• Environmental Engineering Research
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• 제24권3호
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• pp.376-381
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• 2019

In this study, a poly(vinyl) alcohol/sodium alginate (PVA/SA) mixture was used to fabricate core-shell structured gel beads for autotrophic single-stage nitrogen removal (ASNR) using aerobic and anaerobic ammonia-oxidizing bacteria (AAOB and AnAOB, respectively). For stable ASNR process, the mechanical strength and oxygen penetration depth of the shell layer entrapping the AAOB are critical properties. The shell layer was constructed by an interfacial gelling reaction yielding thickness in the range of 2.01-3.63 mm, and a high PVA concentration of 12.5% resulted in the best mechanical strength of the shell layer. It was found that oxygen penetrated the shell layer at different depths depending on the PVA concentration, oxygen concentration in the bulk phase, and free ammonia concentration. The oxygen penetration depth was around $1,000{\mu}m$ when 8.0 mg/L dissolved oxygen was supplied from the bulk phase. This study reveals that the shell layer effectively protects the AnAOB from oxygen inhibition under the aerobic conditions because of the respiratory activity of the AAOB.

• 대한건축학회논문집:구조계
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• 제33권12호
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• pp.63-70
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• 2017

When industrial by-products like slag and fly ash are using in concrete with cement, it improves strength and durability against external deterioration factors by densifying the structure through potential hydraulic and pozzolanic reaction. But it has been pointed out that high dependence on the quality variation and the curing condition using a admixure material for concrete. In this study, the characteristics of internal micropore structure according to curing condition were analyzed for pastes and mortar specimens under using blast furnace slag powder. As a result, the variation of compressive strength and the internal microstructure were observed according to curing conditions by binder type. Particularly, using blast furnace slag powder, decrease in compressive strength were clearly observed in indoor and carbonation curing compared with water curing. The pore structure analysis also clearly observed the decrease of the gel pore existing in the CSH hydrate layer and the increase of the capillary pore in indoor and carbonation curing compared with water curing condition.

• Asian-Australasian Journal of Animal Sciences
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• 제20권8호
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• pp.1285-1291
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• 2007

This research investigated variation in the improvement of the texture of chicken and pork sausages induced by microbial transglutaminase (MTG). The extractability of myofibrillar proteins from these sausages as well as the ${\varepsilon}-({\gamma}-glutamyl)$lysine (G-L)　content were also investigated. MTG treatment of sausages significantly increased the breaking strength values in both meat types, especially for samples incubated at $40^{\circ}C$. However, values of the breaking strength in both meat types were increased differently. The variation in protein extractability of samples incubated at $40^{\circ}C$ for both meat types could lead to some consideration of the mechanisms and the high accessions of myosin heavy chain (MHC) to MTG. SDS-PAGE analysis showed significant changes in the density of the bands after adding MTG, especially for the pork samples in which the bands disappeared totally. The G-L content in the presence of MTG was double that in control samples of both meat types. This study suggests that the binding ability of myofibrillar proteins with MTG is strong. This leads us to suggest that MTG functions positively with different improvements in the texture of chicken and pork products that are treated mechanically, such as sausages. Variability in gel improvement level between chicken and pork sausages was observed; this resulted from the variation in meat proteins in response to MTG, as well as to the original glutamyl and lysine content.

• 한국수산과학회지
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• 제33권1호
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• pp.70-74
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• 2000

우뭇가사리로부터 조한천을 조제하고, 이를 실제 산업에 적용할 목적으로 $0.4\;{\mu}m$ 기공을 가지는 여과 막을 microfiltration한 후, $50{\circ}C$의 온수로써 가용성 물질을 제거하고, 0.25 N NaOH로 $70{\circ}C$에서 2시간 처리하는 알칼리 처리를 거쳐 미생물 배지용 한천을 조제하였다. 이화학적 특성을 측정한 결과에 의하면, 겔강도는 $460g/cm^2$에서$738g/cm^2$으로 상승하였고, 점도는 12 cp에서 5.2 cp로, 황산기 함량은 $1.8{\%}$에서 $0.4{\%}$로, 그리고 이수율은 $10.3{\%}$에서 $5.4{\%}$로 저하하여 제품의 품질이 월등히 향상되었다. 상용되는 미생물 배지용 한천은 겔강도가 $358{\~}368g/cm^2$, 점도는 8 cp, 황산기 함량은 $2.18{\~}2.39{\%}$ 및 시너레시스율은 $11.3{\~}12.4{\%}$로 분석되어 본 실험법으로 정제한 한천이 물성 및 성분에 있어서 휠씬 우수 하였다.

• 한국축산식품학회지
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• 제34권1호
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• pp.122-126
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• 2014

This study was performed to evaluate the effects of chicken breast meat on the quality of mackerel sausages. The mackerel sausages were manufactured by additions of 5%, 7%, and 10% of chicken breast meat. The lightness of mackerel sausages showed no significant differences between the control and addition groups. The redness increased in a dose-dependent manner, but the yellowness decreased significantly with the addition of 7% chicken breast meat (p<0.05). The whiteness value of mackerel sausage added with 7% chicken breast meat was significantly higher than those of the other groups (p<0.05). In texture analysis, the hardness and adhesiveness of the mackerel sausage added with 5% of chicken breast meat showed no significant differences as compared to the control. However, the mackerel sausages added with 7% and 10% of chicken breast meat showed a dose-dependent decrease. The gel strength of the mackerel sausage added with 5% chicken breast meat was not significantly different from the control, but the addition of 7% and 10% chicken breast meat reduced the gel strength of the mackerel sausage. In sensory evaluation, the mackerel sausages prepared with chicken breast meat have higher scores in smell, taste, texture, hardness, chewiness, and overall preference as compared to the no addition group. Therefore, these results suggest that the optimal condition for improving the properties within mackerel sausages was 5% addition of chicken breast meat.

• 환경생물
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• 제24권2호
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• pp.179-185
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• 2006

자연산 및 양식산 민어, Miichthys miiuy의 체성분 및 탄력의 계절적 변화를 조사하였다. 민어육에 대하여 수분, 조단백질, 지방, 회분 및 아미노산 조성을 자연산과 양식으로 구분하고 아울러 비교 분석하였다. 양식산 민어는 천연산에 비해 수분함량이 다소 많은 반면 조단백질, 조지방 함량은 약간 적었으나 대체로 성분조성이 비슷하였다. 아미노산 함유량의 경우 전체적으로 자연산이 양식산 민어육보다 함량이 높은 경향을 나타내었다. 이러한 결과는 필수아미노산과 아미노산의 비에서도 위와 유사한 경향을 보였으며, 필수아미노산과 전체 아미노산의 비는 자연산과 양식산 모두 같거나 비교적 큰 차이를 나타내지 않았다. 불포화지방산인 EPA (Eicosapentaenoic Acid)와 DHA (Docosahexaenoic Acid) 조성은 자연산보다 양식산에서 높게 나타났다. 민어육의 탄력을 나타낸 gel strength, max weight 및 hardness는 자연산이 양식산에 비해 높은 경향을 나타냈었다.

• Fisheries and Aquatic Sciences
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• 제17권2호
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• pp.167-173
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• 2014

Surimi (or fish paste) products are one of the most representative processed seafoods in Korea. In a previous study, we evaluated the potential use of rice flour as an agent to replace wheat flour in surimi products. In this study, we optimized the content of rice flour and water in surimi products using response surface methodology. Rice flour content ($X_1$, w/w) and water content ($X_2$, v/w) were chosen as independent variables and gel strength ($Y_1$) and overall acceptance ($Y_2$) as dependent variables. Optimal conditions of $X_1$ and $X_2$ were 14% and 9.1%, respectively, and the predicted values of the multiple response optimal conditions were $Y_1=656.4(g{\cdot}cm)$ and $Y_2=6.34$. Under optimal conditions, the experimental values of $Y_1$ and $Y_2$ were $647.8(g{\cdot}cm)$ and 6.21, respectively, which were similar to the predicted values. Surimi products that are prepared under optimum conditions were similar in gel strength to those of commercial products. However, its sensory evaluation score was higher than that of the commercial products. In conclusion, rice flour can not only be used as an alternative to wheat flour, but it also can be used to improve the quality of surimi products.

• 한국수산과학회지
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• 제28권3호
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• pp.331-337
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• 1995

해조류 중 생산량이 많고 건강식품 소재로서의 가능성이 높은 미역과 다시마 해조묵을 제조하여 수침저장 중 저장 온도와 시간에 따른 생균수, pH, 적정산도, 겔강도 및 TVN의 변화를 측정하여 적정저장 조건을 검토한 결과 묵 저장 중 겔강도는 약화되었으며, TVN, 생균수는 증가하였다. 조체묵의 수침저장은 $32^{\circ}C$에서는 3일, $18^{\circ}C$ 이하에서는 15일 저장까지도 가능하였으며, 두유혼합묵은 조체묵 보다는 저장 기간이 짧아서 $18^{\circ}C$ 저장시 3일까지 가능한 것으로 판단되었다.

• 한국재료학회지
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• 제24권1호
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• pp.48-52
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• 2014

The Mg-enriched magnesium aluminum silicate (MAS) glass is known for its higher mechanical strength and chemical resistance. Among such glasses, cordierite ($Mg_2Al_4Si_5O_{18}$) is well known to have a low thermal expansion and low melting point. Polycrystalline engineering ceramics such as alumina can be strengthened by a surface modification with low thermal expansion materials. The present study involves the synthesis of cordierite by a sol-gel process and investigates the effect of glass penetration on the surface of alumina. The cordierite powders were prepared from $Al(OC_3H_7)_3$, $Mg(OC_2H_5)_2$ and tetraethyl orthosilicate by hydrolysis and condensation reaction. The cordierite powders were characterized by X-ray diffraction (XRD, Rigaku), scanning electron microscope (SEM, JEOL: JSM-5610), energy dispersive spectroscopy (EDS, JEOL: JSM-5610), and universal testing machine (UTM, INSTRON). The X-ray diffraction patterns showed that the synthesized particles were ${\mu}$-cordierite calcined at $1100^{\circ}C$ for 1 h. The shape of synthesized cordierite was changed from ${\mu}$-cordierite to ${\alpha}$-cordierite with increasing calcination temperature. Synthesized cordierite was used for surface modification of alumina. Cordierite powders penetrated deeply into the alumina sample along grain boundaries with increasing temperature. The results of surface modification tests showed that the strength of the prepared alumina sample increased after surface modification. The strength of a surface modified with synthesized cordierite increased the most, to about 134.6MPa.

• 한국염색가공학회지
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• 제25권3호
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• pp.172-180
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• 2013

Aramid fibers are being used increasingly in a wide range of application due to low density, high specific strength, high modulus, and high thermal resistance. But owing to its special physical and chemical structures, it is sensitive to absorb the ultraviolet light which will degrade the fiber's useful mechanical properties and structure. In this paper, the sol-gel technique was used to improve the photo-stability of p-aramid fibers. $TiO_2$, modified $SiO_2$/$TiO_2$ sol were used as coating solutions. The influence of the such coatings on the photo-stability of p-aramid fiber was investigated by an accelerated photo-ageing method using xenon lamp. The photo-stability of p-aramid fiber showed obvious improvement after the modified silica binding coating. But the amorphous $TiO_2$ sol coatings showed a negative effect. After 144h light exposure, the modified silane binder-coated fibers showed less degradation in mechanical properties with the retained tensile strength greater than about 70% of the original value.