• Korean Journal of Plant Resources
• /
• v.11 no.2
• /
• pp.152-156
• /
• 1998

This experiment was conducted to investigated the characteristics of grain appearance, chemical components. gelatinization, and palatability of cooked rice on each rachis branches as harvested from the transplanting plot of May 20 and June 5 in each two varieties of early-maturing and late-maturing types. In evaluation of rachis branches, the percentage of ripended grain and 1,000 grain weight were found to be high and heavy at upper part of panicle. The factors influencing palatability such as maximum viscosity and breakdown as gelatinization characteristics, and hardness, apringiness, cohesiveness and chewiness as texture characteristics of cooked rice were found to be high at upper part of panicle , indicating the parlability was favored more at upper part than at lower part of panicle due to the genetics and physiological metabolism of rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.25 no.4
• /
• pp.1-9
• /
• 1980

To determine the optimum harvest time of recent rice varieties from Indica/Japonica remote crosses, leading varieties Suweon 264 and Milyang 23 were tested for the changes in dry matter weight and moisture content of grain, shattering, shelling ratio, milling ratio, and apparant physical quality during grain development at 5 day-intervals from 20 days to 55 days after heading. The results are summarized as follows: 1. Grain weight (dry matter) reached its maximum (physiological maturity) at 30 days after flowering (DAF) in Suweon 264, and at 35 days in Milyang 23, and thereafter it did not change significantly until 55 DAF. 2. Time course of decrease in grain moisture content (Y, %) during maturation (X, DAF) consisted of two linear phases, i.e. a fast and a slow period: Y=68.245-1.33X until 34DAF, and Y=23.025-0.470X until 55DAF after 34DAF in Suweon 264; Y=73.62-1.634X until 24.5DAF, and Y=33.59-0.570X until 55DAF after 24.5DAF in Milyang 23. Two varieties showed the same grain moisture content of 28% (wet basis) at physiological maturity in spite of the distinct differences in the heading date, time of physiological maturity and thereby ripening climate. 3. Force to shatter a grain ranged about 90 to 100g in Milyang 23, and about 200 to 250g in Suweon 264 and in a Japonica variety, Jinheung. The force, however, did not change significantly with harvest time from 35DAF to 50DAF. 4. The changes in the ratios of shelling, milling, broken rice and tinted rice with harvest time were insignificant during a period from 35DAF to 55DAF. However, ratios of green rice and white belly rice decreased significantly with delay in harvest time during 10 days after physiological maturity. 5. The best time of harvest for maximum yield and good quality is thought to be 10 days after physiological maturity, and grain moisture content at this time was about 20% on wet basis.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.2
• /
• pp.174-179
• /
• 2015

This experiment was conducted to determine the optimal harvesting time for barley and wheat grain for the production of fermented grain feeds, and to investigate their fermentation quality according to harvesting time. As a result, grain moisture content was decreased with late harvest, whereas spike weight ratio and 1000 grain weight were increased with prolonged period after heading. Grain yielding was increased with late harvesting time significantly at p<0.05. Crude protein content was increased with late harvesting time, but crude fiber content was decreased. Crude fat and ash content were slightly decreased, but not statistically significant. Comparing the effects of fermentation on feed value of winter cereal grain, the approximate compositions were slightly increased after fermentation, but the difference was not significant. Fermentations resulted in increasing the pH value of winter cereal grain silage with late harvesting time, but decreasing the lactic acid content (p<0.05). No significant difference was found in acetic acid, and butyric acid was not detected. Considering the quantity and quality of fermentation, barley and wheat can be used for winter cereal grain silage when they were harvested at 35 days and 40-45 days after heading, respectively.

• Journal of Sensor Science and Technology
• /
• v.26 no.2
• /
• pp.122-127
• /
• 2017

Graphene grown on copper-foil substrates by chemical vapor deposition (CVD) has been attracting interest for sensor applications due to an extraordinary high surface-to-volume ratio and capability of large-scale device fabrication. However, CVD graphene has a polycrystalline structure and a high density of grain boundaries degrading its electrical properties. Recently, processes such as electropolishing for flattening copper substrate has been applied before growth in order to increase the grain size of graphene. In this study, we systemically analyzed the effects of the process condition of electropolishing copper foil on the quality of CVD graphene. We observed that electropolishing process can reduce surface roughness of copper foil, increase the grain size of CVD graphene, and minimize the density of double-layered graphene regions. However, excessive process time can rather increase the copper foil surface roughness and degrade the quality of CVD graphene layers. This work shows that an optimized electropolishing process on copper substrates is critical to obtain high-quality and uniformity CVD graphene which is essential for practical sensor applications.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.4
• /
• pp.294-302
• /
• 2020

Studies on the occurrence of rice preharvest sprouting (PHS) have primarily focused on temperature and rainfall duration at the time of PHS induction, but average temperature during grain filling can have a great influence on PHS. This study analyzed the effect of average temperature during grain filling on PHS occurrence and subsequent changes in grain quality after PHS. For two consecutive years, average temperature differences during grain filling were produced by varying the transplanting date. Artificial rainfall was treated under identical accumulated temperatures of 1200℃ after heading. It was confirmed that the occurrence of PHS was higher under high average temperature conditions during grain filling. In addition, the degree of grain quality reduction caused by PHS occurred more severely under high temperature conditions during grain filling. In order to reduce the risk of PHS occurrence and subsequent quality damage, it is important to control the planting date to avoid high-temperature conditions during grain filling.

• Journal of Crop Science and Biotechnology
• /
• v.11 no.4
• /
• pp.227-232
• /
• 2008

Drought stress is one of the major abiotic stresses in agriculture worldwide. We report here a proteomic approach to investigate the impact of post-fertilization drought on grain quality in rice seed endosperm (Oryza sativa cv. IR-64). Plants were stressed for 4 days at 3 days before heading. Total proteins of endosperm were extracted and separated by two-dimensional gel electrophoresis. Not many protein spots showed differential accumulation in drought-stressed samples. More than 400 protein spots were reproducibly detected, including three that were up-regulated and five down-regulated. Mass spectrometry analysis and database searching helped us to identify six spots representing different proteins. Functionally, the identified proteins were related to protein synthesis and carbohydrate metabolism, such as Granule-Bound Starch Synthase (GBSS, Wx protein), which is thought to play a very important role in starch biosynthesis and quality, a very crucial factor in determining rice grain quality.

• Journal of Biosystems Engineering
• /
• v.40 no.2
• /
• pp.124-136
• /
• 2015

Purpose: Grain quality is a general concept that covers many characteristics, ranging from physical to biochemical and physiochemical properties. Rice aging during storage is currently a challenge in the rice industry, and is a complicated process involving changes in all of the above properties. Spectroscopic techniques can be used to obtain information on the quality of rice samples in a non-destructive manner. Methods: The objective of this review was to highlight the factors that contribute to rice quality and aging, and to describe various spectroscopic modalities, particularly vibrational and hyperspectral imaging, for the assessment of rice quality. Results: Starch and protein are the main components of the rice endosperm, and are therefore key factors contributing to eating and cooking quality. While the overall starch, protein, and lipid content in the rice grain remains essentially unchanged during storage, structural changes do occur. These changes affect pasting and gel properties, and ultimately the flavor of cooked rice. In addition, grain quality is significantly affected by growing and environmental conditions, such as water availability, temperature, fertilizer application, and salinity stress. These properties can be evaluated using spectroscopic techniques, and rice samples can be discriminated by using multivariate statistical analysis methods. Conclusion: Hyperspectral imaging and vibrational spectroscopy techniques have good potential for determining rice quality properties in a non-invasive manner, i.e., not requiring the introduction of instruments into the rice grain.

• Journal of Life Science
• /
• v.5 no.3
• /
• pp.126-136
• /
• 1995

The studies had been conducted to evaluate the grain processing effects for ruminants on starch digestion, body weight gain and feed efficiency since 1970. This research deals with experimental results on chemical structure, gelatinization, microbial starch digestion in rumen, intestinal starch digestion in rumen, roles of protozoa, intestinal starch digestion of bypass starch, limits to starch digestion in small intestine. The grain processing has different effects on digestion, weight gain and feed efficiency when different grain sources and contents is used, and the quality and quantity of roughage is different. The economical and efficient method of grain processing should be selected considering weight gain and feed efficiency enhancement than digestibility.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.3
• /
• pp.273-281
• /
• 2015

Relationship between grain quality-related traits and daily mean temperature/sunshine hours during grain filling stage was analyzed using eleven high quality rice varieties at 24 experimental sites through eight provinces of Korea in 2013~2014. In the data set pooled across varieties, experimental sites and years, grain quality-related traits such as percentage of head rice (PHR), head rice yield (HRY), protein in milled rice (PRO) and Toyo Mido Meter glossiness value (TGV) were higher at the temperature lower than $22.6^{\circ}C$ for 40 days after flowering (DAF), which was optimum for percentage of grain filling in this study. Optimum sunshine hours for 40 DAF were $6.0{\sim}6.1\;hr\;d^{-1}$when considered PHR, HRY and TGV. PRO was associated with daily mean temperature and sunshine hours for 40 DAF in more varieties than the other traits. PRO was closely correlated with daily mean temperature during early filling stage and sunshine hours during early to mid filling stage, compared to other stages during grain filling. It is concluded that general trend in the variation of grain quality-related traits could be explained by the changes in daily mean temperature and sunshine hours during grain filling. In addition, climate conditions during early grain filling stage played important roles to enhance grain quality.

• Journal of Korean Society on Water Environment
• /
• v.20 no.3
• /
• pp.301-306
• /
• 2004

The present water quality standards for agricultural were established without considering the effects of water quality on the safety, growth, yield and quality of crops. This study was carried out to investigate the effects of irrigation water quality on the growth, yield, and grain quality of rice, and to acquire basic knowledges to set up water quality standards for irrigation. The field and pot experiments were conducted with irrigation water that was previously adjusted four concentrations (control, 5, 10, 20 mg/L) and six concentrations (control, 5, 10, 15, 20, 30 mg/L) by $NH_4NO_3$ solution and replicated three and four times with randomized block design, respectively. The results of this study showed that the inorganic nutrient of rice plant, rice protein contents and number of panicle tended to increase as the T-N concentration in irrigation water was increased. In addition, grain yield at T-N 10 mg/L and 20mg/L were significantly higher than the control at the field experiment. From the pot experiment at T-N 30 mg/L, the percentage of head rice was slightly lower due to the increase of green kernel and white belly/core kernel.