A study on the decolorization method of salt-fermented anchovy sauce using activated carbon was carried out. The anchovy sauce filtered with a diatomaceous membrane after heating at 85℃ for 20 min was reacted with 3.0% (w/w) activated carbon with pH 4.5 at 55℃ for 2 hr. The color difference value and turbidity related to the decolorizing effect showed excellent improvement results with a difference of 23% and 88%, respectively. The overall taste and color preference of decolorized anchovy sauce were significantly increased in shrimp sauce by 0.4-0.5 points (p<0.05). In order to minimize the precipitation of amino acid during storage, 1% silicon dioxide or gelatin was mixed and filtered after the activated carbon reaction. Turbidity, as index of sedimentation, was improved by 15% at 30℃ for 2 weeks. The recycle system with activated carbon coated membrane filter reduced the processing time and cost on decolorization of anchovy sauce. When the concentrated anchovy sauce was recirculated, the amount of total protein as an indicator of taste compounds was increased by 125%, which is 1.8% compared to the conventional 0.8%, indicating that it is highly useful as a liquid seasoning.
Abstract Y2Ti2O7 nanoparticles (0.3 mol%) have been successfully synthesized by the co-precipitation process. The samples, adjusted to pH7 with ammonia solution as catalyst and calcined at 700~900 ℃, exhibit very fine particles with close to spherical shape and average size of 10-30 nm. It was possible to control the size of the synthesized Y2Ti2O7 particles by manipulating the conditions. The Y2Ti2O7 nanoparticles were coated on a glass substrate by a dipping coating process with inorganic binder. The Y2Ti2O7 solution coated on the glass substrate had excellent adhesion of 5B; pencil hardness test results indicated an excellent hardness of 6H. The thickness of the thick film was about 30 μm. Decomposition of MB on the Y2Ti2O7 thin film shows that the photocatalytic properties were excellent.
The effect of Al content on the processing of reaction-bonded Al2O3 (RBAO) ceramics using 40v/o ~ 80v/o Al- Zn-Mg alloy powder was studied in order to improve traditional RBAO ceramic processes that use ~ 40v/o pure Al powder. The influence of high Al content in starting Al2O3-Al alloy powder mixtures on its particulate characteristics, reaction-bonding, microstructure, physical and mechanical properties was revealed. Starting Al2O3-Al alloy powder mixtures with 40v/o ~ 80v/o Al alloy powder were milled, reaction-bonded, post-sintered, and characterized. With an increasing Al alloy content, the milling efficiency of Al alloy powder was lowered, resulting in a larger particle size after milling. However, in spite of the larger particle size of Al alloy powder, the oxidation, i.e., reaction-bonding, of the Al alloy was successfully completed via solid and liquid state oxidation, in which the activation energy of the oxidation was nearly the same regardless of Al alloy content. After reaction-bonding and post-sintering at 1600 oC, RBAO ceramics from 80v/o Al alloy content showed a relative density of ~97% and a flexural strength of 251 MPa compared to ~ 96% and 353 MPa for RBAO ceramics from 40v/o Al alloy content, respectively. The lower flexural strength at 80v/o Al alloy content was due to the weak spinel phase that formed from Zn, Mg alloying elements in Al.
In this paper, two kinds of advanced powder processing techniques Metal Injection Molding (MIM) and Direct Laser Forming (DLF) are introduced to fabricate complex shaped Ti alloy parts which are widely used for med- ical and aerospace applications. The MIM process is used to strengthen Ti-6Al-4V alloy compacts by addition of fine Mo, Fe or Cr powders. Enhanced tensile strength of 1030 MPa with 15.1% elongation was obtained by an addition of 4 mass%Cr because of the microstructural modification and also the solution strengthening in beta phase. However, their fatigue strength was lower compared to wrought materials, but was improved by HIP. Subsequently, the effect of feed- ing layer height (FLH) on the characteristics of the DLF compacts was investigated. In the case of 100 µm FLH, sur- face roughness was improved and nearly full density (99.8%) was obtained. Also, tensile strength of 1080 MPa was obtained, which is higher than the ASTM value.
Nano-sized cobalt powder was fabricated by wet chemical reduction method at room temperature. The effects of various experimental variables on the overall properties of fabricated nano-sized cobalt powders have been investigated in detail, and amount of NaOH and reducing agent and dropping speed of reducing agent have been prop- erly selected as experimental variables in the present research. Minitab program which could find optimized conditions was adopted as a statistic analysis. 3D Scatter-Plot and DOE (Design of Experiments) conditions for synthesis of nano- sized cobalt powder were well developed using Box-Behnken DOE method. Based on the results of the DOE process, reproducibility test were performed for nano-sized cobalt powder. Spherical nano-sized cobalt powders with an average size of 70-100 nm were successfully developed and crystalline peaks for the HCP and FCC structure were observed without second phase such as Co(OH).
This study was conducted to monitor and evaluate microbial contamination during manufacturing process in 6 red pepper powder factories. Red pepper powder samples were taken from manufacturing facilitates, working area and workers’ hands to determine sanitary indicator bacteria (SIB) such as aerobic bacteria and coliform group as well as pathogenic indicator bacteria (PIB) such as Staphylococcus aureus, E.coli, Salmonella spp., Listeria monocytogenes, and Bacillus cereus. The results indicated that SIB in primary materials was detected as low as 3 log units and E.coil and Staphylococcus aureus of PIB were detected. After grinding process, aerobic bacteria, fungi, and coliform group increased 52% and 108%, respectively. In final products, PIB was not detected except for one found Staphylococcus aureus by which workers’ hands were contaminated. Moreover, UV detectors in all the manufacturers were not able to reduce bacteria. Thus, this data suggest that a stringent safety management be needed to prevent cross contamination, and also reconsider effectiveness of facility.
The purpose of this study was to bake sweet rice muffins with oak mushroom (Lentinus edodes) powder. The process included substituting sweet rice flour for cake flour and adding oak mushroom powder. This study determined the optimal mixing conditions of oak mushroom muffins by adjusting the amounts of oak mushroom powder, whole eggs, and soybean oil. The mixing conditions for the oak mushroom muffins included 3 categories: oak mushroom powder (X1), whole eggs (X2), and soybean oil (X3) by Central Composite Design (CCD) which was optimized by Response Surface Methodology (RSM). Oak mushroom muffin formulation was optimized using rheology. Yellowness (p〈0.001) and redness (p〈0.05) displayed a linear model pattern, whereas lightness (p〈0.05) was represented by a quadratic model. Among the sensory properties, variables that appeared to show significant values such as appearance (p〈0.5), texture (p〈0.5), and overall quality (p〈0.5) were used to identify optimums. The result of mechanical properties showed significant values in gumminess (p〈0.5) and chewiness (p〈0.5). The numerical and graphical methods used in this study determined that the optimum formulation for oak mushroom powder sweet rice muffins was 8.75 g of oak mushroom powder, 235.95 g of whole eggs, and 19.93 g of soybean oil.
1. 원료 형태별 청국장의 발효시간에 따른 건물중은 콩, 환, 분말의 모든 원료형태에서 발효시간이 경과할수록 건물의 중량이 감소하는 경향을 보였다. 2. 원료 형태별 청국장의 발효시간에 따른 진의 길이 변화를 측정한 결과, 모든 원료 형태에서 발효시간이 경과할수록 진의 길이가 증가하는 경향을 보였으며, 48시간 이후에는 그 증가치가 완만함을 보였다. 태광콩을 콩의 형태로 발효하였을 때 진의 생성이 가장 많았고, 분말을 1cm의 두께로 발효하였을때 진이 거의 생성되지 않았다. 3. 원료 형태별 청국장의 발효시간에 따른 생균수의 변화를 측정한 결과, 콩 형태로 발효시켰을 경우 모든 품종에서 비슷한 수준의 생균수가 측정되었다. 환 형태로 발효시켰을 경우 12시간 이후에 생균수가 급격히 증가하다가 24시간 이후 증가치가 완만해졌다. 분말형태로 발효시켰을 경우 시간에 따라 경시적으로 증가하였다. 4. 원료 형태별 청국장의 발효시간에 따른 색도의 변화를 측정한 결과, 모든 원료 형태에서 발효시간이 경과할수록 명도는 흑색에 가까워졌고, 색상과 채도의 경우는 각각 적색과 황색을 띠는 쪽으로 변화하였다. 5. 원료 형태별 청국장의 발효시간에 따른 pH의 변화를 측정한 결과, 모든 원료 형태에서 발효시간이 경과할수록 알칼리성으로 변화하였다. 6. 원료 형태별 청국장의 발효시간에 따른 isoflavone 함량의 변화를 측정한 결과, 발효 후 48시간까지 isoflavone의 함량이 증가하다 감소하는 경향을 보였다. 7. 청국장을 건조온도를 달리하여 균의 재생능력을 실험해본 결과 동결건조를 하였을 때 가장 많은 수의 균이 존재하였다. 8. 분말 또는 분말 (환)의 형태로 청국장을 만들 경우 종자 이용 시 보다 청국장의 품질이 떨어졌으며 분말 (환)을 이용하여 경제적인 청국장 제조를 위해서는 더 많은 연구가 필요한 것으로 고려되어 진다.
대두에서 산패취를 발생시키는 lipoxygenase 효소를 비가열 전처리 방법인 초고압 처리 방법을 이용하여 효소의 활성도의 변화를 확인하였다. 연구 결과 초고압 처리에 의해 lipoxygenase 효소의 활성도가 감소하는 것을 확인하였다. 또한 lipoxygenase 효소의 활성도 감소에 의해 대두의 저장성에 미치는 영향을 확인하기 위해 국산 대두와 연해주 대두를 이용하여 저장 실험을 실시하였다. 실험 결과 국산 대두의 경우 초고압 처리에 의해 lipoxygenase 효소의 활성도가 감소하였으나 TBA값에 영향을 주는 자동산화 등의 화학반응에 의해 TBA값이 지속적으로 증가함을 보여주었다. 그러나 연해주 대두의 경우에는 초고압 처리를 한 시료의 TBA값의 증가정도가 상대적으로 낮게 측정된 것을 확인하였다. 이는 연해주 대두가 항산화 성분을 국산콩에 비하여 많이 포함하고 있어 초고압 처리에 의한 lipoxygenase 효소의 불활성과 함께 항산화 성분의 영향으로 TBA값의 저장 중 증가 정도가 낮게 측정된 것으로 판단되어진다.
Quality characteristics of dasik were studied with varied the levels of rice grain particle size and green tea powder and compared them with commercially sold dasik. Among the samples with the same number of grinding times, the sample groups with the higher amount of green tea showed significantly the less mosture content(p<0.05). Hardness was higher in the samples containing higher amount of green tea among the ones with the same grain size (p<0.05). The M13G0.5 was evaluated to have the highest savory aroma with significance (p<0.05), and C1 to have the highest sweetness by sensory analysis. The developed dasik samples with lower rice grain particle size had significantly lower adhesiveness, chewiness, gumminess, and cohesiveness compared to those of commercial sample groups. In sensory tests, the compared groups showed significantly the higher savory aroma and flavor and very lower hardness when compared to those of commercial sample groups. With the results above, dasik with with varied the levels of rice grain particle size and green tea powder were developed with improved qualities compared to those of commercially sold dasik.
The microstructure and electrical conductivity of CNTs dispersed nanocomposites depending on the powder processing and CNTs content were demonstrated. The composite powders with homogeneous dispersion of CNTs could be synthesized by a catalytic route for direct formation of CNTs on nano-sized Fe dispersed powders. The sintered nanocomposite using the composite powder with directly synthesized CNTs showed homogeneous microstructure and enhanced elelctrical conductivity. The influence of powder processing on the properties of sintered nanocomposites was discussed by the observed microstructural features.
The 21st Century Frontier Program, which is one of the R&D programs funded by Korean government, was launched in 1999 to elevate the status of Korean science and engineering capabilities to the advanced nation in the strategic fields. Currently, 23 different fields of science and engineering programs are carried out by researchers in institutes, universities and industries. Center for Advanced Materials Processing (CAMP) was formulated in 2001 to develop the advanced materials as well as to improve the parts manufacturing process. The main role of CAMP is proposing and forecasting the long term vision in Materials Processing Technology and also supporting the project teams for their best performance in R&D. The CAMP program consists of 5 research areas such as, Multi-layer Ceramic Electronic Parts, Powder Formed Precision Parts, 3 Dimensional Polymer Based Composites, Functional Metal Sheets, Parts Integration Technology. An introduction of R & D activities at CAMP, specially focusing on powder metallurgy, will be presented.
Processing of W-Cu graded materials from attritor-milled W-CuO mixtures is described. The powder reduction steps are investigated by TG and XRD analyses and by microstructural observations (SEM, TEM). Sintering of reduced powder with different compositions is analysed by dilatometry. Sintering behaviour of the graded component processed by co-compaction of a 10/20/30wt%Cu multi-layer material is briefly discussed. Liquid Cu migration is observed and smooths the composition gradient. Perspectives to control this migration are discussed.
In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below in air was times higher than that of the air- passivated particles.