Absorption and Partition of $^{15}N-labeled$ Fertilizer in Rice under Different Nitrogen Application Time and Rate Conditions

Chun, Areum,Lee, Ho-Jin The Korean Society of Crop Science 2006 Korean journal of crop science Vol.51 No.1

The nitrogen (N) absorption and partition of the rice plants are important indicators that can be used to improve the N use efficiency (NUE) of the plants. Improving the plant NUE can help to avoid nutrient waste that may cause environmental pollution. To investigate the N absorption and partition of the rice plants, Hwaseongbyeo (Japonica) and Dasanbyeo (indica/japonica) were applied with N fertilizers at the rates of 60, 120, and 180 kg N per ha in paddy field. Also micro plots of $0.81m^2$ were established inside each plot for application of $^{15}N-labeled$ fertilizer. The differences in N utilization of the rice plants were associated with the total N absorption and partitioning after the heading stage. In the grain filling period, the increase of nitrogen content in the total and leaf blades of Dasanbyeo was higher than that of Hwaseongbyeo. Soil N was the main contributor for the increase of total N of Dasanbyeo during the grain filling period. The N fertilizer uptake rate of Hwaseongbyeo rapidly increased with the increment of N fertilization rate. In Dasanbyeo, N fertilizer uptakes were similar under all rates and times of N application. From heading stage to harvest, Dasanbyeo continued accumulating nitrogen, whereas Hwaseongbyeo had small changes. In conclusion, the difference in nitrogen absorption and partition after heading of the two cultivars was caused by the ability of Dasanbyeo to accumulate and remobilize soil nitrogen to the grains during the grain filling period.

Absorption and Partition of 15N-labeled Fertilizer in Rice under Different Nitrogen Application Time and Rate Conditions

Areum Chun,Ho Jin Lee 韓國作物學會 2006 Korean journal of crop science Vol.51 No.1

The nitrogen (N) absorption and partition of the rice plants are important indicators that can be used to improve the N use efficiency (NUE) of the plants. Improving the plant NUE can help to avoid nutrient waste that may cause environmental pollution. To investigate the N absorption and partition of the rice plants, Hwaseongbyeo (Japonica) and Dasanbyeo (indica/japonica) were applied with N fertilizers at the rates of 60, 120, and 180 kg N per ha in paddy field. Also micro plots of 0.81m2 were established inside each plot for application of 15N-labeled fertilizer. The differences in N utilization of the rice plants were associated with the total N absorption and partitioning after the heading stage. In the grain filling period, the increase of nitrogen content in the total and leaf blades of Dasanbyeo was higher than that of Hwaseongbyeo. Soil N was the main contributor for the increase of total N of Dasanbyeo during the grain filling period. The N fertilizer uptake rate of Hwaseongbyeo rapidly increased with the increment of N fertilization rate. In Dasanbyeo, N fertilizer uptakes were similar under all rates and times of N application. From heading stage to harvest, Dasanbyeo continued accumulating nitrogen, whereas Hwaseongbyeo had small changes. In conclusion, the difference in nitrogen absorption and partition after heading of the two cultivars was caused by the ability of Dasanbyeo to accumulate and remobilize soil nitrogen to the grains during the grain filling period.

Varietal Variation of Textural Properties of Cooked Rice by High Temperature during Grain Filling

Areum Chun,Jin Seok Lee,Kee Jong Kim,Yoon Hee Choi,Jun HwanKim 한국육종학회 2009 한국육종학회 학술발표회 발표요지 Vol.41 No.1

Comparison of Rice Amylose Analysis in Korea and Japan

Areum Chun,Mi-Ra Yoon,Sea-Kwan Oh,Dae-Jung Kim,Ha-Cheol Hong,Im-Soo Choi 한국작물학회 2010 한국작물학회 학술발표대회 논문집 Vol.2010 No.04

Measurement of amylose content is commonly employed as the predictor of rice quality. Amylose is usually measured by absorbance of the amylose-iodine complex by a variety of ways. However, the effort to standardize the way amylose is measured is still working through the world of rice research. For comparing rice amylose analysis methods in Korea and Japan, major japonica rice-producing countries, rice samples with different amylose contents were selected. The rice samples were harvested, dried and milled at the National Institute of Crop Science, Rural Development Administration in Suwon, Republic of Korea. Amylose contents (AC) were analyzed using Concanavalin A method and modified Juliano methods, as representative methods in Korea and Japan, respectively. The AC of rice starch by Concanavalin A method were ranged 9.4~28.8%, on the other hand, the AC of rice flour by modified Juliano method had a wider range AC, 8.7~41.8%; for example, AC of semi-waxy varieties had lower values and AC of high amylose varieties had higher values in modified Juliano methods, even more than 10%. High correlation coefficients between retrogradation (or gelatinization) and AC using Concanavalin A would indicate that the Concanavalin A method could be more explanatory for evaluating rice quality like gelatinization and retrogradation.

Effects of Ripening Temperature on Starch Structure and Gelatinization, Pasting, and Cooking Properties in Rice (<i>Oryza sativa</i>)

Chun, Areum,Lee, Ho-Jin,Hamaker, Bruce R.,Janaswamy, Srinivas American Chemical Society 2015 Journal of agricultural and food chemistry Vol.63 No.12

<P>The effect of ripening temperature on rice (<I>Oryza sativa</I>) grain quality was evaluated by assessing starch structure and gelatinization, pasting, and cooking properties. As the ripening temperature increased, the amylose content and number of short amylopectin chains decreased, whereas intermediate amylopectin chains increased, resulting in higher gelatinization temperatures and enthalpy in the starch. These results suggested that an increase in cooking temperature and time would be required for rice grown at higher temperatures. A high ripening temperature increased the peak, trough, and final viscosities and decreased the setback due to the reduction in amylose and the increase in long amylopectin chains. With regard to starch crystallinity and amylopectin molecular structure, the highest branches and compactness were observed at 28/20 °C. Rice that was grown at temperatures above 28/20 °C showed a deterioration of cooking quality and a tendency toward decreased palatability in sensory tests.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2015/jafcau.2015.63.issue-12/jf504870p/production/images/medium/jf-2014-04870p_0003.gif'></P>

Quality of Head and Chalky Rice and Deterioration of Eating Quality by Chalky Rice

Areum Chun,Jin Song,Kee-Jong Kim,Ho-Jin Lee 한국작물학회 2009 Journal of crop science and biotechnology Vol.12 No.4

Chalk, an opaque area in the rice grain, is an important quality characteristic in rice and occurs most commonly when grains are exposed to high temperatures during development. Chalky rice decreases the value of rice because of its undesirable appearance and eating quality for consumers. We investigated the chemical composition, morphological structure, cooking, texture properties of cooked rice, and pasting and gelatinization properties to evaluate the reason for the deterioration in eating quality of chalky rice. The ultra-structure of chalky kernels differed greatly from that of head rice. Chalky grain had more air spaces, a disordered cellular structure, and rounder amyloplasts than head rice. Chalky rice absorbed water more rapidly during cooking and had a slightly larger expansion volume than head rice, confirming its loose starch granule structure. The lower amylose content of chalky kernels caused a more soluble solid and higher iodine index during cooking indicating their lower eating quality compared to translucent kernels. The lower gelatinization temperature of chalky kernels was suggested to be related to a more short-branch chain amylopectin structure. Chalky kernels resulted in a harder and less adhesive (or sticky) texture of cooked rice, requiring more time for chewing than those of head kernels, caused by its low protein content. The palatability of cooked rice showed a linear decrease with increasing chalky rice proportion in the sensory evaluation. In amylography, the peak and final viscosities greatly decreased when the chalky rice proportion increased from 0 to 5%. It indicated that chalky rice kernels induce quality deterioration even at 5%. Chalk, an opaque area in the rice grain, is an important quality characteristic in rice and occurs most commonly when grains are exposed to high temperatures during development. Chalky rice decreases the value of rice because of its undesirable appearance and eating quality for consumers. We investigated the chemical composition, morphological structure, cooking, texture properties of cooked rice, and pasting and gelatinization properties to evaluate the reason for the deterioration in eating quality of chalky rice. The ultra-structure of chalky kernels differed greatly from that of head rice. Chalky grain had more air spaces, a disordered cellular structure, and rounder amyloplasts than head rice. Chalky rice absorbed water more rapidly during cooking and had a slightly larger expansion volume than head rice, confirming its loose starch granule structure. The lower amylose content of chalky kernels caused a more soluble solid and higher iodine index during cooking indicating their lower eating quality compared to translucent kernels. The lower gelatinization temperature of chalky kernels was suggested to be related to a more short-branch chain amylopectin structure. Chalky kernels resulted in a harder and less adhesive (or sticky) texture of cooked rice, requiring more time for chewing than those of head kernels, caused by its low protein content. The palatability of cooked rice showed a linear decrease with increasing chalky rice proportion in the sensory evaluation. In amylography, the peak and final viscosities greatly decreased when the chalky rice proportion increased from 0 to 5%. It indicated that chalky rice kernels induce quality deterioration even at 5%.

도정도에 따른 소곡주의 품질 및 기호도 변이

천아름(Areum Chun),김대중(Dae-Jung Kim),윤미라(Mi-Ra Yoon),오세관(Sea-Kwan Oh),최임수(Im-Soo Choi),홍하철(Ha-Cheol Hong),김연규(Yeon-Gyu Kim) 한국식품영양과학회 2012 한국식품영양과학회지 Vol.41 No.1

한국 전통주인 ‘한산 소곡주’의 품질 연구를 위해 원료인 찰벼의 도정 정도에 따른 주질 특성을 살펴보았다. 소곡주의 원료로 주로 사용되는 동진찰벼를 현미 중량을 기준으로 92%(10분도), 84%(20분도), 76%(30분도), 68%(40분도) 수준으로 도정하여 소곡주를 제조하여 그 원료곡과 소곡주의 품질 특성과 그에 따른 기호도 변화를 분석하였다. 먼저 원료곡의 품질 특성은 도정도가 증가할수록 단백질, 지방 및 회분 함량이 급격히 감소하였으며 색 및 형태적인 변화를 수반하였고, 이는 기존의 보고와 일치하는 결과였다. 도정도에 따른 수분함량의 차이는 없었으며, 10분도를 제외하고는 물리적인 경도 차이도 나타나지 않아, 10분도 이상 시료의 경도 감소는 주로 단백질 함량의 감소와 연관된 것으로 판단되었다. 호화특성 또한 도정도가 증가할수록 전체적인 점성이 증가하는 양상을 뚜렷이 보임을 알 수 있었다. 이는 일차적으로 호화를 억제하는 단백질, 지방 성분들의 감소에 따른 것으로 판단되었으며, 이차적으로 아밀로펙틴 분지 구조가 도정도 증가에 따라 중쇄는 증가하고 장쇄는 감소하는 변화를 나타내어 이에 따른 영향이 있을 것으로 추정되었다. 도 정도에 따른 소곡주 품질은 먼저 전분함량의 증가에 따라 제조수율이 증가하였으며, 알코올 함량의 유의한 차이는 없었으나, 당도와 유리당 함량이 감소하고 총 산도는 증가하여 단맛이 감소하고 신맛이 증가함을 확인할 수 있었다. 색 특성도 20분도 이상부터 명도는 감소하고 황색도가 증가하는 경향이 뚜렷하였으나 소곡주 색 특성에 대한 연구가 전무하여 관련 연구가 필요할 것으로 판단되었다. 도정도별로 소곡주의 소비자 기호도 검사를 실시한 결과 원료곡의 도정도가 증가할수록 소곡주의 소비자 기호도가 떨어지는 것으로 나타났다. 또한 소비자 기호도와 도정도에 따른 소곡주 품질의 상관관계 분석 결과, 소비자 기호도가 소곡주의 당도 및 포도당 함량, pH 및 원료곡의 단백질 함량과 상관관계를 나타내어, 원료곡 도정에 따른 소곡주 고유의 달고 풍부한 맛의 감소가 낮은 소비자 기호도의 원인인 것으로 판단되었다. Sogokju, a Korean glutinous rice wine and one of the oldest Korean traditional wines, is famous for its unique taste acquired from a 100-day incomplete fermentation process. This study investigated the effects of the degree of rice milling on the physicochemical and sensory characteristics of Sogokju. It evaluated the physicochemical characteristics, pasting and color properties, and structural properties of starch using four different degrees of milled rice (Oryza sativa L.) cultivar Dongjinchalbyeo. Samples of brown rice with milling yields of 92%, 84%, 76%, and 68% were produced using both abrasive and friction whiteners. This study showed that the protein, lipid, and ash content of milled rice decreased as the degree of milling increased. The lower hardness of the kernel below milling yield 92% suggested that milling may be related to the lower protein content of the kernel. The pasting curve showed a significant increase in viscosity properties as the degree of milling increased. This is due to the decrease in protein and lipid content, the increase in starch content, and the difference in amylopectin chain-length distribution. Further milling of white rice, based on 92% milling yield, had an effect on the amylopectin chain-length distribution due to the degree of polymerization (DPn) of 37~60. The long chain of amylopectin also contributed to the viscosity. The increase in the degree of milling decreased the glucose and total sugar content of Sogokju. However, it increased the total acidity of Sogokju. Moreover, the lightness of Sogokju decreased while its yellowness increased. These results indicate that the degree of milling can alter the taste and color of Sogokju. The sensory evaluation showed that the increase in the degree of milling decreased consumer preference for Sogokju. The sensory score for Sogokju was positively correlated with its brix degree, glucose content, pH, and protein content of raw rice.

Ryanodine Receptor-mediated Calcium Release Regulates Neuronal Excitability in Rat Spinal Substantia Gelatinosa Neurons

Areum Park,Sang Woo Chun 대한구강생물학회 2015 International Journal of Oral Biology Vol.40 No.4

Nitric Oxide (NO) is an important signaling molecule in the nociceptive process. Our previous study suggested that high concentrations of sodium nitroprusside (SNP), a NO donor, induce a membrane hyperpolarization and outward current through large conductances calcium-activated potassium (BKca) channels in substantia gelatinosa (SG) neurons. In this study, patch clamp recording in spinal slices was used to investigate the sources of Ca2+ that induces Ca2+-activated potassium currents. Application of SNP induced a membrane hyperpolarization, which was significantly inhibited by hemoglobin and 2-(4-carboxyphenyl) -4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide potassium salt (c-PTIO), NO scavengers. SNP-induced hyperpolarization was decreased in the presence of charybdotoxin, a selective BKCa channel blocker. In addition, SNP-induced response was significantly blocked by pretreatment of thapsigargin which can remove Ca2+ in endoplasmic reticulum, and decreased by pretreatment of dentrolene, a ryanodine receptors (RyR) blocker. These data suggested that NO induces a membrane hyperpolarization through BKca channels, which are activated by intracellular Ca2+ increase via activation of RyR of Ca2+ stores.

Pre- and Postsynaptic Actions of Reactive Oxygen Species and Nitrogen Species in Spinal Substantia Gelatinosa Neurons

Areum Park,Sang Woo Chun 대한구강생물학회 2018 International Journal of Oral Biology Vol.43 No.4

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of O 2 ⦁- and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DL- penicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

Role of microglial activation on neuronal excitability in rat substantia gelatinosa

Areum Park,Sang Woo Chun 대한구강생물학회 2020 International Journal of Oral Biology Vol.45 No.4