• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.133-137
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• 1982

An experiment was conducted to find out the proper and effective fumigation method for harvested fresh chestnuts produced in Korea. Fumigation with phosphine, causing damages on chestnuts by rapid corruption or change in color on pericarp, did not completely kill chestnut curculio and nut fruit tortrix larvae in harvested fresh chestnuts regardless of long exposure of chestnuts to phosphine. Any damages not being appeared by fumigant, fumigation with methyl bromide at $40g/m^3$ for 4 hours at $21^{\circ}C$ would retain the low control against inclusion of any chestnut pests tested. Though fumigation with methyl bromide at $50g/m^3$ for 24hours was effective against any larvae of chestnut insects control, they caused serious damages by making the flesh surface of harvested fresh chests dark or dense brown. However, fumigation with methyl bromide at $50g/m^3$ for 4 hours at $21^{\circ}C$ resulted in complete kill of larvae of Curculio dentipes and Carpocapsa splendana in harvested fresh chestnuts with no significant damages on the treated fruits.

• 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.

• Food Science and Preservation
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• v.8 no.1
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• pp.16-22
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• 2001

The study was performed to investigate the effects of delayed gamma-irradiation and CA storage on the keeping quality of chestnuts. Chestnuts peviously stored for 3 months at 0$^{\circ}C$ were irradiated at 0 to 0.25 kGy of Co$\^$60/ gamma rays and then stored for 6 months under CA conditions of 3% O$_2$ and 5% CO$_2$ or air at 0$^{\circ}C$. Delayed gamma-irradiation completely inhibited the sprouting of chestnuts, and tore reduced the rotting rate by the combination with CA storage. The weight loss was reduced by delayed gamma-irradiation and CA storage. Hunter L and b values of flesh surface of the chestnuts stored under CA were higher than those of samples stored under air regardless of gamma irradiation. Vitamin C, total sugar and reducing sugar contents decreased immediately after irradiation Vitamin C and reducing sugar contents after 6 months of storage were lower in the samples kept under CA than in those under air. Results indicated that delayed gamma-irradiation after harvest and subsequent CA storage showed inhibitory effects against the development of saluting and rotting and the loss of weights and surface flesh color changes in chestnuts.

• Journal of Biosystems Engineering
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• v.33 no.1
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• pp.21-29
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• 2008

In this study, the thermal properties of peeled chestnuts were measured, and the mathematical prediction model of freezing time was also developed for various interior positions from center to rind (surface). The measured thermal properties were showed that heat conductivity is $0.43W/m^{\circ}C$, specific heat is $2.7206J/m^3^{\circ}C$, latent heat is $216.9{\times}10^6J/m^3$ and freezing point is $-2.8^{\circ}C$. The entire process about reaching to the freezing time of peeled chestnuts was analyzed with its each regular depth position using the finite difference method (FDM) based on computer simulation. In case of regular freezing temperature, it was showed an that surface (rind) position is more rapidly reached into the freezing point rather than the center position, and also reaching time to the freezing point is more fast at the lower freezing temperature. Comparison results between simulation and experiments showed linear relationship. In regularly varying condition for freezing temperature, this method would give an information to predict a freezing time of the interior points for peeled chestnuts and more similar agricultural products.

• Journal of Nutrition and Health
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• v.49 no.5
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• pp.395-399
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• 2016

Purpose: Gongju is a famous area for chestnuts, which contain various nutrients and phytochemicals. This study aimed to develop gochujang items using Gongju chestnuts and analyze nutritional properties for the best item by sensory evaluation in order to increase marketability of chestnut processed foods. Methods: Gochujang was prepared, and nutrient contents of gochujang were analyzed according to the methods of the food fair by Korea Food Research Institute. Three kinds of gochujang, including general (control)-, dried chestnut powder-, and chestnut syrup- were prepared. Sensory evaluation was performed on three kinds of gochujang by 45 adults, including males and females (20's~60's years of age). Results: Chestnut syrup-gochujang was evaluated as significantly higher than general- or dried chestnut powder-gochujang by sensory evaluation. Thus, nutrition facts were produced for chestnut syrup gochujang. Nutrient contents per 100 g of chestnut syrup gochujang and traditional gochujang in the literature were similar in terms of total carbohydrates and fat, whereas protein content was higher and sodium content was lower in chestnut syrup gochujang than in traditional gochujang in the literature. Conclusions: The results imply that chestnut syrup gochujang has nutritional benefits such as higher content of protein and lower content of sodium than traditional gochujang in the literature, in addition with its good taste. Therefore, chestnut syrup gochujang may have high usage potential. There is a need to improve the quality and storage of chestnut syrup gochujang through future study.

• The Korean Journal of Food And Nutrition
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• v.22 no.4
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• pp.587-597
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• 2009

Peeled chestnuts were stored at different temperatures($-10^{\circ}C$ and $-20^{\circ}C$) and after blanching at $90^{\circ}C$ for different lengths of time(0, 10, and 20 min) for 6 months. After the storage period, the texture, color, DSC and sensory characteristics were analyzed. Hardness, fracturability and chewiness increased with storage time, whereas springiness and cohesiveness decreased. Additionally, the L* decreased and a* and b* increased with storage time. Analysis of the DSC revealed that the peak of the retro gradation was approximately $46{\sim}60^{\circ}C$ and enthalpy for the peak increased with storage time. Additionally, the increment of enthalpy for samples stored at $-20^{\circ}C$ and blanched was lower than that of samples stored at $-10^{\circ}C$ and non-blanched samples. The sensory evaluation scores were also higher for samples stored at $-20^{\circ}C$ and blanched samples than for those stored at $10^{\circ}C$ and non-blanched samples.

• Journal of Biosystems Engineering
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• v.22 no.3
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• pp.289-294
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• 1997

The chestnut is a well-known and important forest product in Korea. The annual production of chestnut is about 100, 000tons and its cultivating area is 80, 000ha. However, the peeling process of outer and inner skins of chestnut is very difficult due to hardness and adhesiveness of chestnut skin. The peeling process of chestnut was operated by manual work and the performance of chestnut peeling machine is very low. The purpose of this study is to develope the prototype of new chestnut peeling system. The hardness of chestnuts was tested with six different drying conditions and its range was from 949$g/mm^2$ to 2, 149$g/mm^2$. The hardness of chestnuts was decresed gradually during the drying process. The chestnut peeling Process includes sorting, storage, drying, outer skin cutting, flame peeling, continuous frictional skin peeling, and inner skin cutting operation. The developed chestnut peeling system consists of outer skin cutter, flame peeler, continuous frictional skin peeler and inner skin cutter. The system can peel domestic chestnuts at 150$kg/hr$ with peeling rate of 78%.

• Applied Biological Chemistry
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• v.41 no.7
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• pp.545-549
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• 1998

This study was carried out to improve the storage stability of export peeled-chestnuts using electrolyzed acid-water, because ice-cold tap water generally used to store export peeled-chestnuts grew turbid during the cold chain, decreasing the quality. The changes of pH and turbidity in the electrolyzed water used for storing peeled-chestnuts were investigated. The pH value rapidly changed when stored at $30^{\circ}C$, whereas it very slowly changed at $4^{\circ}C$. This was especially evident by the change in pH from 2.5 to 3.4 of the electrolyzed acid-water after 8 days. In the case of turbidity, closely correlated with the pH change, the electrolyzed water used for storing peeled-chestnuts was very turbid when stored at $30^{\circ}C$, but it was not even until 14 days at $4^{\circ}C$, as evident by the absorbance $(OD_{660})$ of electrolyzed acid-water at pH 2.5 and $4^{\circ}C$ being only 0.01 after 14 days and 0.11 after 35 days. Sensory evaluation, tested by expert panel, of the chestnuts stored in electrolyzed water was not significantly different compared to the control.

• Food Science and Preservation
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• v.5 no.1
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• pp.7-12
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• 1998

Chestnuts(Castanea cretana, Eunki) were used for quality evaluations from the physiological and physicochemical points of view during storage under different temperatures and relative humidities for 8 months. Quality criteria included spouting, rotting, weight loss, and the changes in moisture, total sugar, reducing sugar, and total vitamin C of the stored sample. Sprouts(roots) were developed in about 2 months in all stored samples which had been mixed with sawdust(50% moisture) and stored under the conditions of 2∼25$^{\circ}C$ and 62∼95% RH. The sprout development was more significant in the storage temperature of Pit(9${\pm}$6$^{\circ}C$, 80${\pm}$5% RH, PT)and room(16${\pm}$7$^{\circ}C$, 85${\pm}$10% RH, RT) than low(3${\pm}$1%, 80${\pm}$5% RH, LT)and ambient(14${\pm}$11$^{\circ}C$, 67${\pm}$5% RH, AT). The rates of rotting and weight loss were appreciable in the order of PT, AT, RT and LT, and those of LT were 1∼2%. The use of wet sawdusts resulted in the increase of moisture contents in stored samples, thereby causing the rotting phenomena. Some chemical components of stored samples were found liable to the changes according to storage conditions, that is; total sugars showed a decreasing tendency along with a temporary increase during storage, and both reducing sugar and vitamin C were similarly accumulated in the samples stored at low temperature conditions. The results indicated that long-term storage of chestnuts will be possible in either cases of the application of low temperature following sprout-inhibition treatment or the use of lower temperature than 0$^{\circ}C$ to suppress its sprouting during storage.

• Journal of Biosystems Engineering
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• v.38 no.3
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• pp.185-191
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• 2013

Purpose: The present study focused on the estimation of soluble solids content (SSC) of chestnut using reflectance and transmittance spectra in range of VIS/NIR. Methods: Four species intact/peeled chestnuts were used for acquisition of spectral data. Transmittance and reflectance spectra were used to develop the best PLS model to estimate SSC of chestnut. Results: The model developed with the transmitted energy spectra of peeled chestnuts rather than intact chestnuts and with range of NIR rather than VIS performed better. The best $R^2$ and RMSEP of cross validation were represented as 0.54 and $1.85^{\circ}Brix$. The results presented that the reflectance spectra of peeled chestnuts by species showed the best performance to predict SSC of chestnut. $R^2$ and RMSEP were 0.55 and $1.67^{\circ}Brix$. Conclusions: All developed models showed RMSEP around $1.44{\sim}2.54^{\circ}Brix$, which is considered not enough to estimate SSC accurately. It was noted that $R^2$ of cross validation that we found were not high. For all that, grading of the fruits in two or three classes of SSC during postharvest handling seems possible with an inexpensive spectrophotometer. Furthermore, the development of estimation of SSC by each chestnut species could be considered in that SSC distribution is clustering in different range by species.