• Applied Biological Chemistry
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• v.40 no.1
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• pp.43-47
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• 1997

The weight ratio of the seed in jujube averaged to 19.1%. The chemical components of dried pitted-jujube were moisture 20.4%, protein 5.3%, fat 1.3%, ash 2.7%, fiber 4.4% and nitrogen-free extract 65.9%. Alcohol insoluble solid content of dried pitted-jujube was 17.4%, in which ammonium oxalate-soluble pectin was 3.7%, water-soluble pectin 3.0%, hydrochloric acid-soluble pectin 1.0%, and sodium hydroxide-soluble pectin 1.0%. Jujube contained sucrose, glucose and fructose as free sugar. The sugars of dried pitted-jujube was composed of sucrose 48.1%, fructose 18.7%, and glucose 11.3%. Drying experiments of pitted-jujube and unpitted-jujube were carried out. Moisture content and brix of dried pitted-jujube were reached at that of dried unpitted-jujube(11%, 78 brix in 48 hours of dry) in 11 hours of drying. And this means that dried pitted-jujube dried 4 times faster than dried unpitted-jujube. The extracts of dried pitted-jujube and dried unpitted-jujube were examinet according to the amount of water added and the extraction time. The brix of dried pitted-jujube extract for 30 min is similar to that of dried unpitted-jujube extract for 150 min. The brix of the extracts did not increase after 150 min extraction. As to the color of extract, 'L' value was higher in dried unpitted-be, while 'a' and 'b' values were higher in dried pitted-jujube.

• Journal of the Korean institute of surface engineering
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• v.4 no.1
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• pp.5-15
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• 1971

"Rapid Determination of Boric Acid in Nickel Plating Solution" by the addition of Na$_2$C$_2$O$_4$ and thus preventing the precipitation of i(OH)$_2$ during titiration , has previously been reported. In this paper, the exact amount of glycerine and the complexing possibility of oxalate with nickel has been determined by measn of conductivity titrations. This experimental work has been supported by the mathematical application of the Debye-Huckel and mass action equitions as well as statistical analysis. The results were ; (1) Fro determining boric acid in nickel plating solution, 20 ml of 400ml/ι glycerine was sufficient, since 97% of the H$_3$BO$_3$ was dissoicated by this addition. (2) In the absence of Na$_2$C$_2$O$_4$ the continious precipitation of Ni(OH)$_2$ during titration with NaOH even past end -point for boric acid determination resulted in considerable anlaytical error. (3) In the presence of Na$_2$C$_2$O$_4$ during titration , Ni++ combined with C$_2$O$_4$-to form NiC$_2$O$_4$. The solution with this precititate of very fine, colloidal , trantsparent particles, remained quite clear for approximately 2 hours. Therefore it was shown that the presence of Na$_2$C$_2$O$_4$ prevents the formation of gross Ni(OH)$_2$ precititation by forming NiC$_2$O$_4$ instead of a complex salt with Ni++ , which did not interfere with the visible determination of the end point for boric acid with NaOH titation. This observous may be interpreted in the light of the previously published solubility ratio for NiC$_2$O$_4$ and Ni(OH)$_2$, 0.3mg/100g H$_2$O(25$^{\circ}C$), respectively. Precipitation of the less soluble , albeit transparent salt, NiC$_2$O$_4$ precluded therefore the precipitation of the Ni(OH)$_2$ salt.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.91-96
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• 2004

Accumulation of nitrate in edible crops is undesirable due to potential risks to human health. Since nitrate has a role in the osmotic regulation of plants, salt accumulation in soil is expected to stimulate nitrate accumulation in plants. Lettuce (Lactuca sativa L.) was grown in soils of different salinities, 9.69 and $4.49dS\;m^{-1}$, in a greenhouse, and the effect of soil salinity on nitrate accumulation in lettuce was investigated. Content of nitrate in the lettuce increased significantly as soil salinity increased under low light intensity and ample supply of nitrate in root media. Soluble sugar and oxalate contents in lettuce were also significantly higher in the soil of higher salinity. Phosphate, Cl, and $SO_4$ contents in lettuce were not significantly different in soils of different salinities. Among the cations, K content in lettuce was significantly higher in the soil of higher salinity, but Na, Ca, and Mg comtents were not much influenced. Comparing to the lettuce grown in low salinity soil, although the growth of lettuce was decreased by 9% in the soil of higher salinity, nitrate accumulation in the lettuce was increased by 18.6%. These results indicate that higher nitrate content in lettuce of higher salinity soil is a positive accumulation to adapt to the water stress condition. The nitrate accumulation of vegetables grown in plastic film houses is known to be due to the heavy fertilization and low light intensity, but salt accumulation in the soil, which can lower soil water potential, is expected to stimulate the nitrate accumulation further.

• Food Science and Preservation
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• v.13 no.2
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• pp.204-210
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• 2006

To accept basic data of utilizing of citron (Citrus junos) as a raw material of industrial produce, major chemical components of citron were investigated. Weight ration of poet flesh md seed of citron were 44.7, 42.9 and 12.4%, respectively. Comparing proximate composition of peel and flesh of citron, peel showed higher in crude protein crude fat and crude ash than flesh but lower in moisture, carbohydrate and soluble solid. The major free sugars of citron were fructose, glucose and sucrose. Peel contained higher in sucrose than flesh, but lower in fructose and glucose. The content of K md P were 309 and 15.9 mg% in peel and 175 and 22.4 mg% in fresh, respectively. The main organic acids of citron were citrate, malate and oxalate. Total organic acid content of flesh (6.6%) was higher than that of peel (4.6%). Total amino acid content of peel and flesh were 671.9 and 315.7 mg%, respectively. Free amino acid content of peel and flesh were 324.3 and 280.7 mg%, respectively, and the major ones were proline, serine, glutamic acid, aspartic acid, and histidine. Total 49 volatile compounds were detected and 26 of these ones were identified in cion. The major volatile component of citron was limonene, which consists of 80% among the total volatiles in peel by all extract methods.