• Journal of the Korean Society of Food Culture
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• v.29 no.5
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• pp.415-420
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• 2014

This study was conducted to establish optimum conditions for coagulation of konjac jelly as well as antimicrobial activity by concentration of $Ca(OH)_2$. Hardness, gumminess, and chewiness of konjac jelly increased according to concentration of konjac powder, the key material of konjac jelly. The highest sensory evaluation score was acquired with konjac jelly made with 3% konjac powder. A $Ca(OH)_2$ concentration of 0.4-0.6% as a coagulation agent was optimum for coagulation of konjac jelly. Further, sensory score was highest at a $Ca(OH)_2$ concentration of 0.6%. All populations of bacteria, yeast, and mold in konjac jelly were restrained by $Ca(OH)_2$ in a concentration- dependent manner. Furthermore, all tested microorganisms were strictly restrained at $1.0{\times}10^{-2}$ N of $Ca(OH)_2$.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.587-594
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• 2020

In this study, we examined the effects of various hydrocolloid (alginate, carrageenan, and konjac) treatments on the quality characteristics of cold-cut duck meat jelly. Seven different types of cold-cut duck meat jelly were prepared: control, without hydrocolloids; T1, 0.5% alginate; T2, 0.5% carrageenan; T3, 0.5% konjac; T4, 0.25% alginate + 0.25% carrageenan; T5, 0.25% carrageen + 0.25% konjac; and T6, 0.25% alginate + 0.25% konjac. The pH and moisture content of the cold-cut duck meat jelly with hydrocolloids was higher (p < 0.05) than that of the control. The highest lightness value was recorded for T4 and T6 (p < 0.05), and the hardness was lower (p < 0.05) in the meat jelly with hydrocolloids than in the control, except for T2 and T5. The springiness of the meat jelly was the highest (p < 0.05) in T1 and T4. The onset, peak, and end temperatures were the lowest (p < 0.05) in the control. The highest appearance score of the meat jelly was observed in T6, and its overall acceptability was higher (p < 0.05) than that of the control, indicating that, of all the treatments, 0.25% alginate + 0.25% konjac yielded the most desirable results. Thus, the combined use of duck skin and gelatin with alginate and konjac is potentially applicable for the development of new cold-cut duck meat products.

• Korean journal of food and cookery science
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• v.24 no.2
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• pp.174-181
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• 2008

The purpose of this study was to determine the optimal mixing conditions for different amounts of konjac(0.2, 0.3, 0.4, 0.5, 0.6%) and carrageenane(0.8, 1.0, 1.2, l.4, 1.6%) in the preparation of citrus jelly, using the central composite design. The results showed that the sensory and mechanical characteristics of the jelly increased with decreasing konjac and carrageenane contents. Overall optimal conditions that satisfied the rheology, appearance characteristics and sensory properties of the citrus jelly were 0.2% konjac, 1.2% carrageenane and 30minutes of heating time using citrus juice of $20^{\circ}C$Brix and 0.3% citric acid.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.699-705
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• 2014

This study was conducted to select the coagulant for konjac processing and to identify the antibacterial activity on foodborn pathogens by concentration of $Ca(OH)_2$. In rheological properties such as hardness, gumminess and chewiness, konjac jelly were increased by progressing coagulation regardless of coagulant. In mineral contents, the Ca content of konjac jelly made with $Ca(OH)_2$ was significantly higher than that of NaOH. On the contrary, the Na content of konjac jelly made with NaOH coagulant was significantly higher than that of $Ca(OH)_2$. There were no significant differences in the Mg and P contents according to coagulant. In sensory evaluation, there were no significant differences in the color, flavor, taste, texture and overall quality according to coagulant. The antimicrobial activities of Staphylococcus aureus, E. coli, Salmonella typhimurium were inhibited in proportion to the concentration of $Ca(OH)_2$. According to the manufacturing process of konjac jelly, the change in microorganism was not found after molding.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.613-618
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• 2021

The quality characteristics of jelly-containing vinegar drinks were divided into three stages in this study. The jelly, which differs from the contents of the vinegar drink, sharply decreased the pH. After sterilization, hardness was significantly decreased, and the formulation was not maintained, which was considered the effect of low pH and high total acidity of vinegar drinks. Different experiments confirmed that pH and sterilization heating conditions were the major quality variables for gelation as both sodium citrate content and jelly hardness were correlated before and after sterilization. The hardness of the jelly, which differs in gel content, correlated with the increase in gelation content both before and after sterilization. Therefore, considering the spout jelly of a vinegar drink, pH of 3.5-3.7 and a content of glucomannan and caragenane mixed gel were considered appropriate to match the product's sensory properties.

• Journal of Food Hygiene and Safety
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• v.35 no.2
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• pp.183-188
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• 2020

The manufacturing process for konjac jelly is largely divided into the three processes of powder manufacturing, a coagulation and finishing. It was found that the number of aerobic bacteria in konjac jelly decreases as the concentration of coagulation agent and soaking liquid increases. The temperature of the water has no significant effect. When the concentration of coagulation agent was maintained at 1.0%, the tensile strength was also maintained without significant change for up to 10 months. When the concentration was kept below 0.8%, however, the tensile strength showed a tendency to sharply decrease. After fixing the coagulant concentration to 1.0%, the effect by the soaking liquid was confirmed. At all concentrations of soaking, it was found that both tensile strength and bacterial numbers are unchanged until 10 months of storage.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.100-105
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• 2019

In this study, viable cells, coliforms and food poisoning bacteria were identified according to the pH levels of the coagulant and immersion liquid during each stage in the production of konjac, and storage stability was confirmed for 3 months. A considerable number of bacteria were found in the raw material, or powdered konjac (Amorphophallus konjac), as well as in the processing water. However, it has been shown that the plastic package were safe from microorganisms. Due to the high pH of the added coagulant [2.0% $Ca(OH)_2$], no contaminating bacteria were observed after konjac jelly formation. Coliforms were not detected any of the tested steps. During the molding process, the pH of konjac was adjusted to 9.5 ~ 12.5 at intervals of 0.5, and the number of bacteria was determined. As a result, no bacteria were detected in the alkaline range above pH 11.5. The pH of the immersion liquid was adjusted to 10.0 ~ 12.5, and after hardening, the konjac were stored at room temperature for 12 weeks. As a result, no bacteria, Escherichia coli or other food poisoning bacteria were detected at pH 11.5 or higher. Based on these results, it is expected that when the pH levels of the konjac and its immersion liquid are maintained at 11.5, it should be possible to keep the product for 3 months without additional sterilization process.