• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.235-240
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• 1991

Starch phosphates were prepared from the corn starch mixed with 2% sodium tripolyphosphate by twin-screw extruder with a feed rate of 20 kg/hr and an extrusion temperature of $130^{\circ}C$, and the effects of extrusion variables on the physicochemical properties (target parameters) of starch phosphates were investigated. Interrelations of system parameters (specific mechanical energy and extrudate moisture) and rheological properities of starch was analyzed by using the response surface analysis. Degree of substitution (DS) was increased with increasing the feed moisture, and showed the maximum value at the screw of near 250 rpm, Degree of gelatinization was proportionally increased with increasing the screw speed and decreasing the feed moisture. Apparent viscosity of the paste was increased with increasing the feed moisture, but it was not significantly affected by the screw speed. It was found by scanning electron microscopy that the starch microgranules were much more degradaded, and as consequent result, the intrinsic viscosity was decreased, whereas, water solubility index was increased. The rate of retrogradation of the gels was retarded with increasing DS and decreasing viscosity.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.772-779
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• 1989

The effects of screw speeds and moisture contents on the physical properties of texturized extrudate from isolated soy protein were examined by using a single-screw extruder. The screw speeds and moisture contents tested were in the range of 122-334 rpm and 20-35%, respectively, and die temperature were $90-145^{\circ}C$. The texturization characteristics such as nitrogen solubility index, integrity index, chewiness, density, rehydration ratio, and lightness after rehydration were appeared to be influenced by screw speed and moisture content. As the screw speed increased and moisture content decreased, die temperature, nitrogen solubility index, integrity index, lightness before and after rehydration were increased, while chewiness, density, water content of final extrudate wee decreased. The rehydration rate was changed drastically at the feed moisture content of 30% in particular. As the moisture content decreased, the air cell size became large and its number was increased. The effects of interaction between screw speed and moisture content of raw materials on the extrudate characteristics were tested by the analysis of variance.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.65-71
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• 1997

The energy supplied by motor of extruder, being known mostly to be dissipated as heat, was classified into two kinds of energy: a thermal energy by heat dissipation and a purely mechanical energy. The thermal energy was defined as a energy in terms of temperature rise and the mechanical energy as the motor energy minus the heat dissipated energy. A method to derive the thermal energy and the relative mechanical energy (the mechanical energy calculated regarding the mechanical energy at the lowest screw speed as zero) under the condition of constant barrel temperature was developed by which an extrusion case was analyzed. When extruding com grits with moisture $(27{\sim}37%)$ at low barrel temperature $({\leq}80^{\circ}C)$, the thermal energy slightly increased with increase in the moisture content, whereas the relative mechanical energy increased to a great extent. When increasing the screw speed, the thermal energy was nearly kept constant, whereas the relative mechanical energy largely varied. It is concluded that as the moisture content increases, the role of the mechanical energy becomes more effective than the heat energy dissipated from the motor energy.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.214.2-215
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• 2003

압출조리 공법에 의한 한국형 쌀 이유식 제조에서 아밀라제 첨가가 압출미분의 물성 변화에 미치는 영향을 알아보았다. 압출조리기의 스크류 회전수는 200rpm, 원료의 사입속도는 180g/min로 고정하여 작동하였다. 원료 쌀가루의 수분함량은 18, 23, 28%로 가수하였고 첨가된 아밀라제는 Bacillus licheniformis로부터 분리한 Termamyl 120LS(NOVO사), Bacillus amylolichuefaciens로부터 분리한 BAN 240L(NOVO사) 및 맥아분말이다. 아밀라제 첨가에 의해 압출미분의 수용성지수는 3배까지 증가했고, 환원당 생성량은 원료의 수분함량에 크게 영향을 받아 28% 수분함량에서 급격히 증가하여 수용성지수와는 다른 경향을 나타내었다. 겔 투과크로마토그래피에 의한 분자량적 구조 변화 측정 결과 아밀라제 첨가에 의해 고분자 획분이 상당히 감소했으며 상대적으로 저분자 획분이 증감함을 알 수 있었다. 아밀라제의 잔존환성은 아밀라제 종류에 따라 다르며 가장 내열성인 Termamyl 120LS의 경우 용융부위 온도 14$0^{\circ}C$에서 27%까지 감소하였다. 침전법에 의한 분산특성은 아밀라제 작용에 의해 수용성 물질이 증가함에 따라 침전층의 감소를 나타내었으나 처리온도가 14$0^{\circ}C$로 증가하면 침전층의 높이는 증가하였다. 겉보기 점도는 아밀라제 첨가에 의해 무처리 압출미분의 1/4~1/200로 감소하였다. 시판 이유식의 권장농도에서의 점도와 같은 점도 수준에 도달하기 위해서는 원료의 수분함량(18, 23, 28%), 아밀라제 종류 및 첨가량, 계량부위 온도에 따른 각 작동조건의 압출미분을 최고 1.8배의 양을 사용할 수 있었다. 이상에서 살펴본 바와 같이 원료 쌀가루에 첨가된 아밀라제가 압출조리기내를 통과하면서 쌀가루의 가수분해를 일으켜 환원당 등 수용성 물질이 증가하고 분산특성이 좋아지며 점도가 낮아지고 결국 이유식의 열량밀도를 증가시킬 수 있음을 확인할 수 있었다.

• The Korean Journal of Rheology
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• v.4 no.2
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• pp.99-106
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• 1992

전방향족 폴리에스테르계 열방성 액정중합체(Vectra A-950)를 대상으로 유로가 확 장되는 다이로의 압출을 통하여 액정 섬유상의 배향 특성을 조사하고 이들이 기계적 특성에 미치는 영향을 살펴보았다, 다이의 확장 효과에 의하여 중심에서는 유동방향과 수직방향으 로 섬유상이 이중 배향되었으며 가장자리에서는 주로 유동방향으로만 배향이 일어났다. 그 리고 배향 특성은 두께방향으로 상하 대칭성을 갖는 바깥 영역과 중간영역으로 구별되었으 며 겉층은 유동방향으로 배향되고 속층은 중심에서 멀어지면서 배향각이 점진적으로 달라졌 다. 이런한 시편의 기계적 강도는 압출다이의 확장각이 증가하거나 스크류 속도가 증가함으 로 따라 유동방향이나 그 수직방향 모두 현저한 증가를 보였으나 파단신도는 유동방향은 감 소하고 수직방향은 증가하여 증가하여 결과적으로 거의 비슷하였으며 파단신도가 배향상태 를 가장 잘 반영하는 기계적 특성임을 알 수 있었다.

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.29-32
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• 2006

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.10
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• pp.1742-1747
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• 2004

Effects of raw material composition, feed moisture and process temperature on chemical, physical and sensory properties of extrudates produced by a single-screw extruder from the mixtures of rice flour, isolated soy protein and file fish were evaluated through response surface methodology (RSM). Nitrogen solubility index (NSI), integrity index (II), rehydration ratio (RR), density, and the external appearance were measured as indices of physicochemical and sensory properties of extrudates. RR was negatively correlated with density (R=-0.742, p<0.0l). Increased amounts of rice flour in feed mixtures resulted in increased RR. The extrudate prepared from the mixtures of ISP, rice flour and file fish showed the highest sensory score at which extrusion temperature was 13$0^{\circ}C$ or above.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.303-309
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• 1988

The heat generation at the start-up period of an autogeneous single screw extruder was determined with various feed materials, die structure and operational conditions. The highest heat generation rate was observed with defatted soybean meal, while the lowest value was obtained with rice flour, and wheat and barley flour showed the intermediate rate. As the moisture content of the flour decreased and the screw speed increased, the electric power requirement and heat generation rate increased. The temperature at compression section increased with the decrease in the particle size. The same effect was also observed as breaker plate was installed. The optimum operation was established as the temperature profile was maintained in decreasing order of metering section, die and compression section.

• Korean Journal of Food Science and Technology
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• v.22 no.4
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• pp.451-455
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• 1990

The extrusion characteristics of pork rind mixed with corn flour were investigated. The blends of pork rind to corn flour in the ratio of 1 : 2, 1 : 1, 2 : 1 and 3 : 1(w/w) were made and each blend was dried up to 5, 10 and 15% moisture content. The blends were extruded by single screw extruder. The extrusion characteristics of each extrudate were as follow. The highest value of expansion ration was attained by mixing pork rind and corn flour in the ratio of 1 : 1, containing 5% moisture content. As the rind content to the corn flour mixture was increased, the bulk density, water absorption index, breaking stregth and redness, of the extradate increased, but the lightness and yellowness decreased. It was concluded that a high quality snack food could by produced by extrusion-cooking the mixture of pork rind and corn flour.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.80-85
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• 2016

Carbon fiber-reinforced composite materials have been widely used in various industrial fields, but there are limits to increasing their strength and stiffness, because of the short-length fibers that are impregnated in them. In this study, a lab-scale small extruder system was developed with the capability to perform the carbon fiber impregnation and extrusion process in order to evaluate the properties of long-length carbon fiber reinforced thermoplastic composite materials molded by the LFT-D method. Specimens were made with the small extruder to press-mold long-length carbon fiber composite materials and evaluate their material properties. As a result, it was found that the carbon fiber length, press load and carbon fiber contents have a considerable influence on the strength and stiffness. Additional studies on such factors as the mixing screw design and coating of the carbon fiber are needed in order to improve the mechanical properties of carbon fiber composite materials.