• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.298-303
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• 2010

This study was carried out to compare the physicochemical characteristics of Korean traditional wine fermented from foxtail millet and nuruk at different mixing rates. The alcohol contents of fermented wine ranged from 12.70 to 13.38%. Two kinds of commercial nuruks, SH and BS nuruk, were used. The brix degrees of foxtail millet wine fermented by SH and BS nuruks were 21.6 and $22.4^{\circ}Bx$, respectively. The pH, total acidity, and turbidity of the wines fermented by SH and BS nuruks were 3.74 and 3.40, 1.40 and 1.51%, and 0.441 and 0.149, respectively. With an increase in the amount of foxtail millet, brix degree, pH, turbidity, b-value and L-value decreased, and total acidity and a-value increased. Total color difference (${\Delta}Eab$) parameter of the wine fermented by SH nuruk were 8.58, 22.59 and 22.55, while those by BS nuruk were 0.35, 4.08 and 7.16 in 30, 70 and 100% addition rates of foxtail millet, respectively. With an increase in the amount added of foxtail millet, glucose content decreased. The organic acids such as lactic acid and acetic acid were predominantly detected in the fermented wine. Finally, based on sensory evaluations, the wine fermented by BS nuruk showed the best overall quality at the 30% addition rate of foxtail millet.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.263-268
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• 2010

This research was conducted to evaluate the occurrence of ochratoxin A (OTA) in coffee and fruit products in Korea. A total of 388 coffee and fruit product samples were collected from retail or outlet markets; 177 samples were coffee and 211 were fruits or their products. Analytical methods including AOAC and Comit$\acute{e}$ Europ$\acute{e}$en de Normalisation (CEN) were selected and modified by method validation to detect and quantify the OTA in samples. All samples were analyzed by liquid chromatography with fluorescence detection. OTA was detected in 3.9% of 177 kinds of coffee and 0% of 211 kinds of fruit products. The levels of OTA were $0.7-4.6\;{\mu}g/kg$ in green coffee, $0.3-4.8\;{\mu}g/kg$ in roasted coffee, $1.4\;{\mu}g/kg$ in mixed coffee, and $0.4-0.6\;{\mu}g/kg$ in instant coffee. However, OTA was not detected in liquid coffee, dried fruits, or grape juice. OTA levels of all samples detected were less than the European Union legislation of $5.0\;{\mu}g/kg$ in coffee, $10.0\;{\mu}g/kg$ in raisins and $2.0\;{\mu}g/kg$ in grape juice. Therefore, the risk of OTA in coffee and fruit products in Korea is relatively low at safe levels.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.420-429
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• 2018

Skin ageing is associated with compromised performance of its fundamental barrier functions, with undesirable changes in appearance. Since this may introduce a detrimental impact on the quality of life, significant effort to discover effective ingredients against ageing is being invested. Recently, collagen hydrolysates containing tripeptides such as GlyPro-Hyp (GPH) have been developed with anticipation of improved effects compared to that of existing collagen hydrolysate-products. To evaluate the cutaneous hydration effect of collagen tripeptides (CTP), meaningful biomarkers in human dermal fibroblasts (HDF) and NC/Nga Tnd mice were analyzed in this study. Increased levels of ceramide kinase, hyaluronic acid, collagen 1A, and hyaluronan synthase-2 (HAS2), and decreased levels of hyaluronidase-1 (HYAL1) and CD44 in HDF cells were demonstrated. Furthermore, significant reduction of transepidermal water loss (TEWL), scratching behavior, HYAL1, $TNF-{\alpha}$ and IL-6 and increased water content and HAS2 were verified by in vivo tests. These results strongly suggest the potential of CTP as a skin hydration agent.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.210-218
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• 2015

Melon leaves showing yellowing symptoms were analyzed using electron microscopy and RT-PCR for major cucurbit-infecting-viruses (CMV, MNSV, CGMMV, SqMV, WMV, KGMMV, PRSV and ZYMV) reported in Korea, but these viruses were not detected. As the result of further analysis by next-generation sequencing (NGS), the virus was identified as Cucurbit aphid-borne yellows virus (CABYV), and then confirmed by RT-PCR using CABYV-specific primers. When photosynthetic capacity was measured based on chlorophyll fluorescence yield (ChlFY), the leaves of the diseased plants showed $4.09{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, which was one-third of the readings observed for unaffected normal plants ($12.36{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). The root functions of plants affected by leaf yellowing symptoms (LYS) was $0.28mg{\cdot}g^{-1}$, about half that measured for the normal unaffected plants ($0.48mg{\cdot}g^{-1}$). Cytological observations revealed that there were no morphological differences in the palisade parenchyma and mesophyll spongy cells of the leaves between the diseased and the normal plants. However, the same leaf cells of the affected plants contained more starch granules compared to those of the normal, unaffected plants. We conclude that the LYS of muskmelon is not merely a physiological disorder but a viral disease caused by CABYV and spread by aphids.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.283-291
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• 2015

The aim of this study was to evaluate the changes of fruit quality, flavonoid contents and antioxidant activity of Yuzu (Citrus junos Sieb. ex Tanaka) from Go-heung and Jeju according to harvest time. Samples were harvested from August to December on the $1^{st}$ of every month. August and September samples were green colored, whereas November and December samples were yellow. The fruit shape index decreased, changing from globular to elliptical, whereas the $^{\circ}birx$ increased with ripening stage. The yuzu from Jeju was larger than that from Go-heung in each month of cultivation. August samples exhibited the highest amounts of phenolic compounds. In addition, samples from Jeju had higher total phenolic content than those from Go-heung. The content of phenolic compounds decreased with ripening until October and then increased subsequently. Antioxidant activity of the yuzu was evaluated by FRAP and DPPH methods. The antioxidant activity showed a similar trend as total phenolic content. Immature yuzu fruit was found to exhibit the highest amount of flavonoids such as naringin and hesperidin. November and December samples showed almost the same contents of flavonoids. The flavonoid content of yuzu fruit harvested from Jeju was higher than that from Go-heung. Overall, the samples harvested at the early stage, in the month of August, exhibited the highest flavonoid content, phenolic content and antioxidant activity. As the health benefits of these compounds has been demonstrated in various studies, the immature yuzu appears to be preferable for use as a raw material for formulation of pharmaceutical products as well as for functional food production after a proper in-vivo and in-vitro medical tests.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.186-195
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• 2015

This research was conducted to investigate effect the plant growth regulators (PGRs) on the characteristics of fruit and flesh softening, using GA3 and thidiazuron (TDZ) treatments in 'Heukboseok' grapes. The total yield obtained under PGR treatment was 88.3% lower than the target production when a single treatment with $GA_3$ of low concentrations was used, but the expected yield was recovered by combined treatment with TDZ and $GA_3$. When harvested on the basis of color, the harvest rate up to 100 days after full bloom (DAFB) was low with the $GA_3$ single treatment, but was increased by the addition of TDZ, with the second TDZ mixed treatment being particularly effective. The soluble solids content in the PGR-treated samples demonstrated no significant changes after 90 DAFB, while the acidity content decreased rapidly starting from 90 DAFB. Measured on the basis of sugar and acidity content, maturity was reached much earlier in treated fruit than in the non-treated fruit. Firmness was maintained at a higher level until the final harvest time after PGR treatment compared to untreated grapes according to epidermis thickness and flesh density increase to activity cell division and expansion by $GA_3$ and TDZ. In particular, the fruit quality was improved based on the delay of softening in primary and secondary treatments of $25mg{\cdot}L^{-1}\;GA_3+2.5mg{\cdot}L^{-1}$ TDZ. The production of seedless fruit was difficult, even with the inclusion of TDZ, reaching the highest seedless rate of only 65.5%. Fruit cracking was rare, occurring at a rate of about 0.0~0.9% in all treatments. Accordingly, 'Heukboseok' grapes should be harvested within 100 days after full bloom (DBFB) before a rapid decrease of firmness, conferred by primary and secondary treatments with $25mg{\cdot}L^{-1}\;GA_3+2.5mg{\cdot}L^{-1}$ TDZ.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.366-373
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• 2011

To analyze the genetic relationships among Korean potato cultivars and to develop cultivar identification method using DNA markers, we carried out genotyping using simple sequence repeats (SSR) analysis and developed multiplex-SSR set. Initially, we designed 92 SSR primer combinations reported previously and applied them to twenty four Korean potato cultivars. Among the 92 SSR markers, we selected 14 SSR markers based on polymorphism information contents (PIC) values. PIC values of the selected 14 markers ranged from 0.48 to 0.89 with an average of 0.76. PIC value of PSSR-29 was the lowest with 0.48 and PSSR-191 was the highest with 0.89. UPGMA clustering analysis based on genetic distances using 14 SSR markers classified 21 potato cultivars into 2 clusters. Cluster I and II included 16 and 5 cultivars, respectively. And 3 cultivars were not classified into major cluster group I and II. These 14 SSR markers generated a total of 121 alleles and the average number of alleles per SSR marker was 10.8 with a range from 3 to 34. Among the selected markers, we combined three SSR markers, PSSR-17, PSSR-24 and PSSR-24, as a multiplex-SSR set. This multiplex-SSR set used in the study can distinguish all the cultivars with one time PCR and PAGE (Polyacrylamide gel electrophoresis) analysis and PIC value of multiplex-SSR set was 0.95.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.317-325
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• 2011

This study was conducted to examine the effect of supplemental lighting on the growth and yield of hydroponically grown sweet pepper (Capsicum annuum L. cv. sprit) under low levels of natural light in winter. The plants were treated with natural light only (control), 3-hour supplemental lighting before sunrise, after sunrise and after sunset with high pressure sodium (HPS, 400W). As the result of these three treatments, the supplemental lighting promoted photosynthesis in the low light intensity condition and particularly photosynthesis was more active right after sun rise in the morning, 1.5-$3.0{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$ comparing to those of supplemental lighting after sunset, 0.5-$1.5{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$. Transpiration rate and stomatal conductance sharply increased with supplemental lighting after sunrise then they decreased again after turning the lights off. Stomatal size was observed $32.2{\mu}m^2$ after supplemental lighting, whereas the size of the natural light was almost closed at $7.7{\mu}m^2$. The average plant height of sweet papper cv. spirit was 185 cm before sunrise, 188 cm after sunrise and 208 cm after sunset with supplemental lighting for 3hours while the control was 171 cm. With supplemental lighting a better number of fruit set per plant was measured 4.3 before and after sunrise, 3.7 after sunset but 2.6 in the control. Interestingly, there were no significant differences in the sugar content ($^{\circ}Brix$) degree between treatment of supplemental lighting, whereas slight differences between seasons were seen. The marketable fruit yield of sweet pepper (cv. spirit) was $116.0kg{\cdot}ha$ with supplemental lighting, whereas the control (natural light only) was $75.8kg{\cdot}ha$. Despite of spending electricity and depreciation cost, the economic analysis showed net income with supplemental lighting after sunrise was 51% higher than control treatment in cv. spirit.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.578-586
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• 2016

In this study, we evaluated the effects of soil incorporation of crotalaria as a green manure on the growth and yields of 'Seolhyang' strawberry and inorganic soil nitrogen levels in a greenhouse. Four different N treatments were used, as follows: zero N fertilizer (control), crotalaria, crotalaria with 50% urea, and 100% urea. The recommended N requirement (100% urea) for strawberry was $86kgN{\cdot}ha^{-1}$ and 50% of the recommended N (50% urea) was $43kgN{\cdot}ha^{-1}$. Crotalaria was sowed on June $17^{th}$, 2011 and cultivated for 37 days. The amount of N supply from soil incorporation of crotalaria was $104kgN{\cdot}ha^{-1}$. Strawberry was planted on September $9^{th}$, 2011 and cultivated for 255 days after planting. The concentrations of soluble solids and acidity of strawberry fruits for the crotalaria treatment were higher than for the crotalaria with 50% urea and 100% urea treatments. On the other hand, the growth and yield of strawberry was the highest for the crotalaria with 50% urea and 100% urea treatments, followed by the crotalaria treatment, and the lowest for the control. Soil inorganic N concentration for the crotalaria treatment was continuously decreased to $24mg{\cdot}kg^{-1}$ at the end of the growing season, while crotalaria with 50% urea and 100% urea treatments maintained an inorganic N concentration that ranged from 35 to $50mg{\cdot}kg^{-1}$. These results indicate that the amount of N supply from soil incorporation of crotalaria may not be enough because strawberry yield was lower than for other N treatments. Therefore, additional nitrogen, such as 50% urea after soil incorporation of crotalaria, is recommended.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.596-606
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• 2016

The growth and contents of anthocyanins and ascorbic acid in lettuce(Lactuca sativa L., 'Jeokchima') as affected by supplemental UV-A LED irradiation under different light quality and photoperiod conditions were analyzed in this study. Five light qualities, namely B (blue LED), R (red LED), BUV (blue LED+UV-A LED), RUV (red LED+UV-A LED) and Control (white fluorescent lamps) with photoperiods of 12/12 hours (day/night), 16/8 hours, or 20/4 hours were provided to investigate the effects of light quality and photoperiod on the growth and accumulation of anthocyanins and ascorbic acid in lettuce leaves. As measured 28 days after transplanting, the number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce were significantly affected by light quality and photoperiod. The number of leaves, leaf length, leaf width, leaf area, shoot fresh weight and dry weight of lettuce grown under R treatment increased with increasing light period. By contrast, leaf development was inhibited, but chlorophyll content increased, under B treatment. Supplemental UV-A irradiation significantly decreased leaf length, leaf width, leaf area and shoot fresh weight. Anthocyanins in lettuce increased significantly with decreasing dark period under B treatment. A synergistic effect of supplemental UV-A LED irradiation on anthocyanins accumulation was found for lettuce leaves grown under R treatment but not B treatment. Ascorbic acid in lettuce was greatly affected by photoperiod. Ascorbic acid content at BUV and RUV treatments increased by 20-30% compared to without UV-A LED irradiation. From these results, it was concluded that growth and contents of anthocyanins and ascorbic acid in lettuce are significantly affected by supplemental UV-A LED irradiation. The results obtained in this study will be informative for efforts to improve the nutritional value of leafy vegetables grown in plant factories.