Kyung Hyung Ku

Dr. Kyung Hyung Ku

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
8 June 2017 in Applied Biological Chemistry
Verified
Journal Article
Open access
PDF file
Jihyun LeeJihyun Lee
Jihyun Lee
MJMoon-Cheol Jeong
Moon-Cheol Jeong
KKKyung Hyung Ku
Kyung Hyung Ku
The effects of 1-methylcyclopropene (1-MCP) on physicochemical properties and sensory characteristics of Fuji apple fruits stored at 2 °C for 9 months in air were investigated. The soluble solid content, titratable acidity (TA), sugars, sorbitol, organic acids, and phenolic compounds were evaluated in this study. We also determined volatile profiles using headspace solid-phase microextraction and gas chromatography–mass spectrometry. Instrumental textural properties and descriptive sensory analysis were also conducted in this study. The correlation coefficients between physicochemical and sensory properties were investigated. In comparison with the untreated apples, those treated with 1-MCP exhibited higher acidity (i.e., higher TA and organic acids), antioxidant total polyphenol content, sum of individual polyphenol content, force linear distance, lower volatile content, b* (yellowness), and fructose and sucrose levels, after long-term cold storage. A significant difference was observed in sensory attributes such as red color of apple peel, textural properties (with peel and without peel), sweet taste, and sour taste between 1-MCP-treated and untreated apples. Sensory attributes related to textural properties (i.e., P_Hardness and Crunchiness) showed positive correlation with instrumental textural properties (force peak and force linear distance) (p < 0.05). A significant positive correlation was observed between red color of apple peels (sensory attribute) and a* (redness) (p < 0.05) and between sour taste and shikimic acid (p < 0.05).

30 August 2008 in Journal of the Korean Society of Food Science and Nutrition
Verified
Journal Article
Closed access
KKKyung Hyung Ku
Kyung Hyung Ku
ECEun-Jeong Choi
Eun-Jeong Choi
JPJae-Bok Park
Jae-Bok Park

20 May 2020 in Antioxidants
Verified
Journal Article
Open access
PDF file
IKInhwan Kim
Inhwan Kim
KKKyung Hyung Ku
Kyung Hyung Ku
MJMoon-Cheol Jeong
Moon-Cheol Jeong
SKSoon-Il Kwon
Soon-Il Kwon
Jihyun LeeJihyun Lee
Jihyun Lee
Early- to mid-season apple cultivars have recently been developed in response to global warming; however, their metabolite compositions remain unclear. Herein, metabolites, such as free sugars, and organic acids and antioxidant activity were determined in 10 new and 14 traditional apple cultivars. Additionally, the phenolic profiles of the apple pulp and peel were characterized by high-resolution mass spectrometry. Major phenolic compounds in apples varied depending on the cultivar and tissue (i.e., peel or pulp). Among the new apple cultivars, Decobell and Tinkerbell, showed high antioxidant activity and contained higher phenolic compound content than other cultivars in the peel and pulp, respectively. Honggeum showed high phenolic content with similar sugar to acid ratio compared to popular traditional cultivars. In addition to antioxidant phenolic contents, metabolite profile information can be used to select apple cultivars for various purposes. For example, Indo can be selected for sweet apple taste because of its higher sugar to acid ratio. This information can be used to select apple cultivars for various purposes. For example, Decobell peel could be used as sources of food supplements and food additives, and Tinkerbell pulp can be utilized for apple juice making according to its metabolite profile.

31 March 2012 in Preventive Nutrition and Food Science
Verified
Journal Article
Open access
KKKyung Hyung Ku
Kyung Hyung Ku
KLKyung-A Lee
Kyung-A Lee
JPJae-Bok Park
Jae-Bok Park
This study investigated the heat level rating of several varieties of Korean red peppers. The chemical constitution of Korean red pepper samples were as follows: 0.54∼290.15 mg% capsaicinoids, 79.22∼139.09 ASTA value, and 16.76∼29.92% free sugar content. The heat level of the Korean red pepper samples was evaluated by trained panelists and the correlation coefficient and F value (0.001%) of the panelist's results were determined to be significant. In the principle component analysis (PCA), PC1 (capsaicinoids) and PC2 (free sugar) were shown to represent 31.98% and 25.77% of the total variance, respectively. The results of panelists trained for red pepper heat rating were evaluated using analysis of variance and correlation analysis. The trained panelists showed a high F value (p=0.05) and high correlation coefficient. A high correlation efficient of 0.84∼0.93 for the test samples with a 40 Scoville heat unit (32,000 SHU red pepper powder) was reported in the sensory evaluation of the Korean red pepper heat level by a trained panel. However, the panel showed a low correlation efficiency of 0.70 R(2) when the 60 SHU test samples were included in the analysis.

1 June 2015 in Korean Journal of Food Preservation
Verified
Journal Article
Open access
PDF file
ECEun Jeong Choi
Eun Jeong Choi
MJMoon Cheol Jeong
Moon Cheol Jeong
KKKyung Hyung Ku
Kyung Hyung Ku
This study investigates the physicochemical, microbiological and sensory characteristics of seasonal salted-Kimchi cabbages to provide basic data on its uniform quality. Generally, seasonal salted-Kimchi samples had different pH values at initial storage periods, but there was no difference in pH between the seasonal samples when stored for longer periods. The samples from the fall and winter seasons were relatively low in acid and high in solid soluble content compared to samples from other seasons. Salted-Kimchi cabbages in the summer showed the highest microbiological number compared to samples from other seasons. In the sensory evaluation, there were differences in the appearance, aroma, and taste, depending on seasonal samples at different storage periods. The correlation coefficient between the quality characteristics in the seasonal samples showed a positive or negative correlation between the quality characteristics at 1% significant level. In the principal component analysis, F1 and F2 were shown the 51.81% and 14.23% of the total variance (66.21%), respectively. In the PCA pattern of seasonal salted-Kimchi cabbages during storage periods, winter samples were distributed on the top of F2, spring samples were in the middle of F2, while the rest of the samples were distributed on the bottom of F2. According to increasing storage periods, initial storage samples were distributed at the left of F1, while other samples were located at the right of F2.

1 August 2014 in Korean Journal of Food Preservation
Verified
Journal Article
Open access
PDF file
KKKyung Hyung Ku
Kyung Hyung Ku
ECEun Jeong Choi
Eun Jeong Choi
MJMoon Cheol Jeong
Moon Cheol Jeong
This study was carried to investigate the physicochemical and microbiological characteristics of seasonal salted-Kimchi cabbage order to provide basic data for optimal salting and storage condition of seasonal Kimchi cabbage. Generally, fall season samples had slightly higher pH and acidity value than the other seasonal salted Kimchi cabbage. The soluble solids content of spring, summer, fall and winter samples were 5.95%, 6.18%, 6.29% and 7.76%, respectively. The salt content of all the seasonal salted Kimchi cabbage samples were insignificant. The number of microbial bacteria in the summer samples were generally much more significant than spring and winter samples. There was no significant difference in the color of seasonal salted Kimchi cabbage. As for the texture properties, the firmest samples in the surface rupture test were the spring samples (force: 4.92 kg), and the hardest samples in the puncture test were the summer samples (force: 11.71 kg). In the correlation analysis of the quality characteristics of seasonal samples, the soluble solids content and hardness of the seasonal salted Kimchi cabbage was significantly correlated at 1% significance level. Also, in the principal component analysis, F1 and F2 were shown to explain 27.28% and 35.59% of the total variance (62.87%), respectively. The hierarchical cluster analysis of the quality characteristics of seasonal samples, the samples were divided into three groups: spring cabbage group, summer cabbage group and fall and winter cabbage group,.