-soybean tofu were very similar to those of traditional tofu but color of the whey-soybean tofu was lighter than that of soybean tofu. The contents of total solids and protein of traditional tofu were about 19% and 13%, respectively, while those of the whey-soy bean tofus were 17.3%$\sim$18.1% and 10.9$\sim$11.3%, respectively. The 5$\sim$15% of lactose in whey-soymilk mixture was transferred into the tofus. The Content of sulfur-bearing amino acids in the fortified tofu from 3 : 1 mixture of whey and soymilk was 3.8g/100g protein which indicated about 50% fortification of the amino acids as compared to the traditional tofu which contained 2. 54g/100g protein of the sulfur-bearing amino acids.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.123-128
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• 2012

This study was conducted to investigate the quality characteristics of tofu (soybean curd) prepared with added alfalfa extracts (Medicago sativa L.). The moisture content, yield, and pH of tofu decreased according to the increase of an added quantity of alfalfa extract, whereas the crude protein and turbidity increased. The tofu made with additional alfalfa extracts gave a similar amount of crude ash with that of the control. The Hunter's L (lightness) color value decreased as the content of alfalfa extract increased, but the a (redness) and b (yellowness) values increased with increasing alfalfa extract concentration. Textural properties for hardness were higher but cohesiveness, springiness, gumminess, and brittleness were lower in alfalfa extracts with added tofu compared to those of control. Isoflavones such as daidzein and genistein content were significantly increased with increasing concentration of alfalfa extracts. A sensory evaluation indicated that the group with a 0.5% alfalfa extract showed the best color, flavor, taste, and overall acceptability results. In conclusion, adding alfalfa extracts could improve the physicochemical and sensory characteristics of tofu.

• Culinary science and hospitality research
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• v.18 no.5
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• pp.293-304
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• 2012

This study was conducted to improve the sensory acceptability of modified Kochujang added with Tofu powder(25%, 50%, 75%, 100%) instead of Meju powder. These Kochujang samples were fermented for 45 days and examined in physicochemical properties and sensory characteristics. The result was as follows. Moisture content of the control was higher than that of the other Tofu powder Kochujang samples, which lasted for 30 days of storage. Moisture contents of all samples were increased by storage time. The pH of Kochujang added with Tofu powder was higher than that of the control. In general, pH values were decreased by storage time. Acidity decreased with Tofu powder increased while it generally increased with more storage time. In the lightness(L value), redness(a value) and yellowness(b value), control Kochujang was the lowest. There were no significant differences in the reducing sugar contents except 45 days. In sensory evaluation, color of Kochujang was evaluated light and off-flavor got weaker with Tofu powder increased. In the sensory attributes of odor, taste, overall acceptability, Tofu powder added Kochujang had high scores than the control, and especially 100% TP Kochujang had the best score.

• Food Engineering Progress
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• v.21 no.1
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• pp.72-78
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• 2017

The objective of this study was to investigate the effects of combinations of tofu paste and non-starch polysaccharides (NSP) on the oil uptake reduction (OTR) of deep-fat fried cake doughnuts. OTR agents were tofu paste (from grinding tofu with deionized water, followed by passage through a 60 mesh sieve), and five neutral and nine anionic NSPs. A control doughnut (without tofu paste or NSP), tofu doughnut (with tofu paste) and NSP-tofu doughnut (with tofu paste and NSP) were prepared. The moisture and total lipid (TL) content, cross-section image, color characteristic, and specific volume were measured. The tofu and NSP-tofu doughnuts exhibited higher moisture and lower TL content than the control. OTR was 10.8% for the tofu doughnut, and between 13.2% and 41.2% for the NSP-tofu doughnut. The highest OTR (41.2%) was found in the NSP-tofu doughnut with a combination of tofu paste and sodium alginate (NaA). The specific volume of the NSP-tofu doughnuts with combinations of tofu paste with NaA (2.5 mL/g), locust bean gum (2.5 mL/g), and ${\kappa}$-carrageenan (2.4 mL/g) was very close to that of the control (2.6 mL/g). Considering the OTR and specific volume of doughnuts, the combination of tofu paste and NaA would be most effective in reducing the oil uptake of doughnuts during deep-fat frying.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.262-265
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• 1993

Dietary fiber content and carbohydrate digestibility of dried soymilk residue (DSR) and tofu containing DSR were evaluated. Insoluble dietary fiber (IDF) content was 37.4 and 49.8% (%, moisture free basis) for common soymilk residue and DSR, respectively. Both soymilk residues contained 12.5% of soluble dietary fiber (SDF, dry basis). Tofu containing DSR, which is partially substituted with DSR corresponding to 10% weight of soybean used, had higher dietary fiber content (30% more for RDF and 45% more for SDF) than tofu manufactured in traditional manner. Carbohydrate digestibility was much lower in all tofu products ranging from 11% to 21%, and there was a negative correlation( r = -0.9243) between carbohydrate digestibility and total dietary fiber content.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.12-15
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• 2003

The effect of chlorella addition on quality and shelf-life of soybean curd was investigated. The yield of chlorella soybean curd was the highest with 1.0% (w/w) chlorella addition. Hardness, gumminess, and chewiness of chlorella soybean curd increased, whereas Hunters color values decreased in proportion to amount of chlorella added. No significant differences were observed between the sensory properties of chlorella and ordinary soybean curds. Microbial counts of soybean curd stored in sterilized distilled water as tofu-immersion solution increased, whereas pH decreased during storage at $15^{\circ}C$. After 5 days storage, microbial counts of the soybean curds containing 0.5 and 1.O% chlorella were lower than that of the ordinary soybean curd. These results imply that chlorella is a useful additive to suppress the proliferation of aerobic microorganism in soybean curd at the optimal concentration of chlorella around 1%.