• Journal of Biosystems Engineering
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• v.4 no.2
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• pp.65-83
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• 1979

Low-temperature drying systems have been extensively used for drying cereal grain such as shelled corn and wheat. Since the 1973 energy crisis, many researches have been conducted to apply solar energy as supplemental heat to natural air drying systems. However, little research on rough rice drying has been done in this area, especially very little in Korea. In designing a solar drying system, quality loss, airflow requirements, temperature rise of drying air, fan power and energy requirements should be throughly studied. The factors affecting solar drying systems are airflow rate, initial moisture content, the amount of heat added to drying air, fan operation method and the weather conditions. The major objectives of this study were to analyze the effects of the performance factors and determine design parameters such as airflow requirements, optimum bed depth, optimum temperature rise of drying air, fan operation method and collector size. Three hourly observations based on the 4-year weather data in Chuncheon area were used to simulate rough rice drying. The results can be summarized as follows: 1. The results of the statistical analysis indicated that the experimental and predicted values of the temperature rise of the air passing through the collector agreed well. 2. Equilibrium moisture content was affected a little by airflow rate, but affected mainly by the amount of heat added, to drying air. Equilibrium moisture content ranged from 12.2 to 13.2 percent wet basis for the continuous fan operation, from 10.4 to 11.7 percent wet basis for the intermittent fan operation respectively, in range of 1. 6 to 5. 9 degrees Centigrade average temperature rise of drying air. 3. Average moisture content when top layer was dried to 15 percent wet basis ranged from 13.1 to 13.9 percent wet basis for the continuous fan operation, from 11.9 to 13.4 percent wet basis for the intermittent fan operation respectively, in the range of 1.6 to 5.9 degrees Centigrade average temperature rise of drying air and 18 to 24 percent wet basis initial moisture content. The results indicated that grain was overdried with the intermittent fan operation in any range of temperature rise of drying air. Therefore, the continuous fan operation is usually more effective than the intermittent fan operation considering the overdrying. 4. For the continuous fan operation, the average temperature rise of drying air may be limited to 2.2 to 3. 3 degrees Centigrade considering safe storage moisture level of 13.5 to 14 perceut wet basis. 5. Required drying time decrease ranged from 40 to 50 percent each time the airflow rate was doubled and from 3.9 to 4.3 percent approximately for each one degrees Centigrade in average temperature rise of drying air regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on required drying time. 6. Required drying time increase ranged from 18 to 30 percent approximately for each 2 percent increase in initial moisture content regardless of the fan operation methods, in the range of 18 to 24 percent moisture. 7. The intermittent fan operation showed about 36 to 42 percent decrease in required drying time as compared with the continuous fan operation. 8. Drymatter loss decrease ranged from 34 to 46 percent each time the airflow rate was doubled and from 2 to 3 percent approximately for each one degrees Centigrade in average temperature rise of drying air, regardless of the fan operation methods. Therefore, the average temperature rise of drying air had a little effect on drymatter loss. 9. Drymatter loss increase ranged from 50 to 78 percent approximately for each 2 percent increase in initial moisture content, in the range of 18 to 24 percent moisture. 10. The intermittent fan operation: showed about 40 to 50 percent increase in drymatter loss as compared with the continuous fan operation and the increasing rate was higher at high level of initial moisture and average temperature rise. 11. Year-to-year weather conditions had a little effect on required drying time and drymatter loss. 12. The equations for estimating time required to dry top layer to 16 and 1536 wet basis and drymatter loss were derived as functions of the performance factors. by the least square method. 13. Minimum airflow rates based on 0.5 percent drymatter loss were estimated. Minimum airflow rates for the intermittent fan operation were approximately 1.5 to 1.8 times as much as compared with the continuous fan operation, but a few differences among year-to-year. 14. Required fan horsepower and energy for the intermittent fan operation were 3. 7 and 1. 5 times respectively as much as compared with the continuous fan operation. 15. The continuous fan operation may be more effective than the intermittent fan operation considering overdrying, fan horsepower requirements, and energy use. 16. A method for estimating the required collection area of flat-plate solar collector using average temperature rise and airflow rate was presented.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1115-1119
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• 1999

Chitosan was used to treat lavers during the production of dried lavers. In the procedure of washing the harvested lavers, the lavers were treated with various solutions of 0.1 and 0.01% of 30 cp chitosan and of 0.005 and 0.04% of 90 cp chitosan. Then treated lavers were processed as usual for the production of dried lavers. Significant differences between chitosan-treated and non-treated lavers were observed in flavor, in total microbial counts, and in the number of coliform microorganisms. Off-flavor of dried lavers was reduced significantly by treating with chitosan. Total microbial count was $3.7{\times}10^{4}$ cells/g in the non-treated dried lavers, but they were $5.7{\times}10^{3}$ cells/g and $2.1{\times}10^{3}$ cells/g, respectively, in the dried lavers treated with 0.01% and 0.1% of 30 cp chitosan. The number of coliform microorganisms was 240 cells/g in non-treated dried lavers. However, coliform microorganisms were not detected in the dried lavers treated with 0.1% of 30 cp chitosan. When the dried lavers were used to make Kimbab (rice rolled with laver), the number of total microorganisms increased very slowly during storage time at $20^{\circ}C$ in the Kimbab rolled with chitosan-treated dried lavers compared to that in the Kimbab rolled with non-treated dried lavers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.61-67
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• 2017

Chia seed (Salvia hispanica L.) originated from Central America is a highly nutritious food containing large amounts of linolenic acid, dietary fiber, and protein. This study investigated the quality properties and antioxidant activities of Sulgidduk prepared with chia seed powder as a functional material. Freeze-dried chia seed powder was replaced with 0, 1, 3, 5, and 7% of rice flour. The addition of chia seed powder did not affect water content, whereas the pH value of the chia seed group decreased as compared to the control. For color measurements, a and b values increased as the amount of chia seed powder increased, whereas L value decreased. Hardness and chewiness of Sulgidduk with chia seed powder were lower than those of the control, whereas springiness of the chia seed group was higher than that of the control. Cohesiveness was not significantly different in all samples. According to retrogradation analysis based on changes in hardness during storage, it was confirmed that addition of chia seed powder inhibited aging of Sulgidduk. Retrogradation of CSP5 was the slowest. Consumer acceptability analysis did not show significant differences in all samples. Total polyphenol and flavonoid contents tended to significantly increase as chia seed content increased. DPPH and ABTS radical scavenging activities of Sulgidduk were also elevated due to addition of chia seeds. From the results, addition of chia seed softened texture, inhibited aging, and enhanced antioxidant activities of Sulgidduk. It is concluded that addition of 5% chia seed powder, which showed high effectiveness for aging, is the most suitable for commercialization.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.2
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• pp.11-18
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• 2018

Biochar is a carbon-rich solid product obtained by the pyrolysis of biomass. It has been suggested to mitigate climate change through increased carbon storage and reduction of greenhouse gas emission. The objective of this study was to evaluate carbon dioxide ($CO_2$) and nitrous oxide ($N_2O$) emissions from soil after various biochars addition. The biochars were produced by pyrolysing pear branch, rice hull and bean straw at $400{\sim}500^{\circ}C$. The treatments were consisted of a control without input of biochar and three type biochars input as 5.0 Mg/ha. Emissions of $CO_2$ and $N_2O$ from upland soil were determined using closed chamber for 8 weeks at $25^{\circ}C$ of incubation temperature. It was shown that the cumulative $CO_2$ were 207.1 to $255.2g\;CO_2/m^2$ for biochar input treatments and $258.6g\;CO_2/m^2$ for the control after experimental periods. The cumulative $CO_2$ emission was slightly decreased in biochar input treatment compared to the control. It was appeared that cumulative $N_2O$ emissions were $2,890.6mg\;N_2O/m^2$ for control, 379.7 to $525.2mg\;N_2O/m^2$ for biochar input treatment at the end of experiment. All biochar treatments were found to significantly reduce $N_2O$ emission by 82~87%. Consequently the biochar from byproducts such as pear branch, rice hull and bean straw could suppress the soil $N_2O$ emission. The results from the study imply that biochar can be utilized to reduce greenhouse gas emission from the upland field.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.294-307
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• 2011

This experiment carried out to confirm characteristics of macrogranule (GG) for herbicidal efficacy by using remote-controlled aerial application (RCAA) to control annual and perennial weeds in rice paddy field, application methods, and application times of formulation types. Particle of 500 g GG having average diameter of 2.5~3 mm was over 85 percent, the bulk density of the particle was $0.2\sim0.4g\;mL^{-1}$ and the particle was water floating granule. Active ingredients and external form of halosulfuronmethyl+mefenacet GG remained stable under condition of storage stability test. The disintegration time of the GG was faster as the water temperature was increased. But disintegration time was not affected by pH on the water conditions. By using hand, spoon and power applicator, drift distances of GG were 4~5m, 7 m and 10~12 m, respectively. GG showed good herbicidal efficacy and plant safety in all of the application methods such as, using hand, spoon, power applicator and RCAA. Application times of GG, GR, SC and TB by hand in $4,000m^2$ were 38 min. 4 sec, 42 min. 20 sec, 38 min. 10 sec and 21 min. 4 sec, respectively, but application time of GG by using RCAA was 1 min 32 sec. According to appearance and characteristics of formulation types, suspension concentrate (SC) and GG were possible formulation types for RCAA.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.321-327
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• 2006

In Korea, there is a growing competitive for water resources between industrial, domestic and agricultural consumer, and the environment as many other OECD countries. The demand on water use is also affecting aquatic ecosystems particularly where withdrawals are in excess of minimum environmental needs for rivers, lakes and wetland habits. OECD developed three indicators related to water use by the agriculture in above contexts : the first is a water use intensity indicator, which is expressed as the quantity or share of agricultural water use in total national water utilization; the second is a water stress indicator, which is expressed as the proportion of rivers (in length) subject to diversion or regulation for irrigation without reserving a minimum of limiting reference flow; and the third is a water use efficiency indicator designated as the technical and the economic efficiency. These indicators have different meanings in the aspect of water resource conservation and sustainable water use. So, it will be more significant that the indicators should reflect the intrinsic meanings of them. The problem is that the aspect of an overall water flow in the agro-ecosystem and recycling of water use not considered in the assessment of agricultural water use needed for calculation of these water use indicators. Namely, regional or meteorological characteristics and site-specific farming practices were not considered in the calculation of these indicators. In this paper, we tried to calculate water use indicators suggested in OECD and to modify some other indicators considering our situation because water use pattern and water cycling in Korea where paddy rice farming is dominant in the monsoon region are quite different from those of semi-arid regions. In the calculation of water use intensity, we excluded the amount of water restored through the ground from the total agricultural water use because a large amount of water supplied to the farm was discharged into the stream or the ground water. The resultant water use intensity was 22.9% in 2001. As for water stress indicator, Korea has not defined nor monitored reference levels of minimum flow rate for rivers subject to diversion of water for irrigation. So, we calculated the water stress indicator in a different way from OECD method. The water stress indicator was calculated using data on the degree of water storage in agricultural water reservoirs because 87% of water for irrigation was taken from the agricultural water reservoirs. Water use technical efficiency was calculated as the reverse of the ratio of irrigation water to a standard water requirement of the paddy rice. The efficiency in 2001 was better than in 1990 and 1998. As for the economic efficiency for water use, we think that there are a lot of things to be taken into considerations to make a useful indicator to reflect socio-economic values of agricultural products resulted from the water use. Conclusively, site-specific, regional or meteorogical characteristics as in Korea were not considered in the calculation of water use indicators by methods suggested in OECD(Volume 3, 2001). So, it is needed to develop a new indicators for the indicators to be more widely applicable in the world.

• Journal of the Korean Society of Food Culture
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• v.18 no.6
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• pp.551-561
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• 2003

To determine the conditions of the fermentation and storage for Chonggak kimchi in kimchi refrigerator, prepared Chonggak kimchi took into kimchi refrigerators which were controlled at four different modes of the fermented temperature and time, and fermented and kept for 16 weeks. The pH in Chonggak kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ dropped greater than all of kimchi fermented at other combinations, and the changes of pH at any combinations were not greater than those in Baechu kimchi, because pH in Chonggak kimchi did not dropped below 4.5. Acidities in Chonggak kimchi were greatly increased at higher temperature. The acidity in Chonggak kimchi during the first week of fermentation was lower than that in Baechu kimchi and then it was rather higher because of the addition of waxy rice paste. In texture, puncture force of Chonggak kimchi was decreased slowly until 8 weeks of fermentation and then did not changed much and the highest values showed in Chonggak kimchi stored directly at $-1^{\circ}C$ without any fermentation. In sensory evaluation, the scores for the carbonated flavor and the sourness were the highest in Chonggak kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$, but the lowest in Chonggak kimchi stored directly at $-1^{\circ}C$ without any fermentation because of some undesirable flavors. The lowest hardness showed in Chonggak kimchi fermented at highest temperature and the best hardness was in Chonggak kimchi fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$. The appearance was the best in Chonggak kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ and the worst was in Chonggak kimchi stored directly at $-1^{\circ}C$ without any fermentation. The overall acceptability of Chonggak kimchi fermented at $20^{\circ}C$ for 24 hours/stored at $-1^{\circ}C$ was good after 4 weeks of fermentation, but in Chonggak kimchi fermented at $5^{\circ}C$ for 3 days or 6 days/stored at $-1^{\circ}C$ it was good after 6 weeks. Total microbial counts in most of Chonggak kimchi were reached to a maximum number within 7 days, and then decreased similarly at all modes. Leuconostoc spp. and Lactobacillus spp. increased to maximum number of $1.48{\times}10^9\;and\;5.62{\times}10^9$, respectively, in Chonggak kimchi fermented for 7 days. Yeast counts showed a increasing trend not depends on fermenting temperature and they were lower counts than those in Baechu kimchi. Waxy rice paste which added to Chonggak kimchi resulted in increasement of glucose as a carbon source and stimulated to reproduce the microbes in Chonggak kimchi.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.264-281
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• 1996

As a consequence of wide use of herbicides, Eleocharis kuroguwai Ohwi became a dorminant problem weed for rice cultivation in Korea. To understand the establishment of the weed, experiments on physio-ecological characteristics were carried out sprouting and occurrence, the results could be summarized as follows: Sprouting percentage remained 68 to 73% until the time of field emergence, indicating many of the them are still dormant. The proportion of the dormant tubers were greater for the smaller than the bigger tubers. Apical dominance was apparent in sprouting, with 84% of tuber sprouted from only one of the apical buds. Tubers sprouted from 2 or 3 buds were less than 20%, and were mostly from the bigger tubers. When the shoot growth was compared, by controlling the others, ones from apical and the next 3 buds showed similar vigorous growth, but the later ones showed poorer growth. For the longevity of tubers, deep soil storage appeared to be better than storage in temperature controlled room to 2~$3^{\circ}C$. Emergence of E. kuroguwai was better in clay soil than in sand, and the possible depth for emergence in clay soil appeared to be up to 21cm, but was 15cm in sand. When tubers were exposed to salt solutions before emergence tests, E. kuroguwai appeared to be much sensitive to salts than S.planiculmis. Among the tubers formed in previous year, 12.7% remained still viable until the end of next crop season, but with relatively strong dormancy. The first emergence was about 10 days after planting at ordinary cropping seasons, and the days to the maximum shoot number stage were 60~90 from planting. The duration was extended at early transplanting, and shoot number, leaves per shoot, and tubers developed per plant were also greater at early plantings. The 6th order offshoots were developing when E. kuroguwai was planted at early season. When planted at later seasons, generation and the number of offshoots was reduced planted at early season. When planted at later seasons, generation and the number of offshoots was reduced and the number of tubers, runner and rhizome lengths was also reduced.

• Journal of the Korean Society of Food Culture
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• v.1 no.3
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• pp.267-278
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• 1986

The evolution of Korean fish fermentation technology was reviewed from the old literatures and the on-going processes were surveyed. The principles involved in the traditional fermentation methods were explained by the recent scientific findings. The fish fermentation technology be classified into two groups; jeot-kal process, where. salt is the only material added to the fish for fermentation, and sik-hae process, where cooked cereals, garlic and red pepper powder are added to the salted fish. A total of 46 kinds of jeot-kal was identified in a survey, depending on the raw materials used. The characteristic feature of Korean jeot-kal process is to produce fermented products which still has original shape after 2-3 months of fermentation to be used for side-dishes of rice meal, as well as fish sauce by keeping these products for longer time (over 6 months) for severe ansymematic hydrolysis to be used for the subingredient of Kimchi (Korean fermented vegetable food). The taste of jeot-kal is formed by the protein hydrolymates due to the action of salt-tolerant Pediococcus, Bacillus, Halobacterlum etc. When the taste of jeot-kal deteriorates, yeasts appear to dominate. In ski-hae fermentation, the safety of preserved fish is kept by the rapid decrease in pH resulting from the acid fermentation of added cereals. The roles of cid forming bacteria and proteloytic bacteria are important. The fermentation is completed in 2 weeks and the excess production of acid during prolonged storage limits the taste acceptability. The fish fermentation technology in Korea stands at important position in Korean food science and technology. since the processes of jeot-kal and soysauce have same root in the principle of microbial proteolysis and the processes of sik-hae and Kimchi in the microbial acid production principles.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.667-676
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• 2007

This study was conducted to determine effects of cellulolytic microbes inoculation to sawdust-based spent mushroom substrate(SMS) during deepstacking on fermentation parameters, total microbial counts and cellulolytic enzyme activity and to on SMS nutrients utilization by sheep. For sheep metabolism trials, six sheep(ram, average 54.8kg) were fed a Control diet(70% concentrates, 15% rice straw and 15% SMS with no microbial treatment on a dry basis) and a Treatment diet(the same diet including SMS with a microbial treatment) for 2 trials. Spent mushroom substrates with or without a microbial(4 strains including 1 strain of Enterobacter ludwigii, 1 strain of Bacillus cereus and 2 strains of Bacillus subtillis) treatment (1% of SMS on wet basis) were deepstacked for 7 days. The internal temperatures in 1.2 M/T of SMS deepstacks reached to 50±5℃ within 7 days of storage. Total microbial counts remarkably decreased (P<0.05) with a deepstacking process and were not affected(P>0.05) by the microbial treatment. For fibrolytic enzyme activity, CMCase and xylanase activities were decreased(P<0.05) by a deepstacking process. After deepstacking, the microbial treatment showed about 2.5-times higher(P<0.05) for CMCase activity and about 4-times higher(P<0.05) for xylanase activity than those of the Control. Activities of ligninolytic enzymes such as laccase and MnP were not affected by the microbial treatment. The sheep fed the microbially treated SMS diet had a tendency of greater total tract digestibilities of ash(P=0.051), NFE (P=0.071), hemicellulose(P=0.087) and NDF(P=0.096) than those fed the untreated SMS diet. Nitrogen balance of sheep was not affected(P>0.05) by feeding of microbially treated SMS. Accordingly, these results indicate that cellulolytic microbes inoculation during deepstacking of SMS may improve the bio- utilization of SMS by sheep.