• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.9-14
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• 1984

This research aims to increase the extent of utilization of soybean curds coagulated with $Glucono-{\delta}-lactone$ (GDL) as a protein soarce by analyzing nutritive guality and preference to them. The curds were made from two kinds of soybean, domestic and imported. The results were as follows; 1. The yield of the domestic soybean curd was higher than that of the imported. 2. The total nitrogen and amino acid content of the GDL soybean curd were higher in the do- mestic while lipid and ash were higher in the imported one. 3. Rheological properties such as hardness, toughness, springiness and chewiness were higher in the domestic soybean curds than those of tile imported. 4. The 'L' values of the GDL soybean curds were higher in the domestic. However, there were no significant differences in the 'a' and 'b' values between the domestic and the imported soybeans. 5. According to the organoleptic the GDL soybean curds were not so favorable to our preferences .

• 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.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.370-378
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• 1994

Soybean curd added with 40% of cow’s milk was prepared with eight coagulants such as calcium acetate, calcium lactate, calcium chloride, calcium sulfate, magnesium chloride, glucono-delta lactone (GDL), acetic acid and lactic acid. The curd products were evaluated by the chemical composition, coprecipitation porperties, mineral content, yield, color and textural characteristics. The lowest concentrations for protein coprepitation were 0.3% (v/v) for calcium salts, 0.4% (v/v) for magnesium chloride, 0.2% (v/v) for organic acids. Turbidity and crude protein of whey were markedly decreased at these concentrations. The optimal concentrations of coagualnts used for soybean curd preperation were 1.2% (v/v) for calcium acetate, calcium sulfate and calcium lactate, 1.0% (v/v) for calcium chloride and GDL, 0.8% (v/v) for magnesium chloride and lactic acid, 0.6% (v/v) for acetic acid. It was observed that of the eight coagulants tested, calcium chloride provided a satisfactory curd in quality. Calcium content of soybean curds by the calcium salt coagulants was higher than that by organic acid coagulants. Through the examination on the textural properties by a texturemeter was found out that acetic acid treated soybean curd among the organic acids, calcium salts and magnesium chloride treated curds had very high hardness value. All the curd products prepared in this experiment had a pale yellow color as affected by the value of L (lightness), a (redness) and b (yellowness). Although the colorimetric readings showed that the soybean curds prepared with the organic acids had higher L value but lower a and b value in comparison to calcium salts and magnesium chloride treated curds.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.664-671
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• 2013

The objective of this study was to investigate the effect of high pressure treatment and type of binding agents on the quality characteristics of restructured pork. For binding agents, 2% (w/w) isolated soy protein (SP), 0.5% (w/w) wheat flour (WF) and 0.5% (w/w) ${\kappa}$-carrageenan (KC) were incorporated into meat batter with or without 0.5% (w/w) glucono-${\delta}$-lactone (GdL). The restructured pork was pressurized at varying pressure levels (0.1-450 MPa) for 3 min under ambient temperature and thermal treated at $75^{\circ}C$ for 30 min. As quality parameters of restructured pork, pH, water binding properties, instrumental color and texture profile analysis were determined and compared with control (C, no binder). For type of binders, SP exhibited the best water binding properties, however, the impact on textural properties were lesser than KC and WF. The addition of GdL decreased the pH of restructured pork down to 0.4 unit, while high pressure processing prevented the moisture loss caused from pH decrease by GdL. In particular, meat restructuring efficiency of SP as a binder improved under the presence of GdL. Therefore, the present study demonstrated the potential advantages of low amount of GdL (0.5%, w/w) combined with protein based binder (SP) and high pressure processing in restructuring meat particles.

• Korean Journal of Food Science and Technology
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• v.28 no.5
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• pp.965-969
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• 1996

An investigation was carried out to elucidate the effects of type of ginseng, concentration of ginseng, and type of coagulants on the physical and sensory properties of soybean curd. The textural properties of soybean curd were not influenced by the type of ginseng. Soybean curd coagulated with glucono-delta-lactone (GDL) showed a greater hardness than that coagulated with other coagulants, whereas the former produced a lesser springiness than the latter. The L-value was proportionally reduced by the increase of ginseng level and soybean curd coagulated with $CaCl_2$ showed the lowest L value. All the curd products prepared with ginseng had a pale yellow color. In the sensory properties, springiness and beany taste of soybean curd linearly decreased as the concentration of ginseng was increased. The concentration of ginseng to improve the acceptability of ginseng soybean curd as determined by the physical and sensory evaluation, was less than 0.25%. The most acceptable ginseng soybean curd was the one coagulated with $MgCl_2$. Soybean curd prepared with GDL had the lowest acceptability because of its sour taste and textural properties.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.42-48
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• 1992

The rate and extent of coagulation of milk using fast acidification with 0.1 N HCl were monitored by changes in viscosity and turbidity at various temperatures and pH. Also the gelation rate of milk using slow acidification with D-glucono-${\delta}$-lactone was measured in a small strain rheological scanner. Coagulation of milk casein occurred in a specific pH range and was accompanied by an abrupt increase in viscosity at pH 5.0. Acid coagulation rate was enhanced by increasing temperature from $20^{\circ}C{\sim}50^{\circ}C$, and the maximum rate was shown around pH 5.0. The addition of salt ($CaCl_{2}$) reduced the maximum coagulation rate at all temperature ranges and shifted the pH ranges for maximum coagulation rate and the onset pH of coagulation. The onset of gelation and the rate of network formation during slow acidification were facilitated by Cl ion, but suppressed by SCN-ion, as indicated by the rate of rigidity development. The susceptibility to syneresis was greater in the gel made at lower temperature and around pH 4.6, while preheated milk at $90^{\circ}C$ for 5 min prior to acidification showed the same syneresis profile at all heating temperatures ($60{\sim}90^{\circ}C$).

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.652-660
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• 2002

To develop natural food preservatives for extending the shelf-life of jeotkal (salted and fermented seafood), antimicrobial substances were extracted from 32 types of medicinal herbs and edible plants using 95% ethanol. Among the extracts, Glycyrrhizae radix, Curcumae domestica, Galla rhois, and Resina pini showed relatively high inhibitory effects on the growth of the microorganisms isolated from the deteriorated jeotkal. We selected and tested the extract from Recina pini as a natural jeotkal preservative. This ethanol extract was purified partially by adding equal quantity of water, through which 77% of insoluble materials were removed as impurities. In manufacturing modified jeotkal using squid, sucrose and starch syrup were substituted with sorbitol, $glucono-{\delta}-lactone$ was added instead of vitamin C and lactic acid, and sterilized hot pepper was used instead of natural one. The shelf-life of modified jeotkal was prolonged by 4 days compared with the control jeotkal when stored at $20^{\circ}C$, while that of modified jeotkal containing 1.0% partially purified Recina pini extract was prolonged by 6 days compared to the control. The same tests were conducted for the changran (stomach and intestine of Alaska pollack) jeotkal preservation. The shelf-life of the control jeotkal was 24 days, whereas the modified jeotkal and the Resina pini extract-containing modified jeotkal maintained their qualities without changes in microbial and chemical characteristics for 90 days at $20^{\circ}C$ storage.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.402-409
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• 2000

To investigate the textural and physical characteristics of WSF(whole soybean flour) tofu affected by coagulant and its concentration, $CaCl_2$, $CaSO_4$, $GDL(glucono-{\delta}\;lactone)$, $MgCl_2$, and some mixed coagulants were used in this study. Yields of WSF tofu coagulated with $CaSO_4$ and GDL were ranged 4.3-4.5(g/g WSF), but common tofu was 2.2-3.0(g/g soybean). As the water addition ratio increased, L and a value were increased while heating time increased, b value increased. L value of WSF tofu was lower and b value was higher than conventional tofu and 4 commercial tofus. Kinds of coagulant and its concentration significantly affected to textural properties of WSF tofu. As the concentration of coagulant increase, the hardness increased in most all coagulants. WSF tofu coagulated with $CaSO_4$ and GDL recorded low hardness and adhesiveness, and high springiness among the used coagulants at the same concentration. As the hardness increased, the gumminess and chewiness increased in most all coagulants. As coagulation temperature and molding pressure increase, hardness also increased. WSF tofu coagulated with 0.3% $CaSO_4+GDL$ was the most similar in the textural properties with conventional tofu and 4 commercial tofus. WSF tofu coagulated with 0.3% of $CaSO_4+GDL$ at $85^{\circ}C$, 10 times water addition, 5min. heating and $25.0g/cm^2$ molding pressure recorded the highest score in the sensory evaluation.