• 산업식품공학
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• 제15권2호
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• pp.148-154
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• 2011

사출구 구조가 압출성형의 목적변수인 팽화특성에 영향을 미치는지 알아보기 위하여 사출구의 기하학적 구조를 사출구상수로 산출하여 사출구상수와 수분함량에 따른 팽화특성을 비롯한 비기계적 에너지 투입량, 수분용해지수, 수분흡착지수를 분석하였다. 압출성형 공정변수는 수분함량(20, 25%), 사출구멍의 길이와 직경비(L/D 0.67, 1.67, 2.67), 내벽에서 좁아지는 각(57, $95^{\circ}$)이였다. 비기계적 에너지 투입량은 수분함량 20%, 사출구상수 2.23E-10 $m^3$에서 가장 높은 값을 나타내었다. 수분함량 20%에서 사출구상수가 증가하면, 직경팽화지수와 체적팽화지수는 증가하였다. 한편 수분함량 25%에서 직경팽화지수와 체적팽화지수는 사출구상수의 영향을 받지 않았다. 또한 길이팽화지수는 수분함량이 20%에서 25%로 증가할 때 증가하였으며 직경팽화지수와 음의 상관관계를 나타내었다. 수분흡착지수와 수분용해지수는 사출구상수에 영향을 받지 않았다.

• 산업식품공학
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• 제15권3호
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• pp.262-268
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• 2011

The effects of pellet moisture content on physical properties (expansion ratio, density and breaking strength) of vacuum-puffed Yukwa (non-oil puffed Yukwa) were investigated in this study. The Yukwa was made from the waxy rice steeped at 25 and $30^{\circ}C$ for 3, 5 and 10 days with pellet drying times (6, 8 and 10.5 hr). As the drying time increased from 6 to 10.5 hr at $50^{\circ}C$, the highest value of pellet moisture content (29.4%) was found in the samples made from the steeped waxy rice at $25^{\circ}C$ for 5 days after 6 hr drying, while the lowest value (16.3%) was found at $25^{\circ}C$ for 3 days after 10.5 hr drying. Both redness and yellowness values of vacuum-puffed Yukwa increased as the drying time increased. The expansion ratio of Yukwa was greatly affected by drying time, ranging from 2.07 (26.8% pellet moisture content) to 7.01 (24.0% pellet moisture content). From the data, it can be concluded that the pellet moisture content had a significant influence on the physical characteristics of vacuum-puffed Yukwa. With vacuum puffing condition of 3 min heating and 2 min puffing, the pellets with about 25% moisture content showed higher expansion ratio, and lower density and breaking strength.

• Preventive Nutrition and Food Science
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• 제17권3호
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• pp.203-209
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• 2012

The effects of variable moisture content, screw speed and barrel temperature on the physicochemical properties of red ginseng powder extrudates were investigated. The raw red ginseng powders were processed in a co-rotating intermeshing twin-screw extruder. Primary extrusion variables were feed moisture content (20 and 30%), screw speed (200 and 250 rpm) and barrel temperature (115 and $130^{\circ}C$). Extruded red ginseng showed higher crude saponin contents (6.72~7.18%) than raw red ginseng (5.50%). Tested extrusion conditions did not significantly affect the crude saponin content of extrudates. Increased feed moisture content resulted in increased bulk density, specific length, water absorption index (WAI), breaking strength, elastic modulus and crude protein content and decreased water solubility index (WSI) and expansion (p<0.05). Increased barrel temperature resulted in increased total sugar content, but decreased reducing sugar content in the extrudate (p<0.05). Furthermore, increased barrel temperature resulted in increased amino acid content and specific length and decreased expansion and bulk density of extrudates only at a higher feed moisture content. The physicochemical properties of extrudates were mainly dependent on the feed moisture content and barrel temperature, whereas the screw speed showed a lesser effect. These results will be used to help define optimized process conditions for controlling and predicting qualities and characteristics of extruded red ginseng.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.89-96
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• 1984

This study was intended to search the thermal properties of rice which are necessary in preventing qualitative and quantitative losses in the drying and milling processes. First, the coefficient of cubical thermal expansion of brown rice was measured, which is required for analyzing the internal stress of rice, and then theoretical thermal and moisture stresses were calculated. The results are summarized as follows: 1. The coefficient of cubical thermal expansion of brown rice was about $2.81{\times}10^{-4}/^{\circ}C$ in the temperature range of $10^{\circ}C-60^{\circ}C$. 2. When the shape of brown rice was assumed to be a sphere or a cylinder, maximum thermal stress due to temperature change of $20^{\circ}C-60^{\circ}C$ was in the range of $25-100kg/cm^2$. And maximum moisture stress was in the range of $450-650kg/cm^2$ when the drying temperature was $35^{\circ}C$, initial and final moisture contents of brown rice were 20% and 14% (w.b.), and the moisture diffusion coefficient was assumed to be $6.79{\times}10^{-4}cm^2/hr$. 3. Consequently, it was concluded that crack formation in a rice kernel is mainly caused by moisture stress.

• 한국식품과학회지
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• 제31권2호
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• pp.380-384
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• 1999

멸치를 이용한 팽화스낵제품을 개발하고자 부원료의 혼합비율, 팽화스낵 반데기의 적정수분함량, 튀김 조건 등 제조조건과 팽화제품의 단분자층 수분함량을 조사하였다. 멸치팽화스낵은 멸치육을 chopping하여 다시 colloid mill로 미분쇄한 다음 밀가루, 전분등 부원료와 식염과 양파를 혼합한 후에 압연하여 일정한 크기로 자른다음 건조, 기름튀김하여 제조하였다. 부원료의 배합은 멸치육에 밀가루를 동량으로 혼합한 경우 팽화율과 관능적 기호도가 가장 우수하였다. 반데기의 수분함량이 6.4%인 경우 제품의 팽화율이 최대치를 나타내었으며 $200^{\circ}C$의 대두유에서 14초간 튀김하였을 때 조직감이 가장 우수하였으며 제품의 단분자층 수분함량은 2.77%로 나타났다.

• 한국연초학회지
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• 제17권2호
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• pp.149-159
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• 1995

The freeze drying rate was investigated under various conditions such as pressure and moisture contents in order to establish the optimum condition for expansion of the culled flue cured tobacco lamina. The optimal pressure in the chamber to maintain the heat and mass transfer was about 0.8torr, When the moisture contents of sample was 50-60%, expanding rate was the optimum condition and the rate was 67-76%. As the thickness of the sample layers was increased, drying-rate was decreased conversely and this result seemed to be due to decline of heat and mass transfer coefficients. Differences with the position of its stalk were also observed in drying rate, and low stalk position leaves of 5 and 3 was the fastest. Key words : freeze drying, Popping, expansion tobacco.

• 한국연초학회지
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• 제19권1호
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• pp.70-75
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• 1997

The expansive properties of leaf tobacco by nitrogen gas was investigated with cut tobacco AB3O-1, CD3L-1(NC82). Major factors for the best expansion of the tobacco by the gas were an impregnated pressure and expansion temperature. The expansion rate for AB3O-1 and CD3L-1 at 250℃, 750kg/cm2 was 96.6%, 99.4% respectively. The shred size and fineness index at 96.6% of expansion rate for AB3O-1 was almost the same as at 58.3% for CD3L-1. The time reaching at equilibrium moisture under of RH 57% was 36hr in non-treated leaf tobacco, but it was 20hr in expanded tobacco. We confirmed that total sugar contents of leaf tobacco by the expansion was decreased with 9.3∼10.9%. Total alkaloid was decreased with 17.5∼21.1% and ether extracts was declined with 4.9∼9.3%. These results suggest that the expansion method of leaf tobacco by nitrogen gas is a useful method without any serious environmental troubles. Key words : expansion, nitrogen gas, heat treatment, tobacco.

• 한국인쇄학회지
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• 제16권2호
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• pp.23-36
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• 1998

Moisture content of printing paper and circumstance of printing room has great influence on the printing works. We have studied on the printability of domestic art paper according to the insufficient Korea weather. As the result, we found the printability of domestic art paper are much more affect by moisture content than any other printability coefficients, especially print density and hygroexpansivity decrease with moisture content increase.

• 한국식품영양과학회지
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• 제30권2호
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• pp.292-298
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• 2001

This study was conducted to investigate physicochemical properties of extrudates combining 4 levels of squid (0, 3, 5 and 7%) with 3 levels of defatted soy flour (0, 5, and 10%). Blends were adjusted to moisture content of 27% and then extruded in a single-screw laboratory extruder at 170rpm screw speed and 16$0^{\circ}C$ barrel temperature. The extruded materials were dried at 6$0^{\circ}C$ for 8hr to a moisture content of 3~4% and refrigerated at 4$^{\circ}C$ for 12 hour before examination for textural properties, expansion ratio, bulk density, shear force and Hunter color. Expansion ratio of extrudates decreased as squid content increased whereas bulk density and shear force increased. Expansion ratio of extrudates was not significantly different by defatted soyflour level. Bulk density of products decreased as defatted soyflour content increased but shear force of products increased as defatted soyflour content increased. In scores of sensory hedonic evaluation of snacks, appearance, flavor, texture and overall acceptability values had lowered as squid level increased. Therefore, according to materials contents on extrudates increased, nutritional contents of this products increased and also shear force and bulk density in physical properties increased whereas expansion ratio decreased.

• 감성과학
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• 제17권1호
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• pp.93-104
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• 2014

본 연구는 수분감응형섬유와 이들로 만들어진 니트의 흡습성, 건조특성 그리고 수분자발신장성과 같은 물성과 이들 니트소재의 여러 가지 염색시간과 온도에 따른 염색특성을 조사한다. 이를 위해서 HEF와 spandex를 심사로 사용하고 일반 PET와 aerocool 필라멘트를 커버링사로 사용한 3가지의 커버링사 시료를 준비하고 이들을 사용하여 3가지의 니트시료를 편직하고 이들을 염색온도와 시간을 달리하여 염색을 실시하였다. 3가지 니트시료의 흡습성, 건조특성 그리고 가역적 수축현상 등의 물성을 측정하고 실의 특성과 함께 분석하였으며 이들 니트시료의 용성을 FAST 시스템을 사용하여 측정하고 분석하였다. 그리고 이들 니트시료의 염착성, 색차 그리고 세탁견뢰도 등과 같은 염색특성을 측정하고 수분감응형 니트소재의 염색공정특성을 알아보기 위해 염색시간과 온도에 따른 이들 염착특성을 분석하였다.