• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1392-1396
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• 2009

Antioxidative effects of rice hull extracts pre-treatment with various organic acids were evaluated. After incubating rice hull in 50 mM of five different organic acid solutions (acetic, citric, lactic, phosphoric, and tartaric acid) for 18 hours at room temperature, hydrothermal treatment at $121^{\circ}C$ for 30 min was carried out. Antioxidant activity of the rice hull extract was evaluated by determining total phenol contents (TPC), DPPH radical scavenging activity (RSA), reducing power (RP), and ABTS RSA. Pre-treatment with 50 mM phosphoric acid significantly increased TPC, DPPH RSA, and RP, while it decreased ABTS RSA. The effect of phosphoric acid concentration was also determined. TPC and DPPH RSA of rice hull extract increased with concentration of pre-treated phosphoric acid; in contrast, RP showed the reverse pattern. The results indicated that pre-treatment of rice hull with organic acid was very effective for increasing phenolic compounds and antioxidant activity of rice hull extract.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.4
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• pp.406-412
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• 2014

The influence of rainfall during the ripening stage on pre-harvest sprouting, seed viability, and seed quality was investigated in two Korean rice cultivars, Shindongjin and Hopum. When the rainfall was artificially treated in a greenhouse, HP started to pre-harvest sprouting at three days of rainfall treatment (DRT), but Shindongjin did not show pre-harvest sprouting at 40 DAH treatment and just 0.3~0.8% at 50 DAH, which was much lower than 15.3~25.8% of Hopum in the same treatment. After harvest, the seed germination of Hopum decreased about 10~25% compared to non-treated seeds, but that of Shindongjin decreased much little rate than that of Hopum. The seed longevity tested by accelerated aging decreased with prolonged rainfall period in both cultivars, but the varietal difference was clear; Shindongjin could withstand longer accelerated aging than Hopum. Shindongjin maintained its germination (>50%) ability after 15 days of accelerated aging regardless of the rainfall treatment period and time, but Hopum dropped below 50% germination ability after only 5 days of accelerated aging. In conclusion, rainfall during the ripening stage induced not only pre-harvest sprouting, but also reduced seed quality and longevity during storage, which varied between two cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.45-50
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• 1971

For the purpose of finding out the effect of heat treatment on biological response and mutation rate, rice seeds were heat treated before and after gamma irradiation. 1. At a dose of 20 KR, pre-irradiation heat treatment showed reduced biological damage and increased mutation rate as compared with non-heat treatment. 2. Mutation frequency was increased in post-treatment of heat shock than in pre-irradiation heat treatment and non-heat treatment. 3. Pre-irradiation heat treatment at 6$0^{\circ}C$ for 30 minutes markedly reduced the biological damage and increased the mutation rate. 4. Mutation spectrum in heat treatment was different from non-treatment.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1760-1768
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• 2019

The use of lignocellulosic biomass such as rice straw can help subsidize the cost of producing value-added chemicals. However, inhibitory compounds, such as phenolics, produced during the pre-treatment of biomass, hamper the saccharification process. Laccase and electrochemical stimuli are both well known to reduce phenolic compounds. Therefore, in this study, we implemented a bioelectrochemical detoxification system (BEDS), a consolidated electrochemical and enzymatic process involving laccase, to enhance the detoxification of phenolics, and thus achieve a higher saccharification efficiency. Saccharification of pretreated rice straw using BEDS at 1.5 V showed 90% phenolic reduction (Ph_r), thereby resulting in a maximum saccharification yield of 85%. In addition, the specific power consumption when using BEDS (2.2 W/Kg Ph_r) was noted to be 24% lower than by the electrochemical process alone (2.89 W/kg Ph_r). To the best of our knowledge, this is the first study to implement BEDS for reduction of phenolic compounds in pretreated biomass.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.277-283
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• 2017

To produce sweet liquor without artificial sweeteners, 8 traditional rice pre-treatment methods (juk, beombeok, seolgitteok, gumeongtteok, mulsongpyeon, injeolmi, gaetteok, and godubap) were analyzed in this study. The formation of sugars with the help of ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase using nuruk as a substrate has been previously confirmed. During the early stages of the pre-treatment processes, the amount of maltose produced (in descending order of its concentration) by ${\alpha}$-amylase was observed to be as follows: gaetteok > seolgitteok > beombeok > mulsongpyeon > juk > injeolmi > gumeongtteok > godubap. However, changes in maltose concentrations with respect to the pre-treatment processes after 48 hours were observed to be as follows: injeolmi > beombeok = godubap > gumeongtteok > gaetteok = mulsongpyeon > seolgitteok > juk. Maltose produced using either ${\alpha}$-amylase or ${\beta}$-amylase showed similar results. Glucoamylase produced 10 mg/ml of glucose during the godubap process, which was the highest amount of glucose among all the methods. Moreover, when ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase were used concurrently, glucoamylase increased glucose production in the later stages. Therefore, the possibility of producing sweet liquor without employing artificial sweeteners was confirmed, even if the amount of sugar in the liquor varied with the pre-treatment process.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.9-13
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• 2000

Wood demand is increasing more and more, but world has been confronted with decreasing forest resources. Korea has to depend upon foreign wood and wood-based products for more than 95 percent of total domestic demand per year. In order to heighten self-sufficiency for wood supply and demand, we have to develop wood substitutes. Rice hull is the cheapest agricultural by-product we can get in Korea, more over the production of rice hull amounts to 1 million tons per year. This study was carried out to utilize rice hull and to decide the optimum condition of rice hull pretreatment for manufacture of rice hull board. Steam explosion method gave the best result, and the next boiling treatment of 1 hour, the last 1 hour treatment with 1% NaOH solution. Optimum conditions of explosion method were 20kgf/$cm^2-1$ minute and 25kgf/$cm^2-1$ minute. Rice hull board made with exploded rice hull met the KS standard(KS F 3104, 1997) and showed the same strength as a control, PB. And also the 1 hour boiling treatment was more effective than the 1 hour treatment with 1% NaOH solution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.80-84
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• 2002

In spite of simple and cheap cultivation method, water broadcast-seeded rice demonstrates uneven and unstable seedling establishment per unit land area and requires more herbicide and labor-input for weed control. Three experiments were conducted in a phytotron at 18$^{\circ}C$ to evaluate the adaptability of seed-mat mulching cultivation technologies in water seeded rice for the uniform seedling establishment and the inhibition of weed occurrence without herbicide application. Five different kinds of mat with different mesh sizes and fabric properties were tested. The emergence of rice was the highest in Lawn-mat treatment, being comparable with the control, in which seeds were sown without mat. The Lawn-mat also exhibited the lowest mat tension. Mat tension may influence the emergence of rice. And once it was soaked in water, it didn't maintain its original shape any more. The emergence rate of rice was the lowest in Safer-mat treatment. In Lawn-mat treatment, which was the most effective for rice emergence in the first study, the differences of emergence and seedling establishment of rice depending on the seeding position (upper, beneath, and between mats) treatments were negligible, while they were higher in dry seeds than in pre-germinated seeds treatment. The emergence as affected by the kinds of mat also showed the same trend when tested using barnyard grass. Depending on the kinds of mat, the inhibition effect of weeds was the greatest in Safer-mat and the poorest in Lawn-mat. These results strongly suggest the possibility that the uniform seedling establishment and weed management without chemical could be achieved simultaneously by seed-mat mulching through the combination of effective mat for the emergence of rice and another efficient mat for the inhibition of weed occurrence. This possibility was also tested in the field.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.71-77
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• 2012

In order to find a feasibility of applying an agricultural biomass to the anaerobic digestion system, the effects of pre-treatment of rice straw was investigated by different sizes,temperatures, ultrasonic frequencies, and with/without NaOH treatment on the change of soluble organic matter, which is generated most dominantly in Korea. It was observed that SCOD(soluble chemical oxygen demand) as the index for the decomposition of rice straw increased with the smaller particle size, higher reaction temperature and alkali treatment. With treatment of 5% NaOH, it was shown that the highest concentrations of SCOD were observed at 9,000 mg $L^{-1}$ and 6,000mg $L^{-1}$ at $35^{\circ}C$ and $55^{\circ}C$, respectively. Agitating with ultrasonic irradiation could be enhanced SCOD of rice straw less than 3 cm with 40 kHz of ultrasound. Optimal RPM in this study was at 150 rpm regardless of reaction temperatures.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.135-142
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• 2010

This study was carried out to establish the optimum pre-wilting time for the high-quality silage production of whole crop oat. Plants were harvested for three time at intervals of 10 days after heading (DAH) and silage production was conducted after the pre-wilting treatment of 0, 4, 8 and 32 hours, respectively. Results showed to attain a proper moisture content for profitable silage production, which was an optimal content for making silage, by pre-wilting oat for 4 hours after harvest at either 20 days after heading or harvesting 30 DAH(days after heading). As the feed value of silage, the processing of proper moisture contents showed that crude protein contents were high and the entire feed value showed higher than others. High content of lactic acid and the low content of acetic and butyric acid showed on 60~65% the moisture conditions of silage. There was desired that whole crop oat was pre-wilting on 4 hours and harvested at about 20~30 DAH and after that, even if harvesting at once, it was judged that it could produce good quality silage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.50-55
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• 2003

Herbicidal activity of $\delta$-aminolevulinic acid(ALA), an intermediate for the biosynthesis of tetrapyrroles such as chlorophyll, heme, bacteriochlorophyll, and vitamin $\textrm{B}_{12}$ analogues, was examined to determine the variation in phytotoxic potential against different plant species as affected by different application methods. Seed-soaking treatment, ALA at low concentrations did not affect shoot and root lengths of test plants while at highest concentration reduced them by 20 to 30%. Alfalfa showed the most tolerant response to ALA in both pre- and post-emergence application, and followed by rice. When applied with pre-emergence, cotyledons of Chinese cabbage were severely bleached with 0.5 mM of ALA at 24 hrs after application, and root growth of rice, barnyard grass, and alfalfa was significantly inhibited with increasing of concentration. With post-emergence application, ALA at 2 to 4 mM reduced shoot and root growths of Chinese cabbage and barnyard grass completely. Herbicidal effects of ALA were more enhanced in the treatment combined with 2,2-dipyridyl sthan single application in barnyard grass and Chinese cabbage. The results suggest that alfalfa was the most tolerant to ALA among the tested plants, and that post-emergence application of ALA exhibited greatest photodynamic activity against tested plants.