• 제목/요약/키워드: peak viscosity

검색결과 462건 처리시간 0.028초

Sodium chloride와 sodium carbonate를 첨가한 yellow alkaline noodle sheet의 물리적 특성 (Physical Properties of Yellow Alkaline Noodle Sheet Added with Sodium Chloride and Sodium Carbonate)

  • 김순태;장학길;박영서
    • 한국식품과학회지
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    • 제39권1호
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    • pp.33-38
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    • 2007
  • 밀가루에 소금을 0, 2 및 4%를 첨가하였을 경우, Mixograph의 peak time은 밀가루의 종류에 관계없이 소금 첨가량이 증가함에 따라서 증가함을 알 수 있었으나 박력분의 경우에는 유의적인 차이를 나타내지는 않았다. Peak height와 width at peak도 소금 첨가량이 증가함에 따라 증가하는 경향을 나타내었으나 강력분과 중력분에서는 유의적인 차이를 나타내지 않았다. Width at 8 min의 경우에는 모든 밀가루에서 소금 첨가량이 증가함에 따라 증가하는 경향을 나타내었다. Sodium carbonate를 0, 0.5, 1.0 및 1.5의 농도로 밀가루에 첨가하여 Mixograph 특성을 관찰한 결과 밀가루의 종류에 관계없이 0.5% 첨가 시 peak time이 거의 2배정도 증가하였다가 그 보다 높은 농도에서는 다시 감소된 반면, peak height는 sodium carbonate 첨가량이 증가함에 따라서 감소하는 경향을 보였다. Mixograph peak time과 단백질 함량 및 침전가와는 유의적인 상관이 없었으나, peak height, width at peak 및 width at 8min과는 모두 정의 상관관계를 보여 주었다. 반죽의 초기호화온도, 최고점도, 최소점도, 최종점도는 밀가루의 종류에 관계없이 소금의 첨가량이 증가함에 따라 증가하는 경향을 나타내었으며, 최고점도, 최소점도 및 최종점도는 모든 밀가루에서 sodium carbonate 첨가량이 증가함에 따라서 유의적으로 증가하는 경향을 보였다. 초기호화온도와 보수율 및 알칼리수 흡수율과는 정의 상관이 있었으나, 보수율과 최고점도, 최소점도 및 최종점도와는 모두 부의 상관관계를 보여 주었다.

천연옥수수전분과 hydroxypropyl화 옥수수전분의 RVA특성과 필름 물성의 관계 (Relationship between RVA Properties and Film Physical Properties of Native Corn Starch and Hydroxypropylated Corn Starch)

  • 한윤정;김석신
    • 한국식품과학회지
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    • 제34권6호
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    • pp.1023-1029
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    • 2002
  • 본 연구는 천연전분과 hydroxypropyl화 전분에 가소제를 0, 16, 33, 50, 66% 비율로 첨가하여 RVA점도를 측정하고 필름을 제조한 후 물성을 측정하여 두 물성 사이의 상관관계를 알아보고자 행하였다. 필름의 인장강도는 가소제의 함량이 높아질수록 감소하였고 신장율과 수증기투과도는 증가하였으며 glycerol이 sorbitol보다 큰 변화를 보이는 것으로 나타났다. Hydroxypropyl화 전분이 천연전분에 비해 강도는 떨어지나 신장율은 높아지는 것으로 나타났고 수증기투과도는 2배 큰 것으로 나타났다. 가소제를 혼합하여 필름의 물성을 측정한 결과 sorbitol은 유연성보다는 필름의 강도를 유지하는 역할을 그리고 glycerol은 필름의 신장율을 증가시키는 역할을 하는 것으로 나타났다. RVA물성과 필름 물성의 관계에서 가장 연관성이 높은 것은 peak viscosity, 인장강도, 수증기투과도인 것으로 판명되었고 peak viscosity와 인장강도, peak viscosity와 수증기투과도의 관계는 각각 직선적인 것으로 나타났다. 따라서 RVA 물성 중 peak viscosity를 활용하여 필름의 인장강도, 수증기투과도를 예측할 수 있다고 판단되었다.

Glucomannan 의 유변학적 성질에 관한 연구 (A Study on the Rheological properties of Glucomannan)

  • 김경이
    • 유변학
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    • 제5권2호
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    • pp.161-169
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    • 1993
  • Glucomannan(G.M.)은 Amorphophallus Konjac C. Koch의 tuber로부터 분리되었고. 이 G.M.은 다시 침전제로 메탄올을 사용하여 4단계로 분별되었다.(F.1, F.2, F.3, F.4,). 각분 별물에 비하여 직선으로부터 벗어남을 보였다. Low shear viscometer로 G.M. 용액의 viscosity를 측정하였고 농도와 zero shear specific viscosity의 logarithm을 도시한 결과 inflection point를 나타내었다. 이것은 G.M. 분자들의 coil overlap의 시작에서 기인한 것이 고 묽은 용액에서 진한 용액으로의 전이행동은 임계농도. C*=4/[η]에서 일어났고 이때의 zero shear specific viscosity는 10을 나타내었다. 또한 specific viscosity는 묽은 용액에대해 서는 C14로써 변화하였고 진한 요액에서는 C3.0으로변화하였다. G.M.의 고체상태에 대한 유 전성($\varepsilon$',$\varepsilon$")과 점탄성(C',C")계수들을 액체질소 온도에서부터 15$0^{\circ}C$ 온도범위에 걸쳐 4단계로 film을 건조시키면서 10Hz에서 측정하였다. G.M. film의 유전성과 점탄성의 허수부 분은 ($\varepsilon$", C"), -10$0^{\circ}C$에서 peak를 나타내었고 이 peak는 hydroxy methyl 기들의 회전 운동에서 생겨난 것이다. 건조시키지 않은 상태의 G.M. film의 유전성과 점탄성의 허수부분 의 값들은 -5$0^{\circ}C$에서 물 분자의 운동에 의하여 생긴 peak를 보였다.

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Effects of harvesting times on pasting properties of starch in colored rices

  • Kim, Sang Kuk;Song, Young Un;Shin, Jong Hee;Kim, Se Jong
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.329-329
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    • 2017
  • The study was conducted to investigate the effects of different harvesting time on pasting properties of starch in three colored rices. Seven major parameters of starch pasting properties, peak viscosity (PKV), hot pasting viscosity (HPV), cool pasting viscosity (CPV), setback (CPV minus PKV), breakdown (PKV minus HPV), peak time, and pasting time were determined by Rapid Visco Analyzer. The peak viscosity, hot viscosity, cool viscosity and peak time were influenced by different harvesting times. Pasting time was delayed slightly with prolonged harvesting time in all rice cultivars. Pasting temperature in each rice cultivar differed from each harvesting time, and pasting temperature of the two rice cultivars, Hongjinju and Joseongheugchal, showed the highest at the 40 days after heading and then it decreased at the final harvesting time. With the delay of the harvesting time, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature did not exhibit a regular trend depending on their genetic characteristics. Branch chain length distribution of amylopectin was demonstrated a distinct difference among these colored rices. In changes of amylopectin branch chain-length distribution, the amylopectin structure of Hongjinju rice cultivar as affected by different harvesting time, the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant increase in A chains with $DP{\geq}12$ and remarked decrease in long chains $37{\leq}DP$ compared to that of 30, 40, and 50 days after heading. In particular, when harvesting time is delayed the distribution percentage of short chain (A chains with $DP{\geq}12$) was increased except for the rice which harvested 20 days after heading. The similar results were also observed in Sintoheugmi rice cultivar like that of Hongjinju rice cultivar. Otherwise, distribution percentage of the shortest chain length of amylopectin in rice starch harvested at 20 days after heading was characterized by the significant decrease in A chains with $DP{\geq}12$ and remarked increase in B chains $13{\leq}DP{\geq}24$ compared to that of 30, 40, and 50 days after heading.

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Effects of Extrusion Conditions on Pasting Properties of Potato

  • Cha, Jae-Yoon;Ng, Perry K.W.;Shin, Han-Seung;Cash, Jerry
    • Food Science and Biotechnology
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    • 제16권5호
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    • pp.783-788
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    • 2007
  • An advantage to the extrusion of raw potatoes is a reduction in the energy input required to process potato products; however, the effects of extrusion on the properties of raw potato have not been studied. The purposes of this study were to develop a workable extrusion process for raw potato and to study the effects of extrusion conditions on the pasting properties of extruded potato products. The peak viscosity, final viscosity, pasting temperature, water solubility index, and water absorption index of pressed and pressed-dried potato extrudates decreased as die exit temperature increased, whereas they did not change as screw speed increased. The peak viscosity, final viscosity, and water solubility of steam-cooked potato products decreased with extrusion processing; however, they did not change with increasing die exit temperature and screw speed. Potato products with different degrees of depolymerization of extruded potato starch, depending on die exit temperature, were produced from raw potatoes.

유색미가루와 현미가루를 첨가한 국수제조 및 품질특성 (Quality Characteristics and Preparation of Noodles from Brown Rice Flour and Colored Rice Flour)

  • 이원종;정진구
    • 한국조리학회지
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    • 제8권3호
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    • pp.267-278
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    • 2002
  • 단백질 함유량은 유색미가루가 밀가루보다 적지만 현미가루보다는 함유량이 많았고, 지방함량과 회분함량에서는 현미와 비슷하였다. 현미가루는 유색미가루보다 peak viscosity, holding viscosity, breakdown viscosity, final viscosity에서 높았을 뿐만 아니라 setback viscosity에서도 높았지만 유색미가루는 호화점도에서 현미가루 뿐만 아니라 밀가루보다도 월등히 낮았다. 현미가루와 흑미가루는 5.3~6.4%의 총 식이섬유를 함유하였으나 수용성 식이섬유의 함량은 낮은 반면 주로 불용성 식이섬유를 함유하였다. 건조면과 조리면의 cutting force는 현미가루와 유색미가루의 혼합비율을 높이면 감소하였고 조리면의 경우에는 찰흑미가루 10%와 화성현미가루 20%를 첨가했을 때 밀가루 100%로 만든 대조군과 큰 차이가 없었다. 국수의 기능성을 높이고 기호도를 향상시키기 위하여 현미가루와 유색미가루를 10~30%를 첨가하여 관능검사를 실험한 결과 현미가루 20%와 찰흑미가루 20%를 첨가한 국수가 가장 높은 관능적 평가를 받았다.

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홍고추액을 첨가한 생면 파스타의 품질특성 (Quality Characteristics of Fresh Pasta Noodle Added with Red Hot Pepper Juice)

  • 김정수;홍진숙
    • 한국식품조리과학회지
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    • 제24권6호
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    • pp.882-890
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    • 2008
  • The present study investigated the influence of different volumes of red hot pepper juice on the quality characteristics of fresh Pasta noodle. Supplementation with 0% (control), 2.5%, 5%, 7.5%, or 10% red hot pepper juice produced similar gelatinization characteristics of peak viscosity, temperature at peak viscosity, hot paste viscosity and numerical value of breakdown. However, increasing concentrations of red hot pepper juice produced progressively and significantly low cold paste viscosity and setback. The chromaticity of wet and cooked noodles was significantly lower in L value and significantly higher in +a and +b values with increasing volumes of red hot pepper juice. The texture of fresh noodles displayed no significant differences in hardness, adhesiveness and chewiness. The springiness and cohesiveness were lower and higher with the increase of added red hot pepper juice, respectively, but the differences just attained significance. For cooked noodles, adhesiveness, springiness, cohesiveness and chewiness tended to be higher with increasing volumes of red hot pepper juice, but again the differences just attained significance. Cooking characteristics of weight, volume, moisture absorptive power and turbidity decreased with increasing volumes of red hot pepper juice. Sensory characteristics of acceptability including appearance, color, flavor, taste, texture and overall-acceptability improved with increasing red hot pepper juice volume, in particular with 5% and 7.5%. Amylograph characteristics for initial paste temperature positively correlated with the texture characteristics for chewiness (p<0.05). Negatively correlated amylograph parameters included texture for springiness with for peak viscosity (p<0.01), texture for adhesiveness with hot paste viscosity (p<0.01) and breakdown with texture for adhesiveness, cohesiveness and chewiness (p<0.05).

Patient-Specific Computational Fluid Dynamics in Ruptured Posterior Communicating Aneurysms Using Measured Non-Newtonian Viscosity : A Preliminary Study

  • Lee, Ui Yun;Jung, Jinmu;Kwak, Hyo Sung;Lee, Dong Hwan;Chung, Gyung Ho;Park, Jung Soo;Koh, Eun Jeong
    • Journal of Korean Neurosurgical Society
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    • 제62권2호
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    • pp.183-192
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    • 2019
  • Objective : The objective of this study was to analyze patient-specific blood flow in ruptured aneurysms using obtained non-Newtonian viscosity and to observe associated hemodynamic features and morphological effects. Methods : Five patients with acute subarachnoid hemorrhage caused by ruptured posterior communicating artery aneurysms were included in the study. Patients' blood samples were measured immediately after enrollment. Computational fluid dynamics (CFD) was conducted to evaluate viscosity distributions and wall shear stress (WSS) distributions using a patient-specific geometric model and shear-thinning viscosity properties. Results : Substantial viscosity change was found at the dome of the aneurysms studied when applying non-Newtonian blood viscosity measured at peak-systole and end-diastole. The maximal WSS of the non-Newtonian model on an aneurysm at peak-systole was approximately 16% lower compared to Newtonian fluid, and most of the hemodynamic features of Newtonian flow at the aneurysms were higher, except for minimal WSS value. However, the differences between the Newtonian and non-Newtonian flow were not statistically significant. Rupture point of an aneurysm showed low WSS regardless of Newtonian or non-Newtonian CFD analyses. Conclusion : By using measured non-Newtonian viscosity and geometry on patient-specific CFD analysis, morphologic differences in hemodynamic features, such as changes in whole blood viscosity and WSS, were observed. Therefore, measured non-Newtonian viscosity might be possibly useful to obtain patient-specific hemodynamic and morphologic result.

자색 고구마 분말 첨가 생면의 품질 특성 (Quality Characteristics of Wet Noodles Added with Purple Sweet Potato Powder)

  • 이재상;유승석
    • 동아시아식생활학회지
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    • 제22권4호
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    • pp.489-496
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    • 2012
  • This research investigated the quality characteristics and anthocyanin content of wet noodles according to the amount of freeze-dried purple sweet potato powder. For viscosity, initial pasting temperature tended to increase compared to the control group, whereas peak viscosity, peak viscosity time and final viscosity steadily decreased. As the amount of purple sweet potato powder increased, breakdown value of viscosity and set back value significantly decreased. For chromaticity, as the amount of purple sweet potato powder increased, L-value decreased gradually, whereas a-value gradually increased and b-value significantly decreased compared to the control group. Anthocyanin content significantly increased in the addidtive group (91.79) compared to the control group (70.20). Measurement of texture characteristics found that hardness was highest in the control group, but it decreased as the amount of purple sweet potato powder increased. Springiness, gumminess and chewiness were highest in the control group. In the sensory evaluation, color, odor, chewiness, and overall acceptance were high in the 6% addictive group. In this study, by investigating the anthocyanin contents, quality characteristics and sensory attributes of wet noodles with freeze-dried purple sweet potato powder, we found that the 6% additive group is the best. Our results provide basic information for the development of noodles with purple sweet potato powder.

우리나라 생면용 밀가루의 성질 (Physicochemical Properties of Korean Raw Noodle Flours)

  • 신숭녕;김성곤
    • 한국식품과학회지
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    • 제37권3호
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    • pp.418-424
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    • 2005
  • 호주 표준 흰 밀(ASW) 단독 또는 ASW와 호주경질밀 또는 미국 밀(서부 횐 밀, 경질 붉은 겨울 밀)을 혼합 제분한 생면용 밀가루의 일반 성분과 색도, 입도분포, 호화성질, 리올로지 성질을 비교하였다. 단백질과 회분 함량은 ASW 밀가루가 평균 8.51%와 0.375%(수분 14% 기준)로서 혼합밀가루의 9.20%와 0.406%보다 낮았다. 밀가루의 색도는 명도와 황색도는 ASW 밀가루와 혼합밀가루 사이에 차이가 없었다. 밀가루의 평균 입자 크기는 ASW 밀가루가 작았으나 표면적은 두 집단별 차이가 없었다. 밀가루 팽윤부피는 ASW 밀가루가 높은 경향이였으나 유의적인 차이는 아니었다. 신속점도계에 의한 최고점도는 ASW 밀가루가 높았다. 파리노그래프와 익스텐시그래프 특성값은 두 집단 사이에 유의적인 차이가 없었다. 단백질 함량은 밀가루의 평균입자크기, 파리노그래프의 반죽안정성, 익스텐시그래프의 신장도와 (+)상관을, 팽윤부피, RVA 최고점도와는 (-)상관을 보였다. 밀가루 팽윤부피는 RVA 최고점도와 (+)상관을 보였다. 팽윤부피와 최고점도는 파리노그래프 또는 익스텐시그래프 특성 값과는 상관을 보이지 않았다.