• Journal of Bio-Environment Control
• /
• v.29 no.4
• /
• pp.388-398
• /
• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.2
• /
• pp.258-264
• /
• 2014

This study investigated the effects of die temperature and repeated extrusion on the chemical components and antioxidant properties of extruded white ginseng (EWG). Die temperature was adjusted to 100, 120, and followed by repeated extrusion under the same conditions with corresponding samples. Secondary extruded white ginseng (SEWG) at a die temperature of $120^{\circ}C$ had the highest acidic polysaccharide content of all extrudates. Increasing die temperature and repeated extrusion both increased crude saponin content of the extrudate. Ginsenoside Rh1 was detected in the EWG ($140^{\circ}C$) and SEWGs, whereas ginsenosides Rg3s and Rg3r were only detected in SEWG ($140^{\circ}C$). The highest total phenolic content, DPPH radical scavenging activity, and reducing power obtained from SEWG ($140^{\circ}C$) were $8.55{\pm}0.03$ mg/g, $72.05{\pm}0.63%$, and $0.80{\pm}0.004$, respectively. In conclusion, repeated extrusion increases antioxidant activity and crude saponin contents for the development of improved ginseng products.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.11
• /
• pp.1485-1490
• /
• 2008

The effects of $\gamma$-irradiation on antioxidant and physicochemical properties of powder and 70% fermented ethanol extracts of Ishige okamurai (I. okamurai) were investigated. In case of powder, although yields were increased, there were no significant changes in total phenolic compounds (TPC) and 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect by $\gamma$-irradiation at 3, 7, and 20 kGy. In case of 70% fermented ethanol extracts, the results of TPC and DPPH radical scavenging effects showed no significant changes. However, antioxidant index increased in the 20 kGy irradiated I. okamurai extracts and decreased in 3 kGy irradiated ones. The optical density value of UV spectrum at 427 nm significantly decreased depending on increasing irradiation dosage. In conclusion, irradiated extracts of I. okamurai can be applied to the food industry due to irradiation stability on antioxidant properties. Also, irradiated extracts can be more useful for food processing as a result of a decrease of extracts color by irradiation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.4
• /
• pp.446-450
• /
• 2005

The biological activity of water and ethanol extracts from Chamomaile for functional food source were examined. Total phenol contents in the $60\%$ ethanol extracts $(24.98\pm0.20\;mg/g)$ from Chamomaile leaf was higher than those of water extracts $(23.64\pm0.35\;mg/g)$ The major phenolic compound by HPLC were rosemarinic acid and Quercetin. $60\%$ ethanol extracts had higher content of these phenolics than water extacts. Electron donating ability showed $91.05\%$ in the water extracts and $95.49\%$ in the $60\%$ ethanol extracts. Antioxidant protection factor (PF) showed $0.71\pm0.02 $ in the water extracts and $1.48\pm0.03 $ in the $60\%$ ethanol extracts. The water extracts of Chamomaile leaves did not have antimicrobial activity against H. pylori, but the $60\%$ ethanol extracts revealed the slight antimicrobial activity as 9.42 mm of clear zone. Angiotensin converting enzyme inhibition was $57.98\%$ in water extracts and $91.36\%$ in $60\%$ ethanol extracts. Xanthine oxidase activity was $73.48\%$ in water extracts and $81.96\%$ in $60\%$ ethanol extracts. The results suggest that Chamomailes extract may be useful as potential source as antioxidant, angiotensin converting enzyme and xanthine oxidase inhibitors.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.2
• /
• pp.139-144
• /
• 2006

In this study, we investigated the antioxidant activity of solvent extracts from Sargassum thunbergii by measuring electron-donating ability (EDA), nitrite- scavenging ability, superoxide dismutase (SOD)-like activity, reducing power and antioxidant activity in $\beta-carotene-linoleate$ model system. Total phenolic compound contents of chloroform and methanol extracts from Sargassum thunbergii were $22.5{\pm}0.8$ mg/100 mL and $20.1{\pm}0.6$ mg/100 mL, respectively. The EDA were proportionally increased with concentration of the extracts except hexane extract. The EDAs were $70.4\%\;and\;63.2\%$ in methanol and water at concentration of $1000{\mu}g/mL$, respectively. The nitrite-scavenging ability of methanol extract (pH 2.5, $1000{\mu}g/mL$) was $89.4{\pm}0.9\%$ that was higher than those of other extracts. SOD-like ability of chloroform extract was stronger than other extracts. Reducing power of chloroform extracts at $1000{\mu}g/mL$ were 0.75 as O.D. value of 700 nm and antioxidant activities measured with $\beta-carotene-linoleate$ model system were in order of methanol $(78.4\%)>BHT\;(72.1\%)>chloroform\;(62.2\%)>water\;(51.4\%)>hexane\;(43.2\%)$. These results indicated that methanol extract from Sargassum thunbergii showed the highest activities on the EDA, nitrate- scavenging ability and antioxidant activities while the chloroform extract had the highest effect on the SOD-like activity and reducing power.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.9
• /
• pp.1297-1301
• /
• 2005

This study was carried to develop the new functional food material by exploring natural antioxidant substances of Crotalaria sessiflora L. We compared antioxidative activity of potential antioxidant substances extracted from Crotalaria sessiflora L. The order of extract yield of Crotalaria sessiflora L. were stem > loaves > seed > root. Antioxidative activities of Crotalaria sessiflora L. were measured by total polyphenol contents EDA (electron donating activity), SOD (superoxide dismutase) -like activity, hydroxyl radical scavenging ability and hydrogen peroxide radical scavenging ability. Total polyphenol acid content was much higher in leaves Ex than other extracts. And leaves Ex showed the most excellent antioxidative activity ($86.27\%$) in terms of SOD-like activity. The EDA was ordered loaves Ex > stem Ex > seed Ex > root Ex. Hydroxy radical scavenging ability was the most effective in loaves Ex, and hydorogen Peroxide radical scavenging ability was the highest in seed Ex. Therefore we could be certain that leaves Ex was the most effective in antioxidative activity from Crotalaria sessiflora L.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.3
• /
• pp.315-320
• /
• 2006

For the purpose of developing natural antioxidant, the antioxidative and antimicrobial activities of phenolics isolated from spices were determined. The total phenolics contents of spices were more than 20 mg/g in water and 60% ethanol extracts of all spice, oregano and sage. Electron donating ability assay showed high inhibition rate in water extracts of all spice, nutmeg, white pepper, oregano and sage and 60% ethanol extracts of oregano and nutmeg. Antioxidant protection factor (PF) was higher than 1.2 in 60% ethanol extracts of sage, all spice and oregano and water extracts of sage. The 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radical decolorization (ABTS) was inhibited by more than 90% by water and 60% ethanol extracts of all spice and oregano. TBARS (thiobarbituric acid reactive substances) were $0.7{\mu}M$ in the control and $0.2{\mu}M$ in water and 60% ethanol extracts the each spices. The water extracts of each spices did not have antimicrobial activity against H. pylori; however, the 60% ethanol extracts from oregano revealed the high antimicrobial activity as clear zone of 10 mm and inhibition rate of 77.2% with $200{\mu}g/mL$ of phenolics content. The result suggests that spices extract may be useful as potential sources of anti-Helicobacter pylori, antioxidant.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.3
• /
• pp.271-277
• /
• 2006

A mechanically pressed juice of Bokbunja (Rubus coreanus Miq.) extract was prepared using 70% ethanol solution. The extract was subjected to gamma-irradiation treatment (20 kGy) and investigated for its change of color and biological activities. Hunter $L^*$ values of the irradiated Bokbunja extract were increased in comparison with the non-irradiated extracts, and the $a^*\;and\;b^*$values decreased by the irradiation treatment. The content of the total phenolic compounds in the non-irradiated and irradiated extracts were 58.4 and 56.5 mg/g, respectively. The 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activities of non-irradiated and irradiated extracts at a 250 ppm level were 80% and 79%, respectively. Lipid oxidation was retarded by addition of Bokbunja powder. Nitrite scavenging activity was the highest in the Bokbunja powder at pH 1.2 and the effect was not changed by irradiation. The Bokbunja powder showed antimicrobial activity against Salmonella Typhimurium and Bacillus cereus. However, irradiation of Bokbunja did not affect any physiological functions (p>0.05). A Salmonella mutagenicity assay indicated that the irradiated Bokbunja extract did not show any mutagenicity. Therefore, Bokbunja extract could be used in various applications as a functional material, such as ingredients of food and cosmetic, compositions with functions.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.4
• /
• pp.247-256
• /
• 2013

In this study, alginate beads containing birnessite (Bir-AB), a highly reactive oxidative catalyst for the transformation of phenolic compounds, was prepared and its 1-naphthol (1-NP) removal efficiency was investigated in a batch test. Based on scanning electron microscopy image, it can be inferred that the alginate gel cluster acts as a bridge which bind the birnessite particles together. Kinetic experiment with Bir-AB of different mixing ratios of birnessite to alginate (Bir : AG=0.25 : 1~1 : 1 w/w) indicate that pseudo-first order kinetic constants, $k(hr^{-1})$ for the 1-NP removals increased about 1.5 times when the birnessite mixing ratio was doubled. The removals of 1-NP was found to be dependent on solution pH and the pesudo-first order rate constants were increased from 0.331 $hr^{-1}$ at pH 10 to 0.661 $hr^{-1}$ at pH 4. The analysis of total organic carbon for the reaction solutions showed that a higher removal of dissolved organic carbon was achieved with Bir-AB as compared to birnessite. HPLC chromatographic analysis of the methanol extract after reaction of 1-NP with Bir-AB suggest that the reaction products could be removed through incorporation into the aliginate beads as a bound residue. Mn ions produced from the oxidative transformation of 1-NP by birnessite were also removed by sorption to Bir-AB. The Bir-AB was recovered quantitatively by simple filtration and was reused twice without significant loss of the initial reactivity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.3
• /
• pp.282-292
• /
• 2014

This study investigated the changes of antioxidant compounds and antioxidant activity of foxtail millet (FM) and proso millet (PM) by drainage methods in poorly drained sloping paddy field. The experimented soils in this study were very poorly drained (VPDP) and imperfectly drained paddy soil (IDP). Two drainage methods namely under pipe drainage (UPD) and open ditch (ODD) were installed within 1-m position at the lower edge of the upper paddy fields. The soil moisture contents of UPD and ODD on VPDP were $18.52{\pm}4.58$ and $19.01{\pm}4.25%$, and IDP were $14.87{\pm}4.82$ and $18.64{\pm}3.85%$, respectively. Generally, crop yields, proximate and minerals composition of FM and PM showed significant differences by drainage methods. The total polyphenol, flavonoid and tannin contents, and radical scavenging activity of the ethanolic extracts of FM and PM showed significant differences by drainage methods. The total polyphenol content of FM and PM by drainage methods was 1.69~2.30 and 1.18~1.35 mg GAE/g, total flavonoid content was 0.31~0.76 and 0.27~0.41 mg CE/g, and total tannin content was 0.36~0.54 and 0.21~0.28 mg TAE/g, respectively. The DPPH radical scavenging activity of FM and PM was 39.53~59.81 and 27.91~40.25 mg TE/100 g, and ABTS radical scavenging activity was 113.59~152.10 and 61.38~79.19 mg TE/100 g, respectively. The antioxidant compounds and radical scavenging activity of FM and PM by drainage methods were frequently affected soil water.