• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.1
• /
• pp.78-83
• /
• 2013

The excessive and indiscriminate use of chemical fertilizers in the past has brought serious soil and other environmental problems so alternatives over this agrochemical are being searched. Our study focuses on the effects of expanded rice hull inoculated with selected beneficial microorganisms on growth (through agronomic characters), yield and yield components, and grain quality indices of rice. Results showed that favorable effects of different expanded rice hull preparations were not readily apparent at vegetative stage and only treatments with supplemental chemical fertilizer application were comparable with the conventional practice. Expanded rice hull combined with 50% rate of chemical fertilizer exhibited a significantly higher yield (6,471 kg $ha^{-1}$) over conventional practice (5,719 kg $ha^{-1}$). Good milling quality indices were observed in treatments having 50% chemical fertilizers plus alternatives from expanded rice hull. Finally, we demonstrated that chemical fertilizer rate can potentially be reduced into 50% if combined with expanded rice hull, and show even better output than chemical fertilizer alone.

• Korean journal of food and cookery science
• /
• v.20 no.5
• /
• pp.462-467
• /
• 2004

This study was carried out to improve the qualities and extend the shelf life of Yukwa and Salyeotgangjung, traditional Korean cookies, using fine hot salt instead of oil as the popping medium. The Yukwa and Salyeotgangjung that had been popped using fine salt were stored at 25\ulcornerfor one or two months, and then compared their sensory evaluation, lipid contents and acid and peroxide values with those popped in oil. In the sensory test, the Yukwa base and popped rice expanded in the salts and stored for one month were preferred to those expanded in oil with regard to flavor and overall acceptability. With respect to the whiteness, off-flavor, and crispness, these properties those expanded in salt had stronger whiteness and crispness but a weaker off-flavor compared to those expanded in oil. The lipid contents of the Yukwa base and popped rice expanded in oil were 37.73 and 49.65%, respectively, which were significantly higher than in those expanded in salts (0.10 and 0.53%, respectively). The acid and peroxide values were larger in those expanded oil than in salts after 8 weeks storage. In view of the above results, the conclusion was reached that the Yukwa base and popped rice expanded in salts were less likely to provide a calorie intake and to become rancid over a long storage time.

• Journal of the Korean Society of Food Culture
• /
• v.16 no.4
• /
• pp.323-329
• /
• 2001

This study was carried out to observe the character change of expanded rice grain for Salyeotgangjung at various gelatinization methods. The expansion and structure change of rice grain was different at conditions of heating methods and gelatinization, respectively. The boiling showed good expansion compared to other heating methods by electric rice-cooker, pressure cooker, and steam cooker. There was not difference in expansion of rice grain between the boiling and the boiling after soaking. Rice grain did greatly expand as the boiling time was extended. But the quality for Salyeotgangjung would be not good because of crack of expanded rice grain surface when the boiling time was too long.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.1
• /
• pp.55-59
• /
• 2005

Rice farmers can save labor and expenses by using expanded rice husk (ERH) as a seedling medium since ERH is lighter and cheaper than other commercial seedling media (CSM). This study was carried out to develop a method for rice seedling cultivation using ERH as a seedling medium. It is suggested that a mixture of $60\%$ of ERH and $40\%$ of a CSM could be used as a seedling medium; the planting densities would be 240g per tray for infant seedlings and 200 g for young seedlings; and nitrogen (N) would be applied at a rate of 1g per tray for infant seedlings prior to planting and 2g per tray for young seedlings with division. Great care should be taken to use $CO(NH_2)_2$ as an N-source fertilizer. These results would lay a foundation for the rice seedling cultivation with ERH as a medium.

• Journal of Bio-Environment Control
• /
• v.10 no.2
• /
• pp.95-100
• /
• 2001

In countries that consumes rice as a main staple, rice hulls are natural resources composed of a large amount of organic compounds and high uniformity in size. Rice hulls are expanded to get rid of a defect in untreated rice hulls and to be used as a hydroponic substrate. Research on rice hulls is continuing for the agricultural application. This research was conducted to stabilize rhizosphere pH of the expanded rice hull substrates because of high pH caused by repeated use in ERH(expanded ride hull) substrates and without increasing the cost of developing new substrates. Sphagnum peatmoss (pH 3.0-4.0) wee mixed with the expanded rice hull substrate in the ratio of 10% (v/v), and this ratio kept the pH range of 6.0 to 6.5 in the root area of tomato plants during growth and at the time of harvest of tomato fruits. Also absorbtion of nutrients was highly increased. The yield increased from 1,051 to 1,266 kg per tomato plant which were harvested by two clusters.

• Journal of Bio-Environment Control
• /
• v.9 no.2
• /
• pp.73-78
• /
• 2000

This study was carried out to investigate appropriate processing conditions for expanded rice hulls to be used as a medium material in nutrient cultures. The water holding capacity of expanded rice hulls produced by using a domestic grinder with 8 mm gap and 3 mm cutter height was 271.0, and the bulk density and CEC were 0.19g·m-3 and 37.0 cmol·kg-1, respectively. These values are higher than those of perilte. However, geometric mean diameter (GMD) of expanded rice hulls was 1.01mm which was smaller than that of perlite, indicating unfavorable porosity. After supplying nutrient solution, the faster water percolation in expanded rice than perlite required more frequent water supply. There was no significant difference in tomato fruit yield between expanded rice hull and perlite. The pH increase and the lack of nitrogen in early stage of culture are to be solved in the future.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.2
• /
• pp.128-135
• /
• 2013

The use of agricultural by-products as alternative nutrient sources in crop production had gained popularity in order to reducing the rate of chemical fertilizer application in the field. This study was conducted to determine whether the application of rice milling by-products treated with yeast inoculants could substitute, or reduce the rate of chemical fertilizer application. The results of agronomic measurements showed that the effect of incorporated materials was not immediate, as compared to 100% chemical fertilizer application. However, grain yield and quality was either the same or greater than 100% chemical fertilizer application. It was found out that expanded rice hull (treated with yeast or not) could reduce the rate of applying chemical fertilizers by half. Also, yeast treatment was only favorable only to expanded rice hull and not with rice bran, and was already found to be a potential material in reducing chemical fertilizer application in rice production.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.50 no.2
• /
• pp.120-124
• /
• 2005

Expanded rice husk (ERR) is different from commercial rice seedling media in chemical and physical properties such as pH, permeability, and water content. This study was conducted to test a possibility of improving rice seedling growth by improving the texture of ERR as a rice seedling medium. The seedling media used were a commercial seedling medium (CSM), rice husk, and ERR 1, 2, 3, and 4 with different expansion degrees. The pH of the ERHs ranged from 6.3 to 6.8. As the expansion rate increased, ERR particle sizes decreased, and water permeability and absorption rates improved. No significant differences in shoot dry weight and rate of maturity were found among the seedlings cultivated in the different ERH media. However, the mat formation of seedling roots became loose as the expansion rates were decreased. Further studies are necessary to determine the cause of poor root growth in ERH media.

• Journal of Bio-Environment Control
• /
• v.10 no.2
• /
• pp.106-110
• /
• 2001

In an effort to evaluate the economic value and durability of the expanded rice hull as substrates, changes in the physical and chemical properties of material and plant growth in that substrate were studied. Using and electron microscope, the structure of used and new expanded rice hull substrate was examined. Considerable decomposition was found in the substrate which had been used one to three times. Compactness and lowered porosity in the used substrates were probably caused by decomposition. The results of cation analysis showed the possible destruction of cell wall of rice hulls. Abundant $Ca^{2+}$ in the substrates used for two to three times also indicated the possibility of decomposition. In tomato yield comparison, 15.2% more yield of tomato fruit in a new substrates indicated the negative effects of decomposition of one-time used substrates. Yield decreased in the substrates used for three times. if perlite substrates is used for three years before renewal and the cost of the perlite renewal is counted. 65.3% saving in the cost will be realized with the use of an expanded rice hull substrate. Another positive effect of the expanded rice hull substrate is the decrease of environmental contamination.n.

• Korean journal of food and cookery science
• /
• v.19 no.6
• /
• pp.729-736
• /
• 2003

This study was performed to improve the quality and extend the shelf life of Yukwa and Salyeotgangjung, traditional Korean cookies, by using fine hot salt instead of oil as the popping medium. Yukwa and Salyeotgangjung were popped with fine salt, and the size, sensory evaluation, color values and textural properties were then compared with those popped in oil. The results showed that the Yukwa base with salt was popped the most at 140C and the rice was popped at 240C. The Yukwa base in salts was smaller in size and larger in density than in oil but the popped rice in salts had a similar size and a smaller density than that popped in oil. In the sensory test, the Yukwa base and popped rice expanded in the salts were preferred to those popped in oil but there was little difference in only popped rice. In terms of color, there was a difference between those popped in salt and in oil. In terms of texture, only popped rice expanded in the salts was harder than in oil, and the Yukwa popped in oil was more cohesive than in the salts. In brittleness, there were no differences between in salt and in oil.