Changes in Water Content Affect the Post-Milling Quality of Paddy Rice Stored at Low Temperature

( Young Keun Kim ),( Seong Gi Hong ),( Sun Ho Lee ),( Jong Ryul Park ),( Jung Seob Choe ) 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature of bulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and the rate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storage bags kept at low temperature and grain temperature after exposure to room temperature were measured. Experiments were conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results: It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation, and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminate surface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, but water content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred, regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensation occurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage did not show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from low temperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that was milled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, all portions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could be significantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow the increase of grain temperature and prevent surface condensation.

Changes in Water Content Affect the Post-Milling Quality of Paddy Rice Stored at Low Temperature

김영근,홍성기,이선호,박종렬,최중섭 한국농업기계학회 2014 바이오시스템공학 Vol.39 No.4

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature ofbulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and therate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storagebags kept at low temperature and grain temperature after exposure to room temperature were measured. Experimentswere conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results:It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation,and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminatesurface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, butwater content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred,regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensationoccurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage didnot show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from lowtemperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that wasmilled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, allportions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could besignificantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow theincrease of grain temperature and prevent surface condensation.

Effects of Ar gas Composition on the Characteristics of Surface Layers Formed on AISI 316L Stainless Steel During Low-Temperature Plasma Nitriding after Low-Temperature Plasma carburizing

이인섭 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.5

A 2-step low-temperature plasma process (the combined carburizing and post- nitriding) increases both the surface hardness and the thickness of the hardened layer and the corrosion resistance compared to individually processed low-temperature nitriding and low-temperature carburizing techniques. The 2-step low-temperature plasma process was carried out to improve both the surface hardness and the corrosion resistance of AISI 316L stainless steel. The influence of the Ar gas level in the atmosphere during the nitriding step on the surface properties was investigated. The expanded austenite (rN) was formed on all the treated surface. The thickness of rN was increased up to about 15 μm, and the thickness of the entire hardened layer was determined to be about 40 μm. The surface hardness reached 1200 HV0.1, which is about 5 times higher than that of the untreated sample (250 HV0.1). The thickness of the rN layer increased with increasing Ar gas content in the atmosphere. The corrosion resistance in the austenitic stainless steel processed by using the 2-step low temperature plasma was also much enhanced compared to that in the untreated austenitic stainless steel due to the high concentration of N on the surface. A 2-step low-temperature plasma process (the combined carburizing and post- nitriding) increases both the surface hardness and the thickness of the hardened layer and the corrosion resistance compared to individually processed low-temperature nitriding and low-temperature carburizing techniques. The 2-step low-temperature plasma process was carried out to improve both the surface hardness and the corrosion resistance of AISI 316L stainless steel. The influence of the Ar gas level in the atmosphere during the nitriding step on the surface properties was investigated. The expanded austenite (rN) was formed on all the treated surface. The thickness of rN was increased up to about 15 μm, and the thickness of the entire hardened layer was determined to be about 40 μm. The surface hardness reached 1200 HV0.1, which is about 5 times higher than that of the untreated sample (250 HV0.1). The thickness of the rN layer increased with increasing Ar gas content in the atmosphere. The corrosion resistance in the austenitic stainless steel processed by using the 2-step low temperature plasma was also much enhanced compared to that in the untreated austenitic stainless steel due to the high concentration of N on the surface.

Changes in Water Content Affect the Post-Milling Quality of Paddy Rice Stored at Low Temperature

Kim, Young-Keun,Hong, Seong-Gi,Lee, Sun-Ho,Park, Jong-Ryul,Choe, Jung-Seob Korean Society for Agricultural Machinery 2014 바이오시스템공학 Vol.39 No.4

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature of bulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and the rate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storage bags kept at low temperature and grain temperature after exposure to room temperature were measured. Experiments were conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results: It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation, and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminate surface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, but water content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred, regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensation occurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage did not show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from low temperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that was milled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, all portions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could be significantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow the increase of grain temperature and prevent surface condensation.

Detection of Temperature Stress Using Chlorophyll Fluorescence Parameters and Stress-related Chlorophyll and Proline Content in Paprika (Capsicum annuum L.) Seedlings

Shiva Ram Bhandari,Yong Hyeon Kim,Jun Gu Lee 한국원예학회 2018 원예과학기술지 Vol.36 No.5

Thirty three-day-old paprika (Capsicum annuum L.) seedlings were grown under different temperature conditions (low: 10°C, moderate: 25°C, and high: 35°C) in a closed plant production system for 32 days and their chlorophyll (Chl) fluorescence and growth parameters, and Chl and proline contents were measured at 0, 1, 2, 4, 8, 16, 24, and 32 days after the initiation of treatment. Minimal fluorescence (F0) sharply increased from 8 days and continued until the end of the experimental period under all three temperature treatments, with the highest increase at the low temperature condition. Maximum quantum yield (Fv/Fm) and the efficiency of excitation capture of open photosystem II (PSII) center (F’v/F’m) significantly decreased at low temperature compared with those at moderate and high temperatures. Non-photochemical quenching (NPQ) and the ratio of the fluorescence decrease (Rfd) were significantly affected, particularly at the high temperature, followed by the low and moderate temperatures; quantum yield of non-regulated energy dissipation in PSII (ϕNO) increased under all treatments. Furthermore, Chl content showed a relatively greater decrease at the low temperature compared to the high temperature throughout the experiment; moderate temperature showed a stable chlorophyll content throughout the experiment. Proline concentration increased significantly at the high and low temperatures, but not under moderate temperature. Plant height and shoot and root weight were the lowest at the low temperature. Overall, our results suggest that paprika plants were more severely affected by low temperature than high temperature with respect to photosynthetic activity as well as growth, which was significantly slowed at low temperature.

Phenotyping of Low-Temperature Stressed Pepper Seedlings Using Infrared Thermography

Park, Eunsoo,Hong, Suk-Ju,Lee, Ah-Yeong,Park, Jongmin,Cho, Byoung-Kwan,Kim, Ghiseok Korean Society for Agricultural Machinery 2017 바이오시스템공학 Vol.42 No.3

Purpose: This study was performed to evaluate the feasibility of using an infrared thermography technique for phenotype analysis of pepper seedlings exposed to a low-temperature environment. Methods: We employed an active thermography technique to evaluate the thermal response of pepper seedlings exposed to low-temperature stress. The temperatures of pepper leaves grown in low-temperature conditions ($5^{\circ}C$, relative humidity [RH] 50%) for four periods (6, 12, 24, and 48 h) were measured in the experimental setting ($23^{\circ}C$, RH 70%) as soon as pepper seedling samples were taken out from the low-temperature environment. We also assessed the visible images of pepper seedling samples that were exposed to low-temperature stress to estimate appearance changes. Results: The greatest appearance change was observed for the low-temperature stressed pepper seedlings that were exposed for 12 h, and the temperature from these pepper seedling leaves was the highest among all samples. In addition, the thermal image of low-temperature stressed pepper seedlings for 6 h exhibited the lowest temperature. Conclusions: We demonstrated that the leaf withering owing to the water deficiency that occurred under low-temperature conditions could induce an increase in temperature in plant leaves using the infrared thermography technique. These results suggested that the time-resolved and averaged thermal signals or temperatures of plants could be significantly associated with the physiological or biochemical characteristics of plants exposed to low-temperature stress.

Phenotyping of Low-Temperature Stressed Pepper Seedlings Using Infrared Thermography

( Eunsoo Park ),( Suk-ju Hong ),( Ah-yeong Lee ),( Jongmin Park ),( Byoung-kwan Cho ),( Ghiseok Kim ) 한국농업기계학회 2017 바이오시스템공학 Vol.42 No.3

Purpose: This study was performed to evaluate the feasibility of using an infrared thermography technique for phenotype analysis of pepper seedlings exposed to a low-temperature environment. Methods: We employed an active thermography technique to evaluate the thermal response of pepper seedlings exposed to low-temperature stress. The temperatures of pepper leaves grown in low-temperature conditions (5°C, relative humidity [RH] 50%) for four periods (6, 12, 24, and 48 h) were measured in the experimental setting (23°C, RH 70%) as soon as pepper seedling samples were taken out from the low-temperature environment. We also assessed the visible images of pepper seedling samples that were exposed to low-temperature stress to estimate appearance changes. Results: The greatest appearance change was observed for the low-temperature stressed pepper seedlings that were exposed for 12 h, and the temperature from these pepper seedling leaves was the highest among all samples. In addition, the thermal image of low-temperature stressed pepper seedlings for 6 h exhibited the lowest temperature. Conclusions: We demonstrated that the leaf withering owing to the water deficiency that occurred under low-temperature conditions could induce an increase in temperature in plant leaves using the infrared thermography technique. These results suggested that the time-resolved and averaged thermal signals or temperatures of plants could be significantly associated with the physiological or biochemical characteristics of plants exposed to low-temperature stress.

Phenotyping of Low-Temperature Stressed Pepper Seedlings Using Infrared Thermography

박은수,홍석주,이아영,박종민,조병관,김기석 한국농업기계학회 2017 바이오시스템공학 Vol.42 No.3

Purpose: This study was performed to evaluate the feasibility of using an infrared thermography technique for phenotype analysis of pepper seedlings exposed to a low-temperature environment. Methods: We employed an active thermography technique to evaluate the thermal response of pepper seedlings exposed to low-temperature stress. The temperatures of pepper leaves grown in low-temperature conditions (5°C, relative humidity [RH] 50%) for four periods (6, 12, 24, and 48 h) were measured in the experimental setting (23°C, RH 70%) as soon as pepper seedling samples were taken out from the low-temperature environment. We also assessed the visible images of pepper seedling samples that were exposed to low-temperature stress to estimate appearance changes. Results: The greatest appearance change was observed for the low-temperature stressed pepper seedlings that were exposed for 12 h, and the temperature from these pepper seedling leaves was the highest among all samples. In addition, the thermal image of low-temperature stressed pepper seedlings for 6 h exhibited the lowest temperature. Conclusions: We demonstrated that the leaf withering owing to the water deficiency that occurred under low-temperature conditions could induce an increase in temperature in plant leaves using the infrared thermography technique. These results suggested that the time-resolved and averaged thermal signals or temperatures of plants could be significantly associated with the physiological or biochemical characteristics of plants exposed to low-temperature stress.

Development of a Seedling Screening Method for Low-Temperature Tolerance in Pumpkin (Cucurbita moschata) and Selection of the Tolerant Resources for Rootstock of Cucumber

유채린,Hemasundar Alavilli,송기환 한국육종학회 2022 Plant Breeding and Biotechnology Vol.10 No.2

Pumpkin (Cucurbita moschata) has been increasingly used as bloomless rootstock for cucumber (Cucumis sativus), butit is sensitive to low-temperature, which is the major bottleneck for winter cultivation. Hence, to develop low-temperature tolerantrootstock varieties, it is needed to identify tolerant germplasm from a wide range of genetic resources. For this, we developed a selectioncriterion for a quick assessment of low-temperature tolerance in pumpkin germplasms from different geographical origins. Weconsidered various indexes for the fast evaluation of low-temperature tolerance, including seedling developmental stage, type ofseedling (excised or non-excised), growth space, etc. Under the testing condition (17℃/7℃, 8 hours light/16 hours dark, 150 μmol m-2s-1light intensity), we found a correlation (r=0.71*) in root growth between 3 weeks-cultured excised seedlings and 6 weeks-culturednon-excised seedlings. Therefore, we extrapolate that excised cotyledonary stage seedling treated for 3 weeks is sufficient todifferentiate the tolerant germplasms. Using this screening method, we identified the “S81015” could prevail low-temperature stress. Further, we tested grafting compatibility and growth of grafted cucumbers under the low-temperature condition to assess the effect ofrootstock and identify low-temperature tolerant and grafting-compatible rootstock germplasm. Upon grafting, we found a highcorrelation (r=0.97**) between the root fresh weight of 6 weeks-cultured non-excised seedlings and the shoot fresh weight of thegrafted cucumbers. In summary, we could identify the low-temperature tolerant pumpkin germplasms by screening at the earlydevelopmental stage. Further, as a rootstock, the tolerant pumpkins also fortified the low-temperature tolerance of grafted cucumbers.

Mapping quantitative trait loci controlling low-temperature germinability in rice

Nguyen Hoang Nam,In-Kyu Park,Sang-Min Yeo,Yeo-Tae Yun,Sang-Nag Ahn 충남대학교 농업과학연구소 2012 농업과학연구 Vol.39 No.4

Low-temperature germination is one of the major determinants for stable stand establishment in the rice direct seeding method in temperate regions and at high altitude areas. Quantitative trait loci (QTL) controlling low-temperature germinability in rice were identified using 96 introgression lines (ILs) derived from a cross between Oryza rufipogon and the Korean japonica cultivar, ‘Hwaseongbyeo’. The germination rate at 15℃ was measured to represent low-temperature germination and used for QTL analysis. The germination rate at 15℃ for 7 days of Oryza rufipogon and Hwaseongbyeo was 93.3 and 28.7%, respectively, and that of progenies ranged from 0 to 48%. A linkage map was constructed using 135 simple sequence repeat (SSR) markers. Five putative QTLs associated with low-temperature germination were detected on chromosomes 1, 3, 4, 10 and 11. The QTL, qltg10 on chromosome 10 accounted for 19.2% of the total phenotypic variation for low-temperature germinability. Four additional QTL, accounted for 10.4 - 15.1% of the total phenotypic variation. The O. rufipogon alleles in all detected QTLs loci increased the low-temperature germination rate. No QTL associated with low temperature germinability has been detected near the qltg10 QTL in this study suggesting that qltg10 is a new QTL. The locus, qltg10 is of particular interest because of its independence from undesirable height and maturity effects. The DNA markers linked to the QTL for low temperature germinability would be useful in selecting lines with enhanced low temperature germinability in rice breeding program.