• Journal of Ecology and Environment
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• v.44 no.4
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• pp.229-240
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• 2020

Background: Genus Quercus is a successful group that has occupied the largest area of forest around the world including South Korea. The acorns are an important food source for both wild animals and humans. Although the reproductive characteristics of this genus are highly variable, it had been rarely studied in South Korea. Therefore, in Seoraksan and Odaesan National Parks (i) we measured the acorn production of Quercus mongolica, an overwhelmingly dominant species in South Korea, for 3 years (2017-2019), (ii) evaluated the spatial-temporal variation of acorn production, and (iii) analyzed the effects of oak- and site-related variables on the acorn production. Results: The annual acorn production of Q. mongolica increased 36 times from 1.2 g m-2 in 2017 to 43.2 g m-2 in 2018, and decreased to 16.7 g m-2 in 2019, resulting in an annual coefficient of variation of 104%. The coefficient of spatial variation was high and reached a maximum of 142%, and the tree size was the greatest influencing factor. That is, with an increase in tree size, acorn production increased significantly (2018 F = 16.3, p < 0.001; 2019 F = 8.2, p < 0.01). Elevation and slope also significantly affected the production in 2019. However, since elevation and tree size showed a positive correlation (r = 0.517, p < 0.001), the increase in acorn production with increasing elevation was possibly due to the effect of tree size. The acorn production of Odaesan for 3 years was 2.2 times greater than that of Seoraksan. This was presumed that there are more distribution of thick oak trees and more favorable site conditions such as deep soil A-layer depth, high organic matter, and slower slopes. Conclusion: As reported for other species of the genus Quercus, the acorn production of Q. mongolica showed large spatial and annual variations. The temporal variability was presumed to be a weather-influenced masting, while the spatial variability was mainly caused by oak tree size.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.177-184
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• 2013

This study was conducted to investigate the effects of acorn (fruits of Quercus species) powder on the antioxidant activity and quality characteristics of cookies. Cookies were prepared with different amounts (0, 0.5, 1, 3 and 5% to the flour quantity) of acorn powder. The antioxidant activity was estimated by DPPH free radical scavenging activity and the total phenolic acid content in acorn powder and cookies. For analyzing quality characteristics, bulk density, pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations were measured. The moisture contents, a values, total phenolic acid content and DPPH free radical scavenging activity of cookies significantly increased with increasing acorn powder (p<0.001), while the pH of the dough, L values and b values of the cookies significantly decreased with increasing acorn powder (p<0.001). The consumer acceptability score for the 3% acorn cookie groups ranked significantly (p<0.05) higher than the other groups in overall preference, appearance, flavor, taste and color. From these results, we suggest that acorn is a good ingredient for increasing the consumer acceptability and the functionality of cookies.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.1-8
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• 2012

Acorn production of some oak species from 2008 to 2010 in Mt. Jiri national park(Pia, Bitjeom, Jangdang, Baemsa, Hansin, and Chilsun) was measured and compared among study area, altitude and aspect because acorns are an important wildlife food resources. Acorns were produced the most in Jangdang and Bitjeom area at year of good fruiting, and those of Bitjeom and Hansin area were produced the most at bad fruiting year. In terms of altitudinal characteristics on acorn production, acorn production in 1000 and 900 m was the most at good fruiting year, and 800 and 900 m at bad fruiting year showed the most production of acorn. Throughout the study period, acorn production on southern slopes was larger than that of northern slopes.

• Journal of Forest and Environmental Science
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• v.32 no.2
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• pp.103-112
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• 2016

To compare seed components of plus trees, seed powder ground after seedcoat removal was analyzed for two oak species, i. e., Quercus monglica (white oak) and Quercus variabilis (red oak), which are typical oak trees in Korea but have different fruiting characteristics. Thus we aimed at analyzing and comparing many ingredients including minerals, sugars, etc. Two species were similar to each other in the content of water, crude ash, crude protein and carbohydrates, but crude lipid content in Q. variabilis was 2.5 times higher than that in Q. mongolica. Crude proteins of Clone 124 was 1.5 times higher than that of Clone 75 in Q. mongolica. Crude lipid content showed the highest value in Clone 0511 of Q. variabilis, and more phosphate and iron was found in Q. monglica than in Q. variabilis. Glucose showed 85.4% and 88.3% on average of the total monosacchrides in two species, and galactose and arabinose were also found. In the content of phosphate, iron, and crude lipid, differences were found between two species and among clones of two species.

• Korean Journal of Food Science and Technology
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• v.8 no.4
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• pp.230-235
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• 1976

The current experiment has been carried out in order to find the chemical and physical properties of three species of the acorn starch. The results of the experiment are as follows. 1. Acorn is made up of 3.5-5.0% of lipid, 7.2-7.7% of protein, 71.6-76.3% of carbohydrate, and 1.9-2.2% of ash. 2. The purifying method of ether treated is better than that of 85% methanol treated for isolating pure starch. 3. Initial gelatinization temperature of the acorn starches ranged from $61-68^{\circ}C$; Quercus crispula Blume was the lowest and Quercus mongolica Fischer was the highest. On viscosity, Quercus mongolica Fischer shows the highest and Quercus crispula Blume shows the lowest. 4. It is estimated that the acorn starch lie halfway between those of the potato starch and the corn starch. By drying at $100^{\circ}C$, the crystal structure is destroyed first in the farther part of the lattice distance.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.47-55
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• 2011

This study investigated mineral element concentrations of acorns in Quercus acutissima and Quercus serrata seed orchard, so that to estimate the variation of these species based on the chemical composition in different clones from plus trees. The acorns were collected from ten clones of each species grown in the same clonal seed orchard. The nutritional concentration of acorns was significantly different between the clones and species. The concentration of nutrient for the whole acorn followed in this general sequence: P > K > Na > Mg > Ca > Mn > Fe > Zn > Cu. The mineral concentrations of acorns in clones of Q. acutissima and Q. serrata contained P (494 to 684 and 541 to 672 mg/100 g), K (114 to 569 and 140 to 251 mg/100 g), Na (57 to 121 and 49 to 85 mg/100 g), Mg (29 to 37 and 26 to 42 mg/100 g), Ca (10 to 53 and 26 to 68 mg/100 g), Mn (0.5 to 3.4 and 1.8 to 4.5 mg/100 g), Fe (0.7 to 1.1 and 0.0 to 2.2 mg/100 g), Zn (0.34 to 0.81 and 0.38 to 0.84 mg/100 g), and Cu (0.13 to 0.40 and 0.09 to 0.34 mg/100 g) respectively. Even though acorns of Q. serrata are smaller in size than Q. acutissima, acorns of Q. serrata contained significantly higher concentration of phosphorus, calcium, iron and manganese than Q. acutissima. Based on the mineral composition of the acorns, this study has shown that the clones of Q. acutissima and Q. serrata have different ability to accumulate mineral nutrients which could indicate the variation of Quercus species in terms of mineral acquisition and accumulation.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.274-279
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• 2011

In order to know the effect of seed size on the early plant life history, we measured the rate of germination, early growth and winter survival of four oak species with different acorn size (large, medium and small). The mean germination rate was higher in the larger seed species ($Q.$ $acutissima$ and ($Q.$ $variabilis$) than those of the smaller seed species ($Q.$ $aliena$ and $Q.$ $serrata$). Within $Q.$ $variabilis$, the germination rate decreased with larger acorn size class but that of rest other species was not significantly affected by the acorn size. The early mean growth rate decreased with acorn size in the order of $Q.$ $acutissima$, $Q.$ $variabilis$, $Q.$ $aliena$ and $Q.$ $serrata$. The early mean growth rate was higher in large or medium size than in small size of $Q.$ $acutissima$ and $Q.$ $variabilis$, but it showed no difference with acorn size in $Q.$ $aliena$ and $Q.$ $serrata$. Survival rate in winter was the highest in the medium acorn size among 4 oak species, the seedling of $Q.$ $serrata$ and $Q.$ $variabilis$ did not survive in both large and small acorn size. These results indicate that seed size influences a different effect on the early plant life history stage.

• Food Science and Preservation
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• v.24 no.1
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• pp.21-26
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• 2017

This study was performed to determine the effects of preconditioning process (Con, roasting; SR, steaming and roasting; HDR, hot air drying and roasting; SHDR, steaming hot air drying and roasting) and roasting on the antioxidant and physicochemical properties of acorn (Quercus species) tea. Each sample was extracted in $95^{\circ}C$ hot water for 5 min. The color values of lightness and yellowness were the highest in HDR, and redness were the highest in the control. The total sugar content was the highest in SHDR. Total polyphenol and total flavonoid contents of HDR tea were higher than those of teas prepared by the different processes. DPPH and ABTS radical scavenging abilities of HDR were 75.66% and 98.16%, respectively, which were higher than those of other teas. In the sensory evaluation, HDR tea was ranked significantly higher than other teas in terms of flavor, taste and overall acceptability. Finally, acorn tea treated with drying was superior to other treatments in antioxidant and quality properties. The result suggests that HDR can be applied to acorn tea to achieve better quality and functionality.

• Journal of Pharmaceutical Investigation
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• v.41 no.6
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• pp.355-362
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• 2011

This work was performed to investigate the protective effect of ethanol extract (AEx) from acorn (Quercus acutissima CARR.) against allergic mediated responses in asthma model cells and mice. The AEx inhibited antigen-stimulated cytokine production such as interleukin (IL)-4, IL-13 and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) and AEx also inhibited intracellular reactive oxygen species (ROS) generation against IgE-mediated allergic response in rat basophilic leukaemia RBL-2H3 cells. The ovalbumin (OVA)-sensitized mice were orally administered with AEx (100 or 300 mg/kg) and authentic tannic acid (75 mg/kg) every day for 15 days. Increased TNF-${\alpha}$ production by OVA-sensitization/challenge was significantly reduced by administration of AEx. The serum triglyceride levels of asthma mice were significantly reduced after feeding for 15 days with tannic acid or AEx. The mice fed with tannic acid or AEx also exhibited a significant reduction in body weights compared to those of asthma control group. The AEx increased the heme oxygenase (HO)-1 mRNA expression in the asthma model mice and showed DPPH radical scavenging activity. These results indicate that AEx protects against IgEmediated allergic and OVA-induced asthmatic responses via direct and indirect antioxidant activities. Reduced triglyceride and body weights may provide additional protective benefits of AEx on allergic asthma.

• The Korean Journal of Ecology
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• v.24 no.6
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• pp.377-380
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• 2001

Herbivory is an important selective forces on plants by reducing the ability of the plant to compete with its neighbors and to produce offspring. Oak nut weevil(Mechoris ursulus Roelofs) females lay eggs in unmatured acorns and cut off the branch of oviposited acorns. To investigate the influences of branch-cutting behavior of oak nut weevils on oak production, we surveyed the horizontal and vertical distribution ranges of damaged oaks and depth of sites of overwintering larvae and quantified the amounts of biomass and acorn removed by the weevils on deciduous oak species. All of the endemic oak species in Korea were damaged by oak nut weevils in all of the study sites including Mt. Halla and Mt. Seorak. The upper limit of vertical distribution of damaged oaks by the weevils raried from 700 m to 900 m. Mostly their larvae were found in soil from 8.1 cm to 10.0 cm depth in winter. Percentage of annual net primary productivity($720g{\cdot}m^{-2}{\cdot}day^{-1}$) of oak species removed by the weevils was about 7%, which is higher than the percentage removed by all the herbivores in typical temperate forest(5%) and equivalent to that by all the herbivores in tropical forest. The predation percentage of annual acorn production by oak nut weevil was 27% in Q. mongolica and 33% in Q. acutissima. This results indicate that the branch-cutting behavior of oak nut weevil may be the most important factor regulating oak population and affecting other predators dependent on acorns.