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

• The Korean Journal of Food And Nutrition
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• v.19 no.1
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• pp.22-27
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• 2006

This study was carried out to determine the optimum conditions for making soybean curd(or tofu) from defatted soybean flour.. Heating soymilk above $80^{\circ}C$ for at least $5{\sim}10\;min$ was necessary for soybean protein to form aggregates during subsequent coagulation process with glucono-${\delta}$-lactone(GDL). For maximum yield of tofu, with water content of approximately 80%, extra addition of 20 g of oil and 5 g of GDL per 425 g of soybean flour was needed. Maintaining soymilk temperature around $75^{\circ}C$ for 5 min was necessary when GDL was used as the coagulant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1130-1137
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• 2016

In this study, we investigated the quality, antioxidant properties, and sensory characteristics of tofu coagulated with 'Tsugaru' apple (Malus domestica Borkh) juice. Yield, $^{\circ}Brix$, pH, total acidity, total polyphenol content, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 'Tsugaru' apple juice were 60%, 10.3, 3.89, 0.51%, 2.26 mg gallic acid equivalent (GAE)/g, $20{\mu}g$ L-ascorbic acid equivalent (AE)/g, and $75{\mu}g$ AE/g, respectively. In case of Tofu coagulated with 20% (w/v) 'Tsugaru' apple juice, yield, $^{\circ}Brix$, pH, total acidity, hardness, chewiness, cohesiveness, total polyphenol content, ABTS radical scavenging activity, and DPPH radical scavenging activity were 165%, 6.23, 0.27%, 513 g, 315, 0.61, 12.04 mg GAE/g, $80.67{\mu}g$ AE/g, and $92.32{\mu}g$ AE/g, respectively. Both the manufacture yield and pH of tofu decreased with increasing amount of 'Tsugaru' apple juice, whereas total acidity increased. Regarding the texture and chromaticity of tofu coagulated with increasing amounts of 'Tsugaru' apple juice, hardness, chewiness, and a- and b-values increased, whereas cohesiveness and L-value both decreased. In terms of antioxidant activities, total polyphenol content and DPPH radical scavenging activity increased, whereas ABTS radical scavenging activity was maintained within a certain range. Finally, concerning the sensory evaluation (taste, color, flavor, and overall preference) of tofu coagulated with 30% (w/w) 'Tsugaru' apple juice showed the highest scores. Taken together, these results support the possible use of 'Tsugaru' apple juice in producing various foods, as addition of juice enhanced quality, antioxidant properties, and sensory characteristics of tofu.