• Journal of the Korean Society of Food Culture
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• v.34 no.5
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• pp.629-636
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• 2019

This study examined the quality characteristics of jelly prepared with green grape juice (GJ). The pH, $^{\circ}Brix$ value, color, texture, and sensory evaluation of the jelly were measured. The pH of the jelly significantly decreased with increasing amount of GJ over the range of 3.25-5.27. The $^{\circ}Brix$ value of the jelly showed a significantly higher result as the amount of GJ increased (p<0.001). Lightness (L) and redness (a) decreased with increasing amount of GJ, and yellowness (b) increased. In the texture measurement, the GJ-100 sample group with a high substitute rate of GJ showed high hardness, gumminess, and chewiness (p<0.001). The results of principal component analysis (PCA) showed that the sample groups with high GJ content were classified as having relatively strong yellowness, sweet aroma, metallic aroma, grassy aroma, sweetness, sourness, green grape skin taste, and astringency. In the acceptance test, the GJ-50 sample group was evaluated to be high in flavor (p<0.001) and overall acceptance (p<0.01). However, sample groups consisting of 50% or more GJ were evaluated to be significantly strong in terms of astringency. Therefore, further study needs to be conducted about improving astringency in the future.

• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.272-277
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• 2018

This research was conducted to elucidate the optimum conditions for the antibacterial activity of konjak jelly using the evolutionary operation-factorial design technique. In the first set of experiments, concentration of a coagulation agent, soaking liquid, and temperature of water were set to 0.4%, $0.6{\times}10^{-2}N$, and $65^{\circ}C$ as a central point, respectively. The highest antibacterial activity was acquired at E21, in which the number of bacteria was 1.25 log cfu/g. Because the code of changes in the main effect was (-), it could be decided that the central point of the first set was not the optimum point. Although antibacterial activity in the second set was improved, the values of the main effect were higher than that of changes in the mean effect. The central point of third set was concentration of coagulation agent 0.8%, concentration of soaking liquid $1.0{\times}10^{-2}N$, and temperature of water $65^{\circ}C$. It was found that the antibacterial activity of central point in the third set was highest among all the tested set. Further, all the necessary conditions were appropriate to reach the optimum condition. The antibacterial activity of the central point in third set was more than 1,000 times higher than that of E11, in first set.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.446-453
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• 2021

This study examined the antioxidant activities of noni juice (NJ) extracts using various ethanol ratios and quality characteristics of Konjak jelly (KJ) supplemented with NJ. The total polyphenol content of 0% EtOH extract (EE) was higher than that of the other samples. The 100% EE contained the highest amount of total flavonoids. The 50% EE showed higher DPPH radical scavenging activity (SA) than the other samples. ABTS⁺ radical SA was the highest at 100% EE. The pH and moisture content of KJ decreased as the amount of NJ increased. The sugar content of KJ increased with an increase in the amount of NJ. Hardness and gumminess showed an increasing tendency, while L and b values decreased with the addition of NJ. Regarding consumer acceptability, 25% noni KJ was evaluated to be high in color and flavor. As a result, KJ containing 25% NJ was suitable for increasing consumer acceptability and functionality of KJ.