• The Korean Journal of Rheology
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• v.10 no.1
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• pp.7-13
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• 1998

중량 평균 분자량이 1.22$\times$106이고 다분산도가 8.90이며 수분과 아밀로오스 함량이 각각 9.35%, 27%인 도토리 전분에 sucrose를 첨가하여 동적 유변학적 특성에 대한 온도와 농도의존성을 고찰하였다. AS(acorn starch)-sucrose 계의 점도는 전단속도가 증가하면 감 소하는 전단담화 현상을 나타내며 sucrose 농도가 증가할수록 점도가 증가하였고, Casson 식에 의해 얻어진 항복치는 sucrose 농도가 증가하면 증가하였다. 저장영률과 손실영률은 sucrose 농도가 증가하면 단일하게 증가하였고 손실 탄성률은 온도가 증가하면 감소하였다. DSC 측정자료를 zipper model에 적용시켜 본 결과 sucrose 농도가 증가할수록 zipper의 수 와 junc-tion zone의 수는 증가했으며 크기는 감소하였다. Sucrose는 전분과 수소결합을 형 성하여 용액내에서 가소제처럼 거동함을 알수있었다.

• Korean journal of food and cookery science
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• v.16 no.4
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• pp.342-351
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• 2000

This study aimed for exploring the best recipe of Sangjabyung to increase its utility value and to develop traditional Korean rice cake industry for next generation. The best recipe was determined after several tests such as sensory evaluation and mechanical measurements for texture, moisture content, and colorimetry. The samples prepared with 5% of acorn starch with honey showed the best scores in sensory evaluation for color and flavor, 5% of acorn powder with sugar for grain, 15% of acorn powder with sugar for moistness and chewiness, 15% of starch with honey for sweetness, and non-glutinous rice flour mixed with 10% of acorn powder and sugar for overall quality. Every item except for flavor was significantly different from that of control (P<0.05). The highest score for springiness was obtained from the samples prepared with 10% of acorn starch with sugar, cohesiveness with 5% of acorn starch with sugar, chewiness with 15% of acorn starch with honey, gumminess with 15% of acorn starch with honey, adhesiveness with 5% of acorn starch with honey, and hardness with 15% of acorn starch with honey. All items were significantly different from that of control (P<0.05). The overall quality of sensory evaluation was correlated with moistness(P<0.05), springiness, cohesiveness(P<0.01), and adhesiveness(P<0.01) in mechanical test. Moisture contents of rice flour, acorn starch, and acorn powder were 32.93%, 8.52%, and 13.26%, respectively. The desirable moisture content in Sangiabyung was 44.11% in the case of using rice flour with acorn starch or 44.33% for rice flour with acorn powder. As a result of colorimetry, the best L, a, and b values were obtained from the rice cakes with 5% acorn starch and oligosaccharides, with 15% of acorn powder and sugar, and with 15% of acorn starch with oligosaccharides, respectively. Overall. the most desirable recipe for Sangjabyung was determined as rice flour 315 g, acorn starch or acorn powder 35 g, sugar 60 g, salt 3.5 g, and water 130 ml.

• Korean journal of food and cookery science
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• v.8 no.1
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• pp.9-14
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• 1992

The morphological properties of acorn starch granules and starch gels were examined with scanning electron microscope and X-ray diffractometer. The shape of acorn starch granule was rounded triangular and some elliptical. The size distribution of starch granule was also analyzed. The mean value of minor axis, major axis and the ratio of those were 4.785 $\mu\textrm{m}$, 7.30 $\mu\textrm{m}$ and 0.68, respectively. The surface micro-structure of acorn starch gels were investigated by SEM. Acorn crude and refined starch gel were very different in surface micro-structure. X-ray diffraction pattern of acorn starch was C-type, and the pattern of acorn starch gels were extremely different because of disintegration of starch granules by gelatinization. The diffraction intensity of acorn refined starch gel was slightly higher than crude starch gel.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.326-332
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• 1983

Acorn wine was manufactured experimentally with koji inoculated the strain producing acorn tannin hydrolyzing enzyme in order to apply fungal tannase to food processing. Starch value of several Korean acorns was found to be 72.84 and the acorns were worthy of use as a carbohydrate food. Mixed koji was prepared by combination of rice and acorn powder at a ratio of 50to 50 and inoculation of Aspergillus oryzae producing amylase and Aspergillus sp. AN-11 producing tannase into the mixture in order to hydrolyze efficiently acorn tannin inhibiting alcohol fermentation in the medium, and then the mixed koji was used as a suitable koji to manufacture acorn wine. Acorn wine brewed with medium of the acorn powder treated with water and cooked and the mixed koji prepared was superior about two times to that brewed with medium of untreated acorn powder and general koji with respect to the rate of alcohol production and sugar fermentation during the 1st and 2nd brewing.

• 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 the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.770-776
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• 2000

Pasting gelatinization of acorn flours which were prepared with soaked nut and sediment at 7.8$^{\circ}C$ for 0, 1, 2, 3 and 4 days were investigated. The peak temperature of gelatinization of untreated acorn flour (0-0) by Rapid Visco Analyzer was 73.1$^{\circ}C$, respectively, but those of flours were decreased by soaking. Peak viscosity, setback and breakdown of acorn flours were increased by soaking. In addition, consistency was increased by soaking treatment. From the result of the pasting properties, gel formation ability of acorn flour was increased with increasing soaking days of acorn nut and soaking times of sediment. The gelatinization temperature examined by X-ray diffractometry was lowered with increasing of soaking days. The observation of microstructure through a scanning electron microscope revealed that gelatinized acorn flour showed loser their original shape and structure than that of with out soaking treatment (0-0). The degree of gelatinization under the fixed temperature increased with increasing soaking days. From these results, it might be concluded that the increase of soaking days and soaking times is the factor affecting the gelatinization of acorn flour.

• 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.

• Food Science and Biotechnology
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• v.14 no.2
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• pp.233-237
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• 2005

Rheological properties of acorn flour-guar gum mixtures (4% w/w) at different guar gum concentrations (0, 0.2, 0.4, 0.6, and 0.8% w/w) were evaluated in steady and dynamic shear. The acorn flour-guar gum mixtures at $25^{\circ}C$ showed high shear-thinning flow behavior (n= 0.20-0.27). Consistency index (K), apparent viscosity (${\eta}_{a,100}$), and Casson yield stress (${\sigma}_{oc}$) increased with the increase in guar gum concentration. Within the temperature range of $25-70^{\circ}C$, the {\eta}_{a,100}$ of mixtures obeyed the Arrhenius relationship with high determination coefficient ($R^2=\;0.974-0.994$). Activation energy values (5.37-6.77 kJ/mole) of acorn flour dispersions in the mixtures with guar gum (0.2-0.8%) were much lower than that (12.5 kJ/mole) of acorn flour dispersion (0% guar gum). Storage modulus (G'), loss modulus (G"), and complex viscosity (${\eta}^*$) increased with the increase in guar gum concentration. Dynamic rheological data of 1n (G', G") versus ln frequency (w) of guar gum-acorn flour mixtures had positive slopes with G' greater than G" over most of the frequency range, indicating that they exhibited weak gel-like behavior.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.749-760
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• 2013

The purpose of this study was to examine the characteristics of quality and anti-oxidation of brown rice Jeung-pyun dough containing different amounts of acorn flour. The acorn flour added brown rice Jeung-pyun's specific volume increased at the second week of storage to 1.33~1.55mL/g, while the fourth week decreased to 1.57~1.64 mL/g. The pH of Jeung-pyun (5.19~5.36), in general, was higher than dough (5.14~5.22). The gelatinization was decreased to 1.69~2.24 range as storage period increased. Especially, the 9% acorn flour added group's gelatinization was delayed than other groups. The mechanical texture of hardness as the amount of acorn flour increased, while adhesiveness, cohesiveness and springiness reduced. The sensory evaluation results show that 9% acorn flour added group had generally high marks in appropriateness.

• Food Science and Preservation
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• v.23 no.3
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• pp.445-452
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• 2016

In this study, physicochemical properties of acorn flour was investigated, and characteristics of the Jeung-pyun dough added with the acorn flour at various concentrations were evaluated after storage at -$18^{\circ}C$ for 4 weeks and fermentation. Total polyphenolic content, electron donating ability (EDA) of 0.5%, gelatinization onset temperature (To), gelatinization peak temperature (Tp), and gelatinization conclusion temperature (Tc) of acorn flour were 3,525.12 mg%, 16.71%, $68.41^{\circ}C$, $73.83^{\circ}C$, and $82.96^{\circ}C$, respectively. These all values were increased in the Jeung-pyun dough possibly due to addition of the acorn flour. The yeast count was not affected by the addition levels of acorn flour and the frozen storage period before fermentation. The amount of carbon dioxide gas evolved from Jeung-pyun dough during fermentation was significantly changed with the concentration of acorn flour, but it was negligible. The Jeung-pyun added with 6% acorn flour showed an small increase in the amount of carbon dioxide after frozen storage of 1 wk and fermentation. The pH of the fermented Jeung-pyun samples decreased along with the increasing storage period as well as the increasing acorn flour content, ranging from 4.21 to 5.34. Therefore, the frozen Jeung-pyun dough containing 6~15% of acorn flour and stored for 3 weeks was the most desirable among all the tested samples in this study.