• Food Science and Preservation
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• v.6 no.4
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• pp.376-379
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• 1999

In an attempt to test the storage life of late maturing-medium grapes, Sheridan, Tano Red and Muscat Bailey A cultivated widely in Korea, were selected as test samples. These grapes were treated with SO2 gas and packed with polyethylene film, then stored at 0$^{\circ}C$ under 90% RH. Total weight decreased with the storage days and the loss extent of Sheridan was the least. Abnormal grapes increased along with the storage days and occurred rapidly after 90% days. After 135 days, these were produced as the following order. Sheridan < Muscat Bailey A < Tano Red. The external appearances were deteriorated with the storage days. After 135 days, these indices of Sheridan, Muscat Bailey A and Tano Red wen 6.3, 5.0 and 1.7, respectively, showing the most satisfactory result from Sheridn. Water content decreased along with the storage days. The soluble solids content and the proportionality of sugar to acids increased with the storage days, however the titratable acidity decreased. Considering these results, the storage lifes were excellent by the order Sheridan, Muscat Bailey A and Tano Red.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.89-95
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• 2019

BACKGROUND: Liquid pig manure (LPM) has been used as an alternative for conventional fertilizers on some gramineous crops. However, its chemical properties varied widely depending on the degree of the digestion. A pot experiment was conducted to determine the responses of persimmon trees to immature (not well-digested) LPM application. METHODS AND RESULTS: Ten application levels of immature LPM, consisted of a total of 3 to 30 L in 3-L increment, were applied during summer to 5-year-old 'Fuyu' trees grown in 50-L pots. Increasing the LPM application rate caused defoliation, wilting, and chlorosis in leaves. When applied with the rate of 3 L during summer, the tree produced small fruits with low soluble solids and bore few flower buds the following season, indicating insufficient nutritional status. In trees applied with the LPM rates of 6~12 L, both fruit characteristics and above-ground growth of the trees appeared normal but some roots were injured. However, application of higher LPM rates than 27 L resulted in small size, poor coloration, or flesh softening of the fruits the current season. Furthermore, the high LPM rates caused severe cold injury in shoots during winter and weak shoot growth the following season. It was noted that the application of higher LPM rate than 9 L damaged the root, even though above-ground parts of the tree appeared to grow normally. CONCLUSION: The results indicated that an excessive immature LPM application could cause various injuries on leaves, fruits, and the roots in both the current and the following season.

• Journal of the Korean Society of Food Culture
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• v.36 no.1
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• pp.84-91
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• 2021

The oriental plum (Prunus salicina) is one of the most popular fruits in Korea due to its sweet taste and pleasant aroma. The objective of this study was to analyze the quality characteristics and antioxidant activities of a puree made using plums stored at low-temperatures. The quality characteristics were determined by estimating total soluble solids (TSS, °Brix), titratable acidity (TA, % citric acid), TSS/TA ratio, pH, colors, sugar content, and sensory profiles. The antioxidant effects were estimated by total polyphenol and flavonoid content and radical scavenging activity. The results showed that the plum puree containing both the flesh and the peel had markedly higher red coloration (a⁎ value) than the puree without the peel, while yellow coloration (b⁎ value) and lightness (L⁎ value) were lower in the puree without the peel than with the peel. The sensory qualities including the plum taste and flavor, texture as well as overall acceptance showed no significant variation between the samples. Meanwhile, the total polyphenol/flavonoid content and radical scavenging activities were significantly improved by the presence of fruit peel and by frozen storage. These findings suggest that frozen plums could be a suitable ingredient for making a puree and concentrate for the food manufacturing industry.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.297-310
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• 2023

M.7 rootstock is moderately resistant to fire blight. However, M.7 is generally too vigorous for high-density apple systems, but it can be grafted onto cultivars that exhibit weak tree growth, such as 'Sansa'. This study investigated the vegetative growth, yield, and fruit quality of 'Sansa' apple trees grafted on M.7 or M.9 rootstocks to assess the feasibility of establishing domestic high-density apple systems using M.7 and to determine the optimum exposure length for rootstocks. Trees were planted with exposed rootstock lengths of 5, 10, and 15 cm. The vegetative growth of apple trees grafted onto M.7 was greater than that of M.9 and vegetative growth tended to decrease as the exposed length of rootstock increased. However, the differences in yield per tree, average weights, soluble solids contents, and titratable acidity due to the rootstock and its exposure length varied. The accumulated yield over a 10 year period and the yield efficiency of M.7 were lower than that of M.9 and the yield efficiency tended to decrease as the exposed length of rootstock increased. When apple trees were grafted onto M.9, biennial bearing and tree vigor weakening occurred if the exposed length of the rootstock was over 10 cm. Conversely, when apple trees were grafted onto M.7, vegetative growth was excessive if the exposed length of rootstock was below 10 cm. Based on the results from this study, the optimum M.7 and M.9 exposure lengths for 'Sansa' were 15 cm and 5 cm, respectively.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.282-288
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• 2013

This study was conducted to investigate the quality characteristics of eight everbearing strawberry cultivars and the effect of precooling treatment to maintain the quality during storage and shelf life of 'Charlotte'. Several quality parameters including firmness, soluble solids content (SSC), color, soluble sugars, and organic acids were evaluated. For Successful marketing everbearing strawberries required more than 1 N of firmness and $6^{\circ}Brix$ of SSC, respectively. 'Albion', 'Charlotte', and 'Goha' cultivars were higher in fruit SSC and 'Charlotte' cultivar was higher in fruit firmness among eight cultivars examined in this study. Fruit had more bright red color in 'Charlotte', 'Flamingo', 'GW-4', and 'San Andreas', which may reflect the consumer acceptance. Physicochemical characteristics of 'Charlotte' strawberry after with/without room precooling treatment were evaluated during storage at $4^{\circ}C$, $10^{\circ}C$, and $25^{\circ}C$ and additional 3 days at $25^{\circ}C$ for shelf-life. Weight loss increased about 8% in the fruits stored at $25^{\circ}C$ for 3 days, while in low temperature storage was about 2% for 7 days showing precooling was more effect on during shelf life periods rather than storage periods. Decay was not found during storage at $4^{\circ}C$ regardless of precooling treatment, but fungal growth was found in all the treatments after transferred to room temperature. Precooling treatment did not affect fruit color in shelf life period. For advanced marketing, everbearing strawberry should maintain in low temperature less than $4^{\circ}C$ to sustain quality, but the room precooling showed less significant effect to maintain quality on 'Charlotte' cultivar.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.80-85
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• 2018

This study was carried out to clarify the effect of CHO-CO and PO film on air temperature in greenhouse and Korean melon fruit characteristics and yield. On January 8 in 2017, the maximum, minimum and average air temperature in greenhouse covered with CHO-CO film were $38.9^{\circ}C$, $13.4^{\circ}C$ and $20.1^{\circ}C$, respectively. At the same date, the maximum, minimum and average air temperature in greenhouse covered with PO film were $40.0^{\circ}C$, $14.9^{\circ}C$ and $20.3^{\circ}C$, respectively. On August 7 in 2017, the maximum, minimum and average air temperature in greenhouse covered with CHO-CO film were $47.2^{\circ}C$, $23.1^{\circ}C$ and $32.4^{\circ}C$, respectively, and the maximum, minimum and average air temperature in greenhouse covered with PO film were $50.3^{\circ}C$, $23.6^{\circ}C$ and $34.0^{\circ}C$, respectively. The results of investigation of qualities and yields of Korean melons from May 26 to August 15 in 2017 were as follows. The fruit weight of Korean melon harvested in CHO-CO film's greenhouse was 371.6g which was 22.2g less than that of PO film greenhouse. The sugar contents of Korean melon harvested in CHO-CO film greenhouse was $14.5^{\circ}brix$ which was $1.4^{\circ}brix$ greater than that of the fruits harvested in PO film greenhouse. The chromaticity (a-value) of fruit skin of Korean melon harvested in CHO-CO film greenhouse was 12.3 which was 1.5 greater than that of the fruits harvested in PO film greenhouse. The marketable yield rate of Korean melon harvested in CHO-CO film's greenhouse was 89.4% which was 8.0% higher than the fruits harvested in PO film greenhouse. The yield of Korean melon harvested in CHO-CO film's greenhouse was 2694kg per 10 a which was 26% more than that harvested in PO film greenhouse. In conclusion, the CHO-CO film could be effective to produce Korean melon in high temperature season.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.166-170
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• 2013

BACKGROUND: Persimmon growers have often tried various regimens of K fertilization to improve fruit quality. This experiment was conducted to determine the effects of K rates on concentration of inorganic elements in different tree organs and on fruit characteristics. METHODS AND RESULTS: Six-year-old non-astringent 'Fuyu' persimmons, grown in 50-L pots, were used. Total K amounts of 0 (no-application), 12, 25, 37, and 66 g were fertigated to a pot with KCl solution at 3-to 4-day intervals from July to September. The 0 K trees received no K fertilizer for the two previous years. Leaves, fruits, and shoots were sampled in November. K concentrations in leaves and shoots increased significantly by increasing K rate; leaf K, 0.49% for the 0 K, increased to 3.09% for the 37 g and 3.11% for the 66 g trees. Fruit K was notably lower for the 0 K, but there were no significant differences among the trees as long as they were supplied with more than 12-g K. In the trees with 0 K, leaf necrosis in the margin was apparent in June and the symptom progressed toward the midrib. Some leaves scorch-rolled from the margin in August. The greatest effect of K rates was on fruit size; it significantly increased to 181 g for the 12 g, 203 g for the 37 g, and 206 g for the 66 g compared with 150 g for the 0 K trees. However, K rates did not affect firmness and soluble solids of the fruits. The fruits of the 0 K trees were characterized by better coloration. CONCLUSION(S): The K-rate effect on inorganic elements depended on tree organs and fruit size was the major parameter to be affected by the K rates.

• Food Science and Preservation
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• v.21 no.3
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• pp.365-372
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• 2014

Imported Valencia oranges were evaluated to determine the relationship between the fruit size and its quality. The orange size was classified into three groups on a commercial basis: small ($140{\sim}160g/113{\pm}5$ fruit/box), medium ($190{\sim}220g/88{\pm}5$ fruit/box), and large ($250{\sim}280g/72{\pm}5$ fruit/box). The physicochemical and sensory properties were analyzed to evaluate the orange quality. No significant difference in the peel thickness and flesh ratio was detected across the fruit sizes. The juice yield of the medium-sized orange and the TSS/TA ratios of the medium-sized and large oranges showed the highest value, respectively (p<0.05). The large orange had the highest vitamin C content, which was positively correlated with both its DPPH and ABTS radical scavenging abilities (p<0.05). In the sensory evaluation of the fruits and their juice, the scores for sourness and overall preference were significantly higher in the medium-sized and large oranges than in the small ones. The total soluble solids, total acidity, TSS/TA ratio, and reducing sugar content were significantly related to the sensory properties. Finally, the quality and sensory properties were considered superior in the medium-sized and lager Valencia oranges. Further studies on the effects of the variety and origin of Valencia oranges on their quality and sensory properties are required.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.812-818
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• 2014

Raising seedlings is important for fruit crops and is especially significant for strawberries as it accounts for 80% of their cultivation. However, there are few studies on raising seedlings of strawberries by hydroponics. Since strawberries show clear differences in growth characteristics based on cultivar, it is necessary to develop suitable fertilizer formula, concentration and pH for each cultivar, and also to examine the amount of nutrient feeding appropriate for each medium type. A key to raising seedlings of strawberries by hydroponics is the development of strategies to manage the concentration of nutrient solution. The mother plants of 'Daewang' strawberries were planted on hydroponics benches filled with cocopeat on March 28, 2012. Three nutrient solution treatments were employed during the term of raising seedlings: a type that supplied EC $0.6dS{\cdot}m^{-1}$ nutrient solution for 30 days and only water for 20 days [0.6 (30) + 20]; a type that supplied EC $1.2dS{\cdot}m^{-1}$ nutrient solution for 30 days and only water for 20 days [1.2 (30) + 20]; and a type that supplied EC $1.2dS{\cdot}m^{-1}$ nutrient solution for 50 days [1.2 (50)]. The plants were then planted on hydroponics benches filled with cocopeat on September 20, and managed with EC $0.6-0.8dS{\cdot}m^{-1}$ strawberry nutrient solution developed by Yamazaki. After planting, shoot growth, flowering rate and fruit quality of the first cluster were investigated. The petiole length, leaf length, leaf width and crown diameter showed the highest grown in the [1.2 (50)] treatment, followed by [1.2 (30) + 20], and then [0.6 (30) + 20], indicating that the higher concentration of nutrient solution was preferable for raising seedlings. However, the growth differences among treatments gradually disappeared as growth continued, and the crown diameter especially grew to exhibit almost no difference at all among treatments. The point of flowering came first in [0.6 (30) + 20], followed by [1.2 (30) + 20] and then [1.2 (50)]. The [0.6 (30) + 20] treatment showed much earlier flowering than other treatments, which implies that low-concentration nutrient solution may be beneficial to the flowering of 'Daewang' strawberries while raising seedlings. There was no statistically significant difference among treatments in fruit length, fruit diameter and fruit firmness. Fruit weight in [1.2 (50)] treatment was significantly higher than other treatments. However, soluble solids of fruit was the lowest in [1.2 (50)] treatment. Together, the results of this experiment imply that it is better to supply EC $0.6dS{\cdot}m^{-1}$ solution for 30 days and then supply only water for 20 days to adequately manage concentration of nutrient solutions during the period of raising seedlings of strawberries by hydroponics.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.289-295
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• 2014

This research was conducted to investigate a difference in quality according to control of fruit load and cluster weight when seeded 'Heukboseok' grape was grown in a conventional cultivation system. Clusters per vine were set to harvest 1,500 kg, 1,800 kg, and 2,200 kg grapes per $990m^2$. In p lots t reated t o produce 1,800 kg grapes, clusters were set to 3 grades produce grapes with 350 g, 500 g, and 700 g in cluster weight. Based on color chart (National Institute of Horticultural & Herbal Science, Rural Development Admnistration) which show maturation stage for 'Kyoho' grape, grapes with higher than grade 9 were harvested at 80 and 90 days after full bloom, and the r est of them were harvested a t 100 days after full bloom. The final yield of 'Heukboseok' grape was the lowest in target yield of 1,800 kg with 700 g clusters with 75.5% of target yield, but 92.1%-100.1% of target yield were harvested in other treatments. Among treatments with several fruit setting, 83.3% of grapes harvested in treatment to produce 1,500 kg grapes as a target yield at 90 days after full bloom. Among the treatments with different cluster weights, 93.5% grapes were harvested in the treatment with 350 g in cluster weight. 'Heukboseok' grape showed rapid maturation pattern with no significant difference in either soluble solids content or acidity between 90 days from 80 days after full bloom. Therefore, to prevent flesh softening, it is appropriate to harvest fruit at 90 days after full blooms, and both yield and cluster weight were important factors influencing the quality of the fruits in 'Heukboseok' grape. It is confirmed that coloring and firmness was influenced by the final yield and weight per cluster, respectively. Therefore, the yield should be set as grape of 1,500 kg per $990m^2$ in target yield, and cluster weight should be adjusted to 350 g to produce grape of 1,800 kg with the fruits of high quality. It is considered to be hard to produce grape of high quality with 700 g in cluster weight in 'Heukboseok' grape.