• Korean journal of applied entomology
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• v.31 no.2
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.225-234
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• 2009

The aim of this study was to analyze moisture, crude protein, crude lipid, vitamin C and sugar changes in selected Korean chestnut cultivars such as Danteack, Deabo, Seokchu, Okkwang and Byunggo during storage at $4^{\circ}C$ and $-10^{\circ}C$ for 10 months. The moisture contents of selected Korean chestnut cultivars ranged from 49.9 to 57.4%. The moisture content of Seokchu was the highest. The contents of moisture in white kernel were higher than that in yellow kernel. The content of moisture showed decreasing tendency after 10 months of storage. The crude protein and crude lipid contents in whole kernel of selected Korean chestnut cultivars were $3.3{\sim}4.2%$ and $0.3{\sim}1.6%$, respectively. The crude protein content of Deabo was the highest. The crude protein in Danteack, Seokchu, Okkwang and Byunggo was increased during storage at $4^{\circ}C$ for 10 months, while that in whole kernel of Deabo was decreased and no changes in crude protein in yellow kernels of Deabo were observed. The crude protein in Okkwang was increased during storage at $-10^{\circ}C$ for 10 months. The cold storage was found to have higher composition change of crude protein than the freezing storage. The content of crude lipid in Daebo and Byunggo was decreased during storage at $4^{\circ}C$ and $-10^{\circ}C$. Yellow kernels of Deabo, Okkwang and Byunggo were found to have higher crude lipid content than white kernels. The vitamin C content also decreased during storage at $4^{\circ}C$ and $-10^{\circ}C$ and the decrease in vitamin C content was higher at $4^{\circ}C$ than $-10^{\circ}C$. Vitamin C was not detected after 3 months storage at $-10^{\circ}C$. The sugar content increased at the latter period storage at $4^{\circ}C$ and $-10^{\circ}C$. The sugar content of selected Korean chestnut cultivars ranged from $36.2{\sim}44.3%$ and Dantaek had the highest sugar content.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.7-14
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• 2013

This study investigated the optimum condition of abrasion peeling machine and pellicle peeling ability of chestnut (Castanea spp.) varieties for the efficient production of peeled chestnuts. The optimum conditions were 50 minutes peeling time and 27 rpm of drum rotation speed and chestnut pellicle peeling ratio was 89.3%. Among 8 Korean chestnut varieties which were peeled under the optimum condition (27 rpm/50 min), 'Tsukuba (89.3%)', 'Tanzawa (72.2%)' and 'Ishizuchi (70.9%)' showed the highest ratio of pellicle peeling ratio. 'Tsukuba' had the most excellent peeled (grade I) chestnuts (77.3%), followed by 'Ishizuchi (46.7%)', and 'Tanzawa (45.0%)'. Regarding the chestnuts quality for commercialization, 'Tsukuba' had the most excellent peeled chestnuts (90.5%), followed by 'Tanzawa (74.8%)', and 'Ishizuchi (74.3%)'. 'Mipung (37.2%)' had the most broken and injured chestnuts and 'Tsukuba (5.9%)' had the least broken and injured chestnuts. Therefore this study concluded that 'Tsukuba' was the superior variety for producing high value-added processed chestnuts.

• Korean journal of applied entomology
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• v.50 no.4
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• pp.379-382
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• 2011

The damage rates of peach pyralid moth(Dichocrocis punctiferalis), which damages the chestnut fruits, were investigated annually from 1995 to 2010 according to year, region, and maturity. The damage rate by D. punctiferalis was the highest (34.5%) in 1998 and was the lowest (17.9%) in 2000. The pattern of the damage rate showed a repeating three-year cycle. There was a negative correlation ($-0.6261^*$) between rainfall and damage rate. There was a positive correlation ($0.5826^*$) between temperature and damage rate. The average damage rate of all surveyed regions was 22.2%. Of the surveyed areas, Hapcheon had the highest at 27% and Hamyang had the lowest at 15.0%. The damage rate of chestnut fruit depending on the maturity was 26.1% in an early maturing cultivar (Dantaek), and 19.3% and 21.1% in a late maturing cultivar (Eungi) and a medium maturing cultivar (Chukpa), respectively.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.93-102
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• 2016

This research was conducted for major cultivated chestnut (Castanea spp.) in Korea to compare chestnut quality characteristics according to storage temperatures ($4^{\circ}C$ vs. $-1^{\circ}C$) and cultivars. Color, hardness, soluble solids content (SSC), rate of decay and sensory evaluation were investigated during 16 weeks storage. Cultivars 'Tsukuba' and 'Ishizuchi' showed the least pericarp color change while cultivars 'Riheiguri' and 'Daebo' showed the most pericarp color change during storage. Chestnut fruits stored at $-1^{\circ}C$ showed less pericarp color change than those stored at $4^{\circ}C$. Cultivars 'Arima' and 'Tanzawa' exhibited the decrease tendency of hardness with lowest hardness during storage at $-1^{\circ}C$. Chestnut fruits stored at $4^{\circ}C$ showed high hardness than those stored at $-1^{\circ}C$. Cultivars 'Riheiguri' showed the highest increase of SSC, while cultivar 'Arima' showed the lowest increase of SSC after 16 weeks of storage. The SSC increased in nuts from all cultivars at both temperatures, but nuts stored at $-1^{\circ}C$ showed higher increases in SSC than nuts stored at $4^{\circ}C$. Cultivars 'Ishizuchi' and 'Riheiguri' showed high rates of decayed nuts in contrast to cultivars 'Daebo', 'Okkwang' and 'Tanzawa' that showed low rates of decayed nuts during storage. The chestnut fruit stored at $-1^{\circ}C$ showed less decay than fruit stored at $4^{\circ}C$. Texture and sweetness were tested for sensory evaluation. Among the tested cultivars, 'Riheiguri', 'Daebo' and 'Tsukuba' showed hard texture and very sweetness, while 'Tanzawa' showed relatively soft texture. 'Arima' and 'Okkwang' showed weak sweetness during storage. Nuts stored at $4^{\circ}C$ exhibited harder texture than nuts stored at $-1^{\circ}C$ while $-1^{\circ}C$ exhibited more sweetness than nuts stored at $4^{\circ}C$. Chestnuts for hard texture and short-term storage (less than one month), $4^{\circ}C$ will be a proper storage temperature, while in order to store long-term (more than 4 month), $-1^{\circ}C$ will be a proper storage temperature. Result from this study provide base-line data of postharvest management for Korean cultivated chestnut as well as contributing increased product value and income for chestnut producers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1095-1100
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• 2008

Antioxidative and macrophage phagocytic activities and contents of functional component in selected Korean chestnuts (Dantaek, Daebo, Okkwang, Seokchu, Byunggo) were evaluated. Coumarin, gallic acid and catechin in inner skin and whole kernel of selected Korean chestnuts were detected by HPLC. The predominant functional components in inner skin of chestnut were catechin, followed by gallic acid and coumarin. However, the whole kernel had only gallic acid. Thus, the antioxidant properties of gallic acid and catechin were evaluated through DPPH radical-scavenging activity and SOD like activity. Gallic acid and catechin at 6.0 mg/100 g exhibited 69.4% and 38.3% of scavenging activities on DPPH radical, respectively. DPPH radical-scavenging activity of gallic acid increased in a concentration-dependent manner. Gallic acid was found to possess higher DPPH radical-scavenging activity than equivalent amount of catechin at all concentrations, whereas catechin was found to have higher SOD like activity than gallic acid. In addition, pre-incubation of macrophage with white kernel extract from Byunggo resulted in a significant increase of phagocytic activity and yellow kernel extracts from Byunggo, Dantaek, Daebo and Okkwang, leading to an increase in phagocytic activity compared with untreated cells. Yellow kernel extracts was found to have higher phagocytic activity than white kernel extracts. Byunggo had the highest phagocytic activity. The results suggest that the Korean chestnut may provide a natural source of antioxidants and active immunity.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.616-622
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• 2011

This study was conducted to investigate the effects of region and age on nut quality of major chestnut cultivars (Castanea spp.) cultivated in the central region of Korea to provide basic data for nut quality control and processing of postharvest. In the survey of by regions and ages, Buyeo and 'Hyogo57' showed the highest value by regions and cultivars, respectively. Also, there were statistically significant differences among regions and cultivars in the value of soluble solid content and kernel hardness. In the soluble solid content, Gongju showed the highest value among regions, and 'Tsukuba' among cultivars was the highest, 20.5%. Cheongyang showed the highest value of kernel hardness among regions, and 'Tanzawa' among cultivars showed the lowest value of kernel hardness, $8.75kg/cm^2$. In 'Tanzawa', 'Okkwang' and 'Tsukuba', soluble solid content and kernel hardness showed statistically significant differences according to age, but no correlation with age.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.95-100
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• 2009

This study was conducted to develop environmentally friendly control techniques to reduce chestnut insect pests. The study sites were selected in intensive chestnut orchards of Jinju city, Gyeongnam province. In early and middle-ripening cultivars of chestnut tree, the damage of chestnut fruits by Dichocrocis punctiferalis was significantly lower in wromstop than other treatment such as wromstop+wood vinegar, Capture-machine (p<0.05), While there was no significant difference among treatments in late-ripening cultivars. The hight control effect for D. punctiferalis was showed the highest in wromstop treanment with 40.49% and 41.89% in early and late-ripening cultivars. The control effects for Curculio sikkimensis in late-ripening cultivars of chestnut tree were 34.59% in wromstop imidacloprid treatment and 28.94% in air control treatment.

• Journal of Korean Society of Forest Science
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• v.26 no.1
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• pp.19-22
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• 1975

Freezing resistance of ten cultivars of Chestnut (Castanea crenata S. et Z.) collected from four different sites of Kyunggi Province, Korea on March 2, 1975, was measured to find out the differences among tissue parts, and those among cultivars. The freezing and thawing rates were controlled lower than $6^{\circ}C/hr$. which occurs in nature. The resistance to low temperature was in order from lowest to highest; winter bud, cambium, xylum ray parenchyma and bark cortex. The difference in cold hardiness among cultivars was not consistent among tissue parts of twig stem except in cultivar Dan-Taeck of which all tissue parts showed highest cold-hardiness. The importance of the study on the seasonal variation in cold hardiness of different tissue parts was discussed in terms of choosing the most cold resistant Chestnut culitivar in Korea.

• Journal of the Korean Wood Science and Technology
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• v.38 no.6
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• pp.490-497
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• 2010

Radial variations in the lengths of wood fibers and vessel elements in the stem of chestnut (Castanea crenata) grown in Korea were investigated to get some fundamental information for efficient use of wood. Seven chestnut cultivars (Tanzawa, Ibuki, Arima, Ginyose, Tsukuba, Riheiguri, and Mansung) were examined in this study. The lengths of wood fibers and vessel elements were measured and analyzed by an optical microscope and an imaging analysis system. In all chestnut cultivars, the wood fiber length of latewood was longer than that of earlywood, and increased with the increase of growth ring number. Similarly, vessel element length of latewood was longer than that of earlywood, and showed increasing tendency with the increase of growth ring number. Consequently, it was considered that the lengths of wood fibers and vessel elements could be used for separating juvenile wood from adult wood in the chestnut stem.